SIGHT, The Story of Vision2

In a Newsweek Magazine feature article, January 11, 1999, The Power of Big Ideas” it began, “Scientists nominate the most important inventions of the past 2000 years……….What changed the course of human events most profoundly?”The top inventions included the clock, numbers, the Gutenberg Press, the computer, and several others everyone could easily appreciate. The first paragraph describes simple reading glasses because “they have effectively doubled the active life of everyone who reads or does fine work – and prevented the world from being ruled by people under 40”. Glasses also “foster the mind-set that people need not accept the body nature gave them, and that physical limitations can be overcome with ingenuity”. When we look back, we can certainly say that optical glass has had a profound impact on mankind. Eyeglasses might be considered the greatest example of functional art as well as assistive technology. And, as Professor Spencer Di Scala (teacher, scholar, innovator, public intellectual, UMass Boston Professor of History) said, “The art of making a pair of spectacles was an achievement of monumental significance for mankind that has had an incalculable impact. Although it has been relatively unknown to the general public, the evolution and development of spectacles over the past seven centuries qualifies as a long, significant, and quite fascinating journey through history, whose impact deserves to be better recognized and more widely appreciated.” 151

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CHAPTER 9 Contact LensesCONTACT LENSESGary Orsborn, VP, Global Professional and Clinical Affairs, CooperVision. “When contact lenses were first made commercially available over 40 years ago no one could imagine that so many different types of contact lenses would be available today. When they were first introduced they were only for people with myopia. But today, whether you're farsighted, nearsighted, with astigmatism, if you have presbyopia... regardless of your vision impairment, regardless of your refractive error, your prescription can be made into contact lenses.” If you have astigmatism, “...Toric contact lenses are designed for the correction of astigmatism and have special stabilization features within the design to allow the lens to orient and remain stable on the eye, regardless of how your head turns or where you are looking. It allows for clear, stable vision through the correction of astigmatism. Contact lenses can be used to correct presbyopia. With presbyopia, the crystalline lens inside the eye becomes less 153

flexible and we lose to ability to accommodate. Accommodation is when the lens becomes more convex in shape to increase power so we can see up close. As we age, around age 45, we lose that ability to accommodate. There are a variety of ways contact lenses are used. One way is called mono-vision. With mono-vision one eye usually the dominant eye, that is the eye that you would sight with if you were to use a camera, would be corrected for distance vision. The other eye, the non-dominant eye would be corrected for near vision. Any type of contact lenses can be used for mono-vision. As the prescription increases for reading (as you age), some patients lose some binocular vision and stereopsis declines. There are also special design lenses for presbyopia. Bifocal contact lenses or more appropriately called multifocal contact lenses correct both eyes together. They are called ‘Multifocal’ because you can see clearly at all distances, far away, at near, and intermediate distances also. And, that intermediate distance vision is very important for many who work in an office environment, with a desktop computer screen and the work on the desk. People who use different devices for reading, for social networking, intermediate vision can be very important. Multifocal contact lenses are very useful for correcting presbyopia and are one of the reasons contact lenses today are becoming more popular around the world.”CONTACT LENSES DON’T CHANGE YOUR APPEARANCE... VISION IS CLEAR, BRIGHT, WITH A NATURAL FIELD OF VIEW. 154

00:00 / 00:00 “Whether you're farsighted, nearsighted, with astigmatism, if you have presbyopia... Regardless of your vision impairment, regardless of your refractive error, your prescription can be made into contact lenses”,Gary Orsborn, OD, VP, Global and Professional Affairs, CooperVision.“There are so many reasons to choose contact lenses. First and foremost it gives a natural field of vision because they’re shaped and flexible to conform to your eye. There is no obstruction, you see the world clearly. The world is brighter, and you don't have any interference. This is especially important when you need that full field of vision like in sports or in driving. There are many advantages wearing contact lenses everyday. If you are living somewhere where there's precipitation and rain or snow or going in and out of the cold, there is no interference with contact lenses. A big advantage is people can see you just for who you are.They can look into your eyes without any kind of barrier. They see your beautiful eyes, and we know how important that is. People going to proms or in their wedding photos or on their wedding day, want to see clearly but not wear glasses. 155

They can choose contact lenses. I got my first glasses when I was in second grade. The first kiss I received from a girl was when I was in third grade and I thought I had to take off my glasses for that. When wearing contact lenses you can be as close as you want to people without any obstruction. Be seen for who you really are.It’s important to follow your eye care professional’s advice on when to replace lenses, how to wear them, how long to wear them every day, and how to care of them. If you are wearing reusable lenses and they are taken out of your eyes, proper lens care solutions must be used used and the instructions for storage must be followed.” 156

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CONTACT LENSES AND THE ATHLETEAdapted from Specialty Contact Lenses, Linda Conlin, ABOC, NCLEC, 20/20 Magazine, Apr 2016The visual demands of athletes are greater than those of non-athletes, going beyond correction to 20/20. The visual skills required for sports and a competitive edge are reaction time, focus/acuity, peripheral vision, depth perception, fixation/fusion/tracking, contrast sensitivity and eye-hand coordination.The more quickly and clearly the athlete can see the stimulus, the faster the reaction. Contact lenses have the advantage over spectacles because they offer more accurate image size, as well as fewer aberrations, less glare and no reflections. They also won’t slip down, fall off, fog up or become covered with dust, mud or sweat. The peripheral vision field increases by 15% with contact lenses versus spectacles, a big benefit in most dynamic sports. Depth perception improves in anisometropia (a prescription difference in each eye of more than a diopter) because contact lenses will bring the image sizes in both eyes closer in-line, helping the athlete with spatial self-awareness. Because the contact lens moves with the eye keeping the optimal vision correction directly over the pupil, it is easier to track a moving target. According to researchers at University College, London, and Cambridge University, athletes depend on their visual cues combined with 158

body motion for spatial self-awareness. It's a critical need for gymnasts, divers, and even a basketball player’s long glide to a dunk.Outdoor sports result in long periods of exposure to sunlight. Often, sunglasses are impractical for the same reasons as spectacles. Without protection, rhodopsin, the primary pigment in the rod photoreceptors of the retina, bleaches. This results in a loss of acuity and contrast sensitivity plus the sensitivity of the rods for peripheral motion detection. UV attenuating contact lenses, especially with a tint, can provide some protection. Lenses that block blue light can enhance clarity and contrast. Blue light tends to focus in front of the retina, resulting in glare or blur. Blocking blue light focuses the remaining light in a tighter range, improving acuity and contrast sensitivity.Tints in contact lenses also can be sport specific. For example, amber lenses enhance detail, and objects appear to “pop” off the background. They help athletes in fast moving sports such as baseball, field hockey, lacrosse, softball, soccer and tennis. Some professional baseball players have tried red contact lenses for the same result. Grey/green lenses enhance red and green to improve detail and contour recognition.v Consider recommending them to patients who participate in sports such as football, golf, rugby, running and cross-training. My son used grey/green lenses for competitive rowing after his third pair of sunglasses went overboard, and found the reduction of glare and better peripheral vision beneficial.”CHILDREN AND CONTACTSBy age 2, children’s eyes are the same size as adults’, allowing the use standard size contact lenses. Children tend to be healthier than adults, and so have fewer systemic considerations for contact lens wear. Younger children tend to “follow the rules” and have closer adult supervision. According to a 2007 study of 84 children ages 8 to 12 and 85 children ages 13 to 17 newly fit 159

with contact lenses, the younger group required only 15 minutes more chair time over three months.Also, children have increased participation in athletics, increased interest in contact lenses at a younger age and there is increased in children’s confidence with contact lenses over spectacles.A BIT OF CONTACT LENS HISTORY“Though contact lenses seem to be a recent phenomenon, the famous Italian architect, mathematician and inventor Leonardo da Vinci (1452-1519) produced the first known sketches (in 1508) that suggested the optics of the human eye could be altered by placing the cornea directly in contact with water.But it's true that when contact lenses were invented for real came much later. Many believe da Vinci's ideas eventually led to the development of contact lenses more than 350 years afterward.” For more about the history of contact lenses visit All About Vision. 160

CARING FOR CONTACT LENSESFrom Dr. Orsborn, “It's very important for anyone who is wearing contact lenses to have a healthy wear and care regimen that has been recommended by a eye care professional.Regardless of the type of contact lens that is being worn, soft contact lens, gas permeable contact lens or a hybrid type, there are proper ways of wearing them and for caring for them. The simplest and certainly becoming increasingly the most popular type are one day contact lenses. These are the lensesthat are single use, you put them on in the morning and take them out at night before you go to sleep. They are taken out and thrown away. It's that simple.One of the most important steps in caring for contact lenses is the proper hygiene of washing hands. Use a non-fragrance, non-oily type of soap and dry the hands with a lint free towel. If reusable lenses are stored overnight in a lens case, take them out of the case with clean hands (because the fingers can be a vector for introducing micro-organisms into the eye that can cause infections) and insert them as taught by the professionals in your doctor’s office.Infections are extremely rare but they can happen. They can essentially be avoided with clean hands and a proper care regimen.” Gary Orsborn, VP, Global Professional and Clinical Affairs, Cooper Vision.DRUG RELEASING CONTACT LENSES 161

Joseph B. Ciolino, MD, Assistant Professor of Ophthalmology, Massachusetts Eye and Ear Infirmary, whose, “...primary research project is working to develop a drug releasing contact lens. And, one of the inspirations for the project were our choroidal prosthesis patients that require a contact lens and antibiotics and without either of them, can have devastating complications. So initially they, the patients were, I guess you could say some of the inspiration behind the desire of developing a drug releasing contact lens.”How does it work? “The contact lens itself, has inside of it a very thin drug polymer film which is a ring throughout the periphery. Now that thin drug polymer film helps us slow the release of a drug out of the contact lens. The period of time that we want to release the medication really depends on the ophthalmic indication. So for instance, for the treatment of glaucoma we're really looking at compliance. And even though the medications are effective, often times the, our patients may not be compliant with taking them. Therefore, the idea is we would decrease the burden of treatment, by having extended release contact lenses. So, we're working on developing a lens that could potentially release a medication for as long as one month. And, so far over our animal studies we've shown that indeed that certainly is possible.For glaucoma, for example, the medications are effective. However, compliance remains a concern meaning that sometimes patients don't take the medications as their supposed 162

to. And to make things a little more complicated is that sometimes they take the medication right before they come and see us. Like someone who would brush their teeth before going to see the dentist, they'll take the drops right before they see us so that the drops may look like they’re being effective, meaning that the pressure in the eye goes down. However, there may be evidence of progression of the disease. So it can make it difficult to differentiate the effectiveness of the medication from actual compliance. One of the benefits from a drug releasing contact lens is that it provides sustained release for about a month. Therefore, we can imagine a world where a patient would put in a contact lens and it would deliver the medication for one month. The drug releasing contact lens really has a wide array of potential applications. It's really a platform. And so, another area beyond glaucoma, where I think it could be effective, is for the treatment of intraocular inflammation. For instance, there is a condition called Iritis or Uveitis particularly on the front of the eye where patients have to use steroid eye drops every hour, sometimes throughout the night. You can imagine that it is difficult to take the drop every hour. You can see the advantage of the application of a contact lens, where a patient, instead of receiving a drop every hour, can have the ophthalmologist place a contact lens on the eye and one week later take it out. I could really see the drug releasing contact lens being used for intraocular inflammation, as well as other conditions such as corneal rejection, other areas of inflammation including post operative inflammation.”THERAPEUTIC CONTACT LENSESFrom Dr. Ciolino, “The question is asked as to whether or not it's safe to wear a contact lens overnight particularly for continuous wear. I think in the situation of a therapeutic contact lens that's treating a condition the risk benefit ratio changes as opposed to 163

just wearing a contact lens for convenience or cosmetic reasons. Surprisingly we actually bandage contact lenses for therapeutic reasons quite often in patients who really are the worst candidates for contact lenses such as, maybe some people who are older in age and also have dry eyes and diseases of the surface of their eye including scratches that won't heal. And, surprisingly, these lenses are worn continuously are tolerated quite well. So I think that historically if we look at this patient population we can see that there is the opportunity to wearing contact lenses continuously as a therapeutic modality.”RESOURCES CooperVision, About Contact Lenses All About Vision, Consumer Guide to Contact Lenses 164

Image: Ilene Mattison-Shupnick CHAPTER 10Coolest Optical System In An Animal On The PlanetWhen Dr. Schwab is asked the question, “What is the coolest optical system on earth?” He says, “I'm going to give a few examples of cool systems to me seem better then anything you could make up. You can't, you can't think some of this stuff up. For example, and this is one I'm particularly fond of. Certain birds will eat raptors. Certain birds will hunt mice. Okay, so if they hunt a mouse and their flying low over a marsh and a mouse is aware of that bird, the mouse will run from it and try to hide. Well, in the 165

flight or fight response when any of us run and we have a frightening experience we tend to have the urge to urinate, to empty our bladders. So does the mouse. The mouse will pee often to lighten its load to disappear to another clump of grass. Turns out that urine will give off the color of ultraviolet so that the bird that is looking down on it, may follow this track of urine by virtue of ultraviolet given off by the urine. Essentially, the urine is pointing directly towards the mouse. It's given itself away to the visual system of the predator. I see that as a very cool system. It's aligned itself with its prey. When I see a bird like a Peregrine falcon attack I know more about how it attacks because of studies that have been done. But the bird doesn't attack straight on to its target. It tends to spiral around it and as it spirals around it it will use one eye to focus on that target. But as it gets closer it's gonna needs stereoscopic vision and that's when it turns and has a single line attack. And when it does it has stereoscopic vision with a second fovea. Now, it's important to give you a little description. You have two fovea, one in each eye. A fovea is the sharpest point of vision in the eye. Most raptors like the Peregrine will have two in each eye. They can't use that second fovea for stereoscopic vision until it gets closer to it's prey. But the surprise here is that the image swings out to that second fovea and the stereoscopic vision comes in to play for the falcon. As the falcon now approaches its prey at great speed it has to have stereoscopic vision because it's prey may move in any three dimensional direction. The falcon will then be able to strike with this stereoscopic vision and usually have a high degree of success. The highest degree of success as a predator though and this might be even better than the falcon in some ways is the dragonfly, the humble dragonfly that you see in your backyard. The reason why I say this is that the dragonfly is about 95% successful when attacking it's prey. It has approximately, at least 166

the bigger ones, have approximately 30,000 units in each compound eye to create both stereoscopic vision, putting those two together as well as a big field of view using ocular or one eye vision. It attacks from behind and from below and once it picks out a target, that target is toast. It manages to overtake the target with both speed, surprise, and excellent vision for an insect. It is descended from a related animal that was here during the Carboniferous period, a giant dragonfly. They are not directed related but they are cousins. This giant dragonfly called a Griffenfly was larger than a crow and it's eyeballs were larger then golf balls. Imagine that at your picnic. Meganoptera, Source: wikepedia 167

You've seen Kingfisher in the field but have you ever thought about the way they hunt? A Kingfisher will sight a fish in shallow water and will hover over that animal, and by hovering will be able to fix the fish in his vision. High-speed film can show you that the head of the Kingfisher does not move as it hovers. It's really phenomenal because of the vision the head stays locked still and yet the body will move and the wings will move. When the Kingfisher is certain that the fish is it the right position it will fold it's wings back and drop like a stone on top of the fish. Now it has a problem. As it strikes the water the bill is going to send out a shockwave, and that shockwave is going to strike the lateral line on the fish. They have their own defense mechanisms. So the fish is going to sense this shockwave and is going to be able to move as a result in a three dimensional world. Now if you think about it, if we're hunting say a deer even though it's a three-dimensional world it isn't really. It's really two-dimensional cause the deer can't fly. So we are more in a two dimensional world. I do realize it's three-dimensional. I'm only saying that as compared to a fish or an animal that flies their much more in a three dimensional world. So as the Kingfisher drops and strikes the water a shockwave is sent out as the Kingfisher drops the shockwave is sent out and the fish now can move in any direction. So what does the Kingfisher do? Kingfisher solves this problem by once it gets his head underwater it has a fovea that area of sharpest vision in the eye, out near the periphery of the retina. Furthermore, the lens is asymmetric, meaning that light rays that come in the eye are bent in such a way as to strike that second fovea. In stereo, this is quite a feat because the cornea, the front of the eye, is about the same index of refraction as the water. So that means that the cornea is no longer useful to help bend the rays to get the image to the fovea. It has to be done all by the lens, and it is. Once that image then is portrayed in the two fovea in each eye, in the periphery of the eye, the Kingfisher can now essentially see 168

underwater to attack a fish that's moving in whatever direction it wants and still be able to come up with that fish most of the time. The surprise here is that the Kingfisher makes its living this way and yet if you think about it the challenges it has to face are finding the fish, being able to penetrate the water, then being able to drop on the fish without frightening it, then being able to see it underwater, follow it, and catch it. Quite a feat. So the next time you watch a Kingfisher attack a fish think what's going on and the process in its brain from the eyes to the brain, to the system of tracking, even a cerebellum, the part that help keep balance and keeps the wings flying. Do birds get presbyopic? Good question...Probably not, because any animal in the wild that doesn't see exactly perfectly probably doesn't make it. So, they probably don't get presbyopia. Besides their lenses are much softer than ours. I want to tell you about one more animal that is particularly intriguing to me, it'll be in your backyard this Spring and Summer. Some people may even choose to step on it. They may not really see and realize what's going on and it has a spectacular visual system and that's the jumping spider. Jumping spiders are often small, often no bigger then a single digit on your finger and they are charming, positively charming. If you get up close to them and you look at them, they'll look back at you, even engage you with a bit of personality. And when you move from side to side they can't follow you with their eyes because the external portion of their eyes are fixed in their carapace. So they'll jump to follow you as you move back and forth. But those fixed lenses on the surface of the carapace bely a beautiful system beneath it. Remember, these are small animals so they have to have good visual acuity within those eyes, or otherwise they wouldn't capture their prey. How do they do it? First of all that single lens is all they've got for a lens. Yet they have a Galilean telescope because they have a second element. 169

The front lens is attached to a tube like structure at the back of the tube they have retinal cells called retinal cells but it doesn't matter about the name, their very similar analogous if you will to the retinal cells we have. Those cells are arranged in such a way as to form a \"V\". Now, without getting into optics too much, the light rays that come in are already focused by the first lens will strike the retina and will bend outwards, a magnifying lens if you will. Then it becomes a two lensed element of an eye. The lens at the front, which everybody would call it a lens, but the second portion of the anatomy, this \"V\" like shape of the fovea if you want to call it a fovea, permits the magnification at that level. If they see another spider they want to eat, or an insect how do they paint that picture? In essence, it is a raster scan, much like the scan on your TV or your computer. They scan back and forth rapidly. They'll go line by line, by line, and the brain which is not much bigger then a pinhead will put all that together instantly, very much like your TV screen. Now they have an image, but how do they see color? Because surely, with those few photoreceptors they can't see the range of color. They can, and they do. They have more color receptors than you do. They have four. You have three. At least most of them have four. So how do they arrange them? I mean you can't possibly have all those cells arranged in a flat array like ours. They don't. They have them stacked. The light rays that enter this stack of photoreceptors. Perhaps if it is a blue wavelength, it's absorbed to begin with, as it's a medium wavelength, it's absorbed at the second level and eventually the third level and so on until all the photons, all the portions of the light ray are absorbed. Now, if this system were applied to photography, you could overnight double, triple, quadruple the power of a card because you would stack the color receptors rather then putting them in a flat array. It's a magnificent system. It’s very well designed and at short range, these creatures see 170

just about as well as you do. They don't see at great distance, but they do see close up very well. Furthermore, that tiny brain, in the best of the jumping spiders, can and does set ambushes. In other words they can go behind a leaf to wait on their prey to come out on the other side. That takes planning. That takes conceptual understanding of what's gonna happen. All that in that little brain. It's magnificent and yet you may see this on your plants and want to squash them, don't do it. They are harmless, they have personality and they have a visual system that is awe-inspiring.”Ivan Schwab MD, Professor of Ophthalmology, UC Davis 171

CHAPTER 11Common Eye DiseasesCONJUNCTIVITIS Images, courtesy of AllAboutVision.comPINK EYE? Known someone that has it? If so, you know that it is very contagious and requires a visit to the eye doctor. In fact, it's likely that it affects both eyes. 172

“Conjunctivitis is an inflammation of the conjunctiva that lines the inside of the lid and the top layer over the eye. Because of the dried sticky yellow discharge, people often wake up in the morning with eyes ‘glued’ shut. Vision is blurred and the eyes will itch. Conjunctivitis affects not only the whites of the eyes, making the blood vessels inflamed and therefore more visible, it also affects the inner lining of the eyelids. Doctors will examine patients under the slit lamp biomicroscope to look not only at the bulbar conjunctiva or the whites of the eyes but also at the palpebral conjunctiva or the inner linings of the eyelids to help determine the type of conjunctivitis or the cause of the redness. Not everyone with a red eye has pink eye so it is important for an eye care professional to examine a patient to determine the reason why the eye is red and then treat it appropriately. Other causes of red eyes could be allergies, dry eye syndrome, chemical burn or injury to the eye, subconjunctival hemorrhage or broken blood vessel on the whites of the eyes, corneal ulcer, herpes, the cold/flu virus. These conditions are all treated very differently so its best to be examined by a doctor instead of self-medicating or just waiting and hoping the red eye will go away on its own.” Cheryl Murphy ODFrom AllAboutVision.com, All forms of conjunctivitis — including bacterial, viral, allergic and other types — involve inflammation of the transparent, mucous membrane (conjunctiva) covering the white part of the eye or sclera. Infectious causes of an inflamed eye and conjunctivitis include bacteria, viruses and fungi. Non-infectious causes include allergies, foreign bodies and chemicals.The phrase \"pink eye\" is commonly used to refer to conjunctivitis, because pinkness or redness of the conjunctiva is one of the most noticeable symptoms.There are different types of conjunctivitis but the main one the general public is most familiar with is probably pink eye or viral conjunctivitis. These patients typically present with one red eye 173

but since viral conjunctivitis is contagious, sometimes patients walk in with two red eyes having inadvertently given it to themselves in the other eye. Visit AllAboutVision.com for a more complete discussion about conjunctivitis. CHALAZION Image, courtesy of AllAboutVision.comA CHALAZION is an inflammation of the meibomian gland, inside the lid, due to a blocked duct. It’s a cyst. Unlike a stye, it usually points inside the lid. While it can go away over time, large chalazia may require treatment by an eye doctor.From AllAboutVision.com, “A chalazion is a benign, painless bump or nodule inside the upper or lower eyelid. Chalazia (plural for chalazion) result from healed internal styes that no longer are infectious. These cyst-like nodules form around an oil gland (meibomian) within the eyelid, resulting in red, swollen eyelids.The contents of a chalazion include pus and blocked fatty secretions (lipids) that normally help lubricate the eye but can no longer drain out. Normally chalazia will drain on their own, but a persistent chalazion requires treatment by an eye doctor.Many chalazia drain, resolving on their own, especially if you facilitate the process with periodic warm compresses and gentle massage of the eyelid. However, some chalazia persist for more than several weeks and grow large enough to become cosmetically unappealing. A larger chalazion may press on the 174

cornea, temporarily creating irregularity on the eye surface and inducing astigmatism. This can cause blurry vision. (Courtesy, AllAboutVision.com, Brian Chou OD, Marilyn Haddrill) STYE/HORDEOLUM Image, courtesy of AllAboutVision.comA stye or hordeolum is an infection of an oil gland at the edge of the lid. It’s usually from staph bacteria and looks like a pimple and usually points outside the lid. It will eventually break, drain and heal. The best way to prevent them for patients that are prone to styes is to practice better eyelid hygiene, washing or shampooing frequently.Visit AllAboutVision.com to learn the, “7 Eye Stye Facts: Symptoms, Causes and Treatment”, by Liz Segre; reviewed by Vance Thompson, MDSTRABISMUS 175

Image, courtesy of AllAboutVision.com“STRABISMUS is a condition in which the two eyes do not both accurately aim at the same object. One eye may be turned too far in or too far out. This could be due to the extra-ocular muscles of the eye not coordinating their eye movements and aiming the way they should. When each eye is not aimed at the same point in space at the same time, two different images are sent to the brain, one from each eye, and this can be visually confusing for the brain. The brain may learn to ignore the image from the eye that is not aimed where it should. This can lead to suppression of information from that eye. If information is not received by the brain from that eye while a person is young and their brain is still wiring itself, then it may not make the appropriate amount of neural connections it needs to have good clarity of vision in that eye. This would then result in the person suffering from double vision, decreased depth perception or 3D vision or decreased 176

best potential vision in that eye. If a child is hyperopic, to correct vision we would provide a plus lens. However, children subconsciously learn that if they accommodate, they can make their eye more plus and make things clear. Unfortunately, accommodation and convergence are linked. Therefore, when we accommodate our eyes converge; turn in and, vice versa. If a child does this for distance vision, it results in double vision and that will be a problem. The treatment is to provide bifocals or progressives so that the child does not have to accommodate and the eyes can be trained to not converge for clear vision.It is important to catch and treat strabismus early on in life, while visual development and wiring is still actively happening between the eyes and the brain. Experts say that learning is 80% visual so we do not want a young patient to have difficulty reading or learning in school due to vision or eye related issues. Strabismus is usually treated first by prescribing glasses, if needed, then by patching the good eye or fogging the good eye with eyedrops so that the eye muscles of the strabismic eye are stimulated to work harder and aim more accurately. Sometimes eye muscle surgery is needed if vision therapy and patching do not yield expected results.” Cheryl Murphy, OD Juan Batlle, MD, Director, Centro Laser, Santo Domingo “Unfortunately the mechanism sometimes going awry, doesn't do well. In children the most common one is congenital ESOTROPIA. These children are born with the eyes turned in. And the reason is 177

that the medial rectus muscle on each side is foreshortened. Therefore the eye is actually turned to the inside. The child will, most of the time, favor one eye and leave the other one turned in. That means that this eye can become lazy and have amblyopia. You don't get amblyopia in both eyes because the brain’s job is to avoid double vision and to avoid anything that will hamper it's ability to function. So the easiest is just to suppress the vision from the turned eye. There is surgery on the medial rectus that will allow us to straighten the eye. The alternative is for the eye to go out. That's called EXOTROPIA. In exotropia again there is surgery on the lateral muscles that will allow us to align and then there are vertical and oblique versions of all these forms of what we know has strabismus. The sooner we deal with strabismus the better the children do. And it's just not a cosmetic problem, it's a functional problem for if we don't learn how we use our two eyes together when we are young we don't develop the third dimension, or stereoscopic vision. You need both eyes in order to have good stereo vision. A child with a ‘lazy’ or amblyoptic eye or with a strabismus, these are the ones that when they go to the theater, with the 3D, they don't see the 3D cause that part of the brain that allows 3D, does not develop and they are not able to perceive in the third dimension.”COLOR BLINDNESSEnChroma Andy Schmeder, President and CEO, 178

“Commonly called color blindness, COLOR VISION DEFICIENCY (CVD) affects about 14 million people in the US, and an estimated 300 million worldwide. Due to an X chromosome defect, 1 in 12 men and 1 in 200 women are CVD. Most with CVD are red-green color deficient. This image below suggests what the red-green see versus a person with normal color vision. “We are familiar with how a magnifying lens makes things appear larger. By making small objects appear larger, one is able to see small details that were previously invisible to the naked eye. What if there was a lens that could magnify the sense of color? What would the world look like through that lens? Think about that for a minute…Color can seem like a mysterious sensation—it is not a tangible thing that you can touch or feel. Color is actually a mental construct that we use to describe how our eyes are responding to the spectrum of light. In fact, our eyes are very crude detectors: there is a great deal of information in the spectrum of light that we cannot see. Using spectral measurements, it is possible to determine the atomic composition of distant stars: the location of 179

certain emission lines in the spectrum give a unique signature indicating the presence of an element such as helium. Yet, our eyes are only able to appreciate stars for their twinkle and give them simple color names like white, yellow, or red.Light in nature can have an infinite variety of spectral content. But when it reaches the retina, the light is encoded into just three channels of information. This is called trichromatic color vision. The “tri” refers to that there are three independent channels that convey color information. The channels correspond to the three types or “classes” of retinal cone cells. Each type responds to a different region of the visible spectrum. Normally the eye is able to distinguish about 1 million distinct shades of color.But, for a person with color vision deficiency, their eye responds to light differently. Typically, two of the types of retinal cone cells have a spectral overlap. Effectively it’s like they only have two and a half channels of information. They only see about 10 percent of those one million colors, or in some cases as few as 1 percent.Remember, there are three cones sensitive to the short, medium and long wavelengths that roughly correspond to blue, green and red. In one type of color blindness, called deutan type, the medium-wavelength cone is spectrally shifted toward longer wavelengths. In essence this cone, which should normally only respond to green line, is seeing into the red part of the spectrum. In the protan type condition, the opposite occurs: the long-wavelength cone is spectrally shifted in the other direction, so the cone normally responsible for red light now sees into the green part of the spectrum. In both cases, we call this condition spectral overlap, and it is the basic underlying cause of common color blindness. Instead of having three independent channels of color information, the overlap yields a visual system with something like two and a half channels, or maybe just two point one in strong cases.” 180

Deutan-type CVD is the most common, about 75% of cases. In deuteranomaly (center above). the sensitivity of the M cone shifts right and acts more like an L cone. If the M cone sensitivity is completely like the L cone, this person is called a deuteranope.Protan-type CVD is the less common, about 25% of cases. In protanomaly (center above). the sensitivity of the L cone shifts left and acts more like an M cone. If the L cone sensitivity is completely like the M cone, this person is called a protananope.Tritan-type CVD is acquired from drug toxicity, disease or trauma and affects the S or blue cone’s sensitivity. For example, in an advanced cataract, where the lens is very yellow/brown, the color blue is significantly changed. People, after cataract surgery often remark not just about how clear they see but how blue, blue is.True colorblindness, called achromatopsia does occur but is extremely rare.”COLOR BLIND ASSISTED 181

SIGHT: The Story of Vision, is the first film to be broadcast with a color correction that is adapted for the vision of people with color blindness. Like Closed Captioning (CC) for the hearing impaired, and Video Description (VD) for low vision and the blind, the color blind accessible correction (CA) helps those with limited red-green color sensitivity better see differences between colors they normally struggle to distinguish. Kris Koenig, SIGHT’s filmmaker worked with EnChroma President and CEO, Andrew Schmeder, to develop a color calibration method to approximate the effect of EnChroma glasses (eyeglasses designed for the individual that is red-green color deficient . Steve Challot, the film’s editor, used the calibration data to implement the correction, which isolates and enhances color along the red-green axis of color space. The result improves the viewing experience for up to 80% of people with red-green color blindness, depending on type and severity. “Color blindness is often considered a mild disability, but can actually have a far reaching impact on a person’s daily life,” said Andrew Schmeder. “The mission of EnChroma is to use our understanding of modern color vision science to produce eyewear for the CVD individual and expand visual experiences for everyone.”COMPLEXITY OF COLOR Ivan Schwab, MD, Professor of Ophthalmology, University of California, Davis 182

“When you talk about color vision the eye has at least three different color receptors. Essentially in the red and the green and the blue range we don't really talk about them like that, we talk about them with numbers but for the stand point of discussing the photo receptors, those cells do the seeing that capture the light and turn it into the signal there are at least three different ones in the eye, in the cones and that's the part of the eye that sees color. But the eye does not see the color. It's in the image to the brain and the brain must compare one signal to another to be able to discern color. If for example you had one color receptor in your eye and some animals like dolphins do have just one color receptor it's in the blue, green range. If you had just one color receptor the brain has nothing to compare it to. You are essentially colorblind even though you would concentrate on those blue, green wavelengths. In order to see color vision you have to have a brain that interprets the three different inputs and compare them one to another. Therefore, the brain is an integral part of sight. Curiously enough, we don't entirely understand where the brain puts it all together. We think of it in what we call the visual cortex, which is at the back of the brain, back of the head. But there may be more to where the eye and the brain puts together movement, where the brain puts together color and lays one part on another. It isn't just a simple as one area either. It's a complex set of steps.” Ivan Schwab MDFLOATERS 183

Image, courtesy of AllAboutVision.comFrom AllAboutVision.com, “Eye floaters are those tiny spots, specks, flecks and \"cobwebs\" that drift aimlessly around in your field of vision. While annoying, ordinary eye floaters and spots are very common and usually aren't cause for alarm.Floaters and spots typically appear when tiny pieces of the eye's gel-like vitreous break loose within the inner back portion of the eye.” Juan Batlle, MD, Director, Centro Laser, Santo Domingo“FLOATERS are due to a few different reasons. The most common ones are the ones we have just due to normal inconsistencies of the gel in the eyes. Your eyeballs are bit like a ping pong ball. And most of that ping pong ball is filled up with something like airplane jelly. And that gel of the eye has little 184

inconsistencies in it. Like sort of nuts in the jelly. As we get older the gel starts to deteriorate.It becomes more liquid and it starts to slosh around like water in a balloon and you start to see these floaters, moving around in your vision.Another important reason that we get floaters is as we get older that gel can actually tug on the retina, damage the retina and cause tears or breakage in the retina itself. These tugs and tears give us very specific symptoms. We'll suddenly get a sudden onset of floaters and or flashing of lights. Typically you see them when you enter a dark room at night. Before you turn the light on people say, ‘oh I thought I saw a flash of lightening‘. This can be a sign that you've got retinal damage due to the vitreous of the eye, the gel of the eye tugging on the retina and tearing it and so in those circumstances you definitely need have an eye examination, using drops in the eye and a very careful look around of the back of the eye to see if you've got any sort of retinal breaks or tears.” 185

CataractsYou probably know someone that has or has had one of these conditions or diseases during their lifetime. Cataracts, glaucoma and age-related macular degeneration are common today in the conversations of so many Americans. Fortunate that life expectancy has reached late 70’s and early 80’s but with that comes changes to the eyes and the body that affects vision. What should you know about each of these, what treatments are effective, what does the future hold and what organizations or agencies provide additional help? CATARACTA cataract is a crystalline lens that is cloudy. The cloudiness is usually a result of the ultraviolet radiation absorbed over a lifetime. This cloudiness blurs vision during the daytime, at night it creates halos around lights and interferes with the ability to drive at night. As the photo at the beginning of this chapter suggests, some children may be born with congenital cataracts A CATARACT IS A CLOUDING OF THE LENS IN YOUR EYE 186

00:00 / 00:00 Source: The National Eye Institute, National Institute of HealthIf you are fortunate to live long enough, you are going to get cataracts. Cataracts are cracks or discolorations in the crystalline lens of the eye that sits behind the iris. You can think of the crystalline lens as the window through which you see the world. When we are born, these lenses are typically crystal clear. Over the course of our lifetime, ultraviolet light causes oxidative damage slowly to these lenses and that is what cataracts are. Cracks or discolorations of the crystalline lens. This is important to know because it happens to nearly everyone if they live long enough. It usually begins when a person is in their 60’s and then slowly progresses until they need cataract surgery sometime in their 70’s. In the US today, one fourth of the population has a significant cataract by age 75.Having a cataract is like driving into the bright headlights of oncoming traffic at night with a very dirty windshield. The light does not come straight through. instead it spreads out sideways and obscures clear vision. During the day, it can add a hazy or cloudy softness that gets progressively worse. 187

Symptoms of cataracts include increased sensitivity to light and glare, a decrease in a person’s best corrected visual acuity and changes in color perception. The eyecare professional will carefully determine what a patient’s best corrected visual acuity is and then examine the crystalline lenses behind the slit lamp biomicroscope to check for cataracts. Recommendations include anti-glare treatment on eyeglass lenses, UV protection to try to prevent further oxidative damage, eating foods rich in anti-oxidant vitamins A, C and E and also a change in glasses prescription if needed. Sometimes cataracts can cause a “myopic shift” meaning a person’s prescription will all the sudden require more minus or less plus power. CATARACTS, 188

THE LEADING CAUSE OF BLINDNESS IN THE DEVELOPING WORLD Dr. Kyle Coffey, President and Board Chair along with Alan Kozarsky MD, Vice President and Medical Director of the ECHO Foundation described the situation common to Honduras that is common to many countries around the world. “The first is a lack of Ophthalmologists locally in Honduras. Therefore, any surgical events require volunteer help. Then, there is the lack of resources, both surgical equipment, and supplies. The final problem is not only common to Honduras but more likely every country in the world and that is a lack of education about cataracts. IN the US, Medicare and other services help to schedule, complete and assist in the payment of a cataract procedure. In Honduras, Dr. Kyle says, “... people in this country just believe that at a certain age you go blind, and you live with it and you let your grandkid, you know, sort of lead you around. They don't know that a ten or fifteen (minute) surgery can fix that problem.” That’s not an uncommon scenario, the challenge for all of us is spreading the word and educating people that if they become cataract blind that it can be fixed. That goes for those in the US as well as the developing world. However, our opportunity to fix this in the developing world would have significant effects on the people, their lives and the economy to which they will contribute.”20 MILLION BLIND WORLDWIDE DUE TO CATARACTS 189

00:00 / 00:00 Ultraviolet damage contributes to the formation of cataracts, its results are unnecessary blindness that can be fixed surgically. Quality sunwear can potentially delay the effects of ultraviolet so that cataracts occur even later in life. When one person is handicapped (from a cataract), at least one other person, must give up what they are doing. Holly Rush, Ivan Schwab MD, Anthony Chapman-Davies, OD, Gullapali Nag Rao, MD, Hon. Bob McMullan, Walter Stark, MD, Alan Kozarsky, MD, Kevin Frick, PhD Alan Kozarsky, MD, Ophthalmologist, The Piedmont Group“For the past 20 years we've done a lot of missions and work with a lot of people down in Honduras. We have a lot of different partners... Our idea is to work with organizations that have a network to bring in the most indigent folks, people that can't take care of their own problems, have no access to medical care. The 190

Lions here in Saint Pedro Sula, at Hospital Fraternidad, have an excellent network of being able to bring people, with advanced cataracts who desperately need eye care, to a place that renders excellent eye care. And they've been our most recent partner over the last half decade and we're, we're thrilled with the progress we've made with them as a partner, trying to eradicate cataract blindness here in Honduras.” These types of events and the medical brigades that the ECHO Foundation creates relies also on those professionals and techs that will travel with them to Honduras. Dr. Kozarsky suggests that the practice of medicine in the United States is difficult and at times less focused on the patient. Dr. Kozarsky says, “ I come down here for the patients. But, a big part of the reason why I come down here is re-centering. It's absolutely re-centering because what we like to do is to take care of people... get out of the United States, go see why you went to medical school in the first place, go see why you did all this training and put it to work here and you're going to help a lot of people, but you're gonna go back a much happier doctor. Dr. Kozarsky sums up the efforts of many like him sharing his skills and time around the world, “Unfortunately for them (people of Honduras), they have advanced disease but you are taking care of them and... It's basically just being the doctor and doing the stuff that you know how to do... there's no extra stuff and you're basically paid in smiles, which is about the best way you can ever get paid”.CATARACT SURGERY 191

Juan Batlle, MD, Director, Centro Laser, Santo Domingo“In cataract surgery several, there are three major operations nowadays, and all three are very good. There are advantages to one over the other. The most commonly performed operation now is called PHACOEMULSIFICATION, in “phaco\" a small probe with a 0.9mm or one millimeter diameter is introduced into the eye to aspirate the crystalline lens. The tip of the phacoemulsifier vibrates at 13,000 hertz. This is fast. And, in doing so it will cavitate, it will make cavities within the crystalline lens and we can disassemble and then aspirate the lens out of the eye. It uses irrigation, aspiration, and ultrasound energy to accomplish this. There is another operation which is actually used in the third world very frequently. Why? Because it's more inexpensive. It is just as fast as the phacoemulsification but the wound is a little bit bigger. In that operation a small incision is created which allows us to remove in total the crystalline lens or cataract out of the eye. There’s cortex around the nucleus of the lens that needs to be washed out and then in its place an artificial lens is introduced. This is known as EXTRACAPSULAR surgery. Recently, and this is thanks to an Israeli ophthalmologist by the name of Blumenthal a small incision, extracapsular operation was developed known as M6 Manual, small incision, cataract surgery. And in this a very small wound, just as you do with phaco, is created and through it you can remove the crystalline lens and introduce the artificial lens as well. New lenses are folded, and are made out of acrylic material that is foldable.” 192

In general, what results can patients expect, recognizing that each patient is different?“In phacoemulsification the wound is only two and a half to three millimeters means that there are no sutures needed. So a suture-less surgery allows introduction a lens through this small wound without having to make it wider also means that recovery is faster. So the first day acuity, the first day after surgery, people will see very well. Then the refraction of the eye will not change because you have not altered the curvature of that cornea. In these cases we can calculate the power of the artificial lens so when we can have them see at distance or read at near without even eye glasses. And, if the lens is a multifocal lens, meaning that it has the property to see at distance and near they won't need any eye glasses for either one. You can choose to have one lens for distance lens and one for near, and since most people nowadays want to be able to do away with their eye glasses all together, this is the way to go for that reason. When you don't have a cataract you can still have the operation as if you were to have a cataract. This is known as phaco refractive surgery and basically you are removing the lens and putting in a multifocal lens or an accommodative lens that will allow you to do both.”Cataract is the most common operation in the world. In part because we have two eyes and we have to be able to operate on both eyes. It's about 99.9% successful. Complication will be an infection which occur very rarely or bleeding which again is very uncommon. Most of the reasons why people don't do well after cataract surgery is because there is a preexisting condition. Either macular degeneration, glaucoma, or something wrong in the retina that may be affecting the final result.”What new technologies are being used?“There is another operation that I didn’t mention but is changing they way cataract surgery is being done and it's really modern. 193

And this is the application of the femtosecond laser to do five of the nine steps that I've mentioned for these procedures without the hand of the surgeon touching the eye. In the femtosecond surgery before going into the operating room, a cone is placed on the eye and the femtosecond will actually divide the nucleus in small pieces and will create a perfect Capsulotomy in the front. The surgeon, then with this phacoemulsifier, aspirates out the contents of the old lens and injects the new lens. Just very safe, much better results, better precision, less suffering for the cornea and this is the way things are probably going to go. CATARACTS, PREVENTABLE, PERHAPS NOT FOR EVERYONE Kevin Frick, PhD, Health Economist, Johns Hopkins, Carey Business School“We've had cataracts surgery in the United States for quite some time with the most modern ways of doing intra-ocular lens replacement rather than people needing to wear special glasses after the cataract surgery. The procedure is not in the tens of dollars but it's also not in the thousands of dollars for a well done 194

procedure and it can be done for people of almost any age with very little risk to the older adults. Our ability to deal with that successfully has changed the lives older adults in terms of driving in the evening, able to drive at all, manage their own lives rather than needing to have their lives managed by children. The interesting question about cataracts is how are we able to bring that to other places around the world. There are some countries where the back log of inoperative cataracts is enormous. Cataracts is not just a condition that causes temporary vision impairment and visual function deficits which can be corrected quite easily (as we can in the US), but instead is something that can cause blindness because there is no one around to do the operation. There are any number of sites around the world where people have come up with very efficient, very effective and very rapid ways of doing the cataract surgery, but there is still so many cases that have remains, is quite a backlog, and actually is a very large cause of blindness.The other interesting thing on the cataract front is thinking about prevention, like wearing sunglasses to avoid UV, and other ways that we can think of to try minimize the risk of cataract. Although even in the US, at some point nearly everyone who lives to 80 years old is going to have at least one cataract removed. In a study I was involved with years ago, we screened nursing home residents for problems with their eye sight and we offered everything that we could do to try and make their access to cataract surgery easier. Many of the residents family members told us, no, Some of the resident said, ‘I really don't want it.’ Even the ophthalmologists in the area said, ‘I don't know why I would operate on somebody who is 90 in a nursing home.’It was interesting to see that there is some population for whom the cataract comes at such a late point in their lives, when there is so many other things that they are dealing with, congestive 195

heart failure, COPD, you know, other chronic conditions that simply getting their eyesight back to a position where they could watch TV better isn't going to make much difference in their overall quality of life. While we see it as something that can be corrected quite easily and quite inexpensively, it remains something that for at least a subset of the population we have to think about, is it the right thing to do for them of all the ways that we could spend money on their well being. RESOURCES WebMD, Cataracts Health Center AllAboutVision.com, Cataracts American Foundation for the Blind, Cataracts LV Prasad Eye Institute That All May Read... National Library Service for the Blind and Physically Handicapped (NLS)Click to add text. You can also drag in images. 196

GlaucomaGLAUCOMA, “SNEAK THIEF OF SIGHT” For a long time, GLAUCOMA has been called the ‘sneak thief of sight’ because it can result in the permanent loss of peripheral vision without pain or symptoms until it is too late.Glaucoma is an increase of pressure within the eye that eventually damages the optic nerve at the optic nerve head. Aqueous humor produced in the ciliary body travels into the anterior chamber through the pupil. If the aqueous cannot drain because the draining system, called the trabecular meshwork, is clogged or closed due to a narrowing, the aqueous is trapped.Production of aqueous continues but there is nowhere for it to drain so it builds up and creates pressure that pushes backwards on the internal structures of the eye. GLAUCOMA 197

00:00 / 00:00 “Glaucoma damages the nerve fibers, blood vessels and the optic nerve. The result is a loss of the peripheral field of view. The photos simulate the encroaching loss of vision at the periphery.” Juan Batlle, MD, Director, Centro Laser, Santo Domingo, James Brandt, MD, Professor of Ophthalmology, University of California, Davis, Anthony Chapman- Davies OD, Associate Professor, University of New South WalesWhat triggers this increase in pressure, or triggers glaucoma?Dr. Chapman-Davies describes glaucoma as, “...a multifactorial disease. It could be normal tension glaucoma, associated with your general vascular status. In other people, it will be directly related to an increase of pressure in the eye. We have a pressure all the time and it's very much like if you're running the faucet and you have the plug out of the sink, the water (aqueous) comes out of the faucet and drains out of the sink. In some people, as we get older the ability of the eye to drain the fluid becomes impaired so it's like putting the plug in and now the fluid starts to accumulate in the eye and the pressure will go up. If the pressure gets to excessive levels, more than the eye can tolerate, then we'll have glaucomatous damage.” The most common type of glaucoma is primary open angle 198

glaucoma and this type is caused by elevated eye pressure going undetected over time. This high eye pressure puts physical pressure on the optic nerve, over time causing damage which results in vision loss. Vision loss typically starts first peripherally. Because little tiny pixels of vision are lost in the periphery first, someone may not notice it until they lose a significant amount of pixels or until vision loss creeps its way toward their central vision. If untreated, significant vision is lost and only clear vision at the center of the field remains. A fields test by a technician, then a look inside the eye and pressure readings by the eye doctor during the eye health exam test for glaucoma. It is critical that these are done to detect the early stages of glaucoma. If there are elevated pressures or the doctor sees evidence of a change to the angle where the drain system occurs, treatment is required. Treatment may include drugs, surgery or a combination of both as well as repeated check-ups. Anthony Chapman-Davies, OD, Associate professor, University of New South Wales 199

“Detection of glaucoma is actually based on a lot of things, not just measuring your eye pressure. And certainly measuring the eye pressure is one of the critical things we do in an eye exam when we're looking for glaucoma because it's also one of the ways we monitor if we're treating glaucoma, is the treatment working? Are we having an effect on pressure? But when we diagnosis glaucoma we need to look at your risk factors. Glaucoma can affect people of any age but normally it affects people who are older. We'll measure your eye pressure but critical to the examination is actually looking at the nerve in the eye itself, because the nerve is what gets damaged. The doctor can then say, “That nerve is normal, has glaucoma or, I'm not to sure.” And, you'll become a glaucoma suspect. If you have glaucoma or are suspect, then we'll do a visual field test to see what your visual world is like. Is the sensitivity of your visual world what it should be for someone of your age? We can also look at some advanced diagnostic technologies like imaging techniques to actually take physical measurements of the optic nerve itself and the surrounding retinal tissue to look for signs of glaucoma or glaucomatous damage.“When Dr. Chapman-Davies was asked, “Can glaucoma be prevented”, with tongue in cheek he replied, “Don’t get old.” The rest of the answer is a prescription for all, “There is no way you can actual prevent glaucoma. The only way that you can really prevent yourself from losing vision from glaucoma is to have regular tests particularly after the age of 40 and especially if you have a family member with the disease. The only way we can treat glaucoma these days is by either putting drops in the eye to lower the pressure or in some patients if the drops are not working, or unsuitable, laser surgery, Iridotomy (a hole lasered through the iris) or physical surgery can help reduce the pressure of the eye.”WHY IS THIS SO IMPORTANT? 200