CONSOLIDATED QUESTION BANK New

ARAVIND EYE HOSPITAL, COIMBATORE DEPARTMENT OF REFRACTION QUESTION BANK 1

CONTENTS S.No CHAPTERS PAGE NO 1 REFRACTION CHAMBER 2 OPTICS 3 VISUAL ACUITY 4 REFRACTIVE ERROR 5 ANISOMETROPIA, ANISEIKONIA & AMBLYOPIA 6 ACCOMMODATION 7 CLINICAL REFRACTION 8 OCULAR MOTALITY 9 VISUAL FIELD 10 ULTASONOGRAPHY (A SCAN) 11 CONTACT LENS 12 LOW VISION 13 DISPENSING OF OPTICS Aravind Eye Care System -Coimbatore

CHAPTER 1 REFRACTION CHAMBER 3

CHAPTER 1 REFRACTION CHAMBER CHAMBER *Equipments needed in refraction chamber • General equipment • Clinical equipment *Equipment’s function and uses: • Occluder • Pinhole • Maddox rod • Stenopic slit • Red And green Flitters • Jackson cross cylinder • Trail frame • Retinoscopy • Phoropter • Auto Refracto meter • Lensometer • PD Ruler scale • RAF ruler • Prism bar • Mydriatics Drugs Cubical • Dimension and Space management in refraction unit • Arrangements. Aravind Eye Care System -Coimbatore

ABBREVIATION 1.NPC - Near point of convergence 2.OS - Ocular sinister 3.OD - Ocular dexter 4.PHVA - Pinhole visual acuity 5.WD - Working distance 6.ADD - Addition 7.JCC - Jackson cross cylinder 8.DP - Diopter 9.PH - Pinhole 10.ARMR - Autorefractometer 11.SS - Stenopic slit 12.MR - Maddox rod 13.RAF - Royal air force ruler 14.PD - Pupillary distance 15.CV - Colour vision 16.PB - Prism bar 17.RC - Refraction chamber 18.HD - Horizontal deviation 19.VD - Vertex distance 20.PM - Plane mirror 21.IPD - Inter pupillary distance 22.MPD - Monocular pupillary distance 23.SR - Streak (or) spot retinoscope 24.NV - Near vision 5

25.TNO - The netherland of ophthalmology 26.BSV - Binocular single vision 27.FR - Fusion range 28.CM - Ciliary muscle 29.SR - Subjective refraction 30.OR - Objective refraction 31.IA - Irregular astigmatism 32.AL - Accessory lens 33.LM - Lensometer 34.SC - Snellen chart 35.ICV - Ishihara colour vision I.FILL IN THE BLANKS 1.Who is the inventor of refraction………. (Willebrord Snell Van Royan). 2.Who is the inventor of Snellen chart……… (Hermann Snellen) 3.A refraction chamber should have ………. illumination room (semi dark room) 4.Refraction cubicle length & width........ (6m, 1 1/2m) 5.Refraction evaluation is done to prescribe suitable glasses for correcting the patient’s............. (vision problems) 6.We use torch light for .............examination (preliminary examination) 7.Adjustable illumination set is mainly used for............assessment(near vision) 8.In trial lens set how many lenses are available........... (228) 9.Spherical lens are available in range from......... (0.12 D to 20.D) 10.Cylindrical lens are available in ranges from.........(0.12 D to 6D) 11.How many accessory lens are available............ (10) 12.How many prisms are available in the trial set............. (0.5D to 12.0) Aravind Eye Care System -Coimbatore

13.All trial lenses are mounted by........... rim with handgrip (plastic or metal) 14.Hand grip are useful for............ (easy handling). 15.In cylindrical lens, axis meridian is indicated by special.......... and comes without handles (marks) 16. Cylindrical lens comes without handle for........... (easy rotation) 17.…….. has its apex & base marked on the lens (prism) 18.Occluder is a..............material disc (opaque disc) 19.Occluder is used to..........(close or cover the eye) 20.Pinhole is used to see ........if there is any improvement in visual acuity(refractive errors) 21.Pinhole actually reduces the.......... (retinal )blur and allows the central light rays to reach the ............ to enhance vision (macula) 22.Pinhole optimum size........... (1.32mm) 23.Multiple pinhole are used when patients is not able to view through the.......... (visual axis) and for patients with...........( low vision) 24.Maddox rod is constructed of a series of......... rods (red cylindrical rods) 25.Maddox rod used to detect.......... (hetrophoria&heterotropia) 26.In maddox rod each rods act as a.......... lens that forms red streak band before the eye (plus cylindrical) 27.Stenopic slit consists of a.............. aperture (rectangular) 28.Stenopic slit width &length.............. (1mm& 15 mm) 29.stenopic slit is useful for refining the........ (axis of high irregular astigmatism) 30.Red & green goggles are mainly used for checking............. (BSV,stereopsis) 31.JCC is used to determine.......... (power & refine the axis verified) 32.JCC is axis of two cylinders are marked in.......... colors (white & red) 33.What is the other name of JCC.......(crosscylinder) 34.JCC consists of.......cylindrical lens (sphero) 35.In JCC white mark are......... lens and red mark are.......... lens (minus & plus) 7

36.Cross cylinder are available in..........powers (0.12d,0.25d,0.50d,1d) 37.Trial frame is constructed of......... number of cells(4) 38.Trial frame is used for keeping the............ lenses (spherical,cylindrical, accessories) 39.Trial frame is consists of........ knobs (3) 40.In trail frame how we place the lens in4 cells ........., ………., ………., ……….(front cell - accessories, second cell -cylinder, third cell – spherical, back cell- high power) 41.In trail frame two eyes frames are being mounted by an adjustable.......... and........(bridge & sides) 42.Special trial frames are available for............. and for during.......... refraction (childrens & low vision) 43.…………..is an objective method (retinoscopy) 44.Retinoscope is to determine the.......... status (refractive status) 45.Retinoscope isused to estimate refractive error for particularly............ (not co-operate child,mentally retarded persons) 46.Two types of Retinoscope are ........., ……… (spot,streak) 47.Other name of phoropter is........... (refractor) 48............... is exclusively designed for refraction (phoropter) 49.Autorefractometer is used to measure the.......... of the eye (refractive power of the eye) 50.Autorefractometer is easily operated even by......... persons (non-technical) 51.Color vision test is done by ............ plates (ishihara) 52.Ishihara color vision plates is used to screen for......... (colorblindness) 53.This chart helps to detect........... deficiencies (red & green) 54.Ishihara chart contains..........number of plates(38) 55.Lensometer is used to........... (measure the corrective lens power) 56.The othername of lensometer is.............. (focimeter) 57.IPD ruler used to measure ....(inter pupillary distance) 58.Inter pupillary distance is.......... in milli meter (distance between the center of two pupil) Aravind Eye Care System -Coimbatore

59.IPD measurements should be obtained for both...........(near& distance) 60.RAF ruler is used to detect the normal range of ............, ……… (convergence&accommodation) 61.What are the two types of prism bars...........? (horizontal&vertical) 62.Prism bars are used to find …….. range (fusionalrange) 63.Horizontal prism bar used to find.......(horizontaldeviation, exo eso) 64.Vertical prism bar usedto find........(vertical deviation, hypo, hyper) 65.Mydriatics causes the............ to dilate(pupil) 66.Mydriatics stimulates........ muscle (iris dilator muscle) 67.Mydriatics is used to facilitate the retinoscopy to the patients having …………(opacityof visual axis) and for…………(fundoscopy) 68.Cycloplegics drugs paralyse..........muscle(iris sphincter muscle) 69.Cycloplegic refraction is important in....... (children) 70.Cycloplegic frequently interferes with.......... refraction (accurate) 71.Expand NPA ........... (near point ofaccommodation) 72.Expand NPC explanation........... (near point of convergence) 73.The cubicle illumination level required is........... (19 foot candles) 74.Patient is seated to........... side (right) of the examiner 75.Trial frame invented by........... (Keelar) 76.Streak retinoscopy invented by........... (Jack C. Copeland) 77.JCC invented........... (William Jackson) 78.Subjective refraction invented.......... (Polanski) 79.Trial frame weight......... (52.9 mgs) 80.What are the two methods of refraction evaluations .......... &.......... (subjective & objective) 81.Plane mirror is used to reflect........... chart at distance (snellen charts) 9

II.Choose the best answer 1.… [a]……is very essential in eye care practice for doing preliminary vision assessment A] Refraction chamber B] snellen’s chart C] retinoscopy 2.A refraction should be done in … [a]… A] Semi dark room B] darkroom C] bright room 3.… [A]….is used to reflect theSnellen chart letters A] Planemirror B] concavemirror C] convex mirror 4. … [A]…..is used for doing the preliminary examination A] Torch light B] ophthalmoscope C] slit lamp 5. … [A]……..is the primary & most essential device in a refraction chamber A] Trial lens set B] concave&convex lens C] accessory lens 6. Trial lens are mounted either by a …[c]…….hand grip for easy handling A] Copper B] iron C] metal(or)plastic 7. Prism has its apex&base marked on the … [a]...…. A] Lens B] handgrip C] trial set 8. Occluder is an opaque disc used to close one eye during … [b]….. A] Fundusexamination B] refractionexamination C] squint examination 9. … [A]…… used to determine the decrease in vision due to refractive error or pathological disease of the eye A] Pinhole B] stenopic slit C] Maddox rod 10. Maddox rod constists of a series of… [b]…… A] Red slit B]red cylindrical rod C]concave&convex cylindrical lens 11. Maddox rod used to detect … [a]……, A] Heterophoria B] refractiveerror C] squint Aravind Eye Care System -Coimbatore

12. Stenopic slit consists of a rectangular aperture with a liner slit of … [a] …width … [a] …. A] 1mmto 15mm B] 2mmto20mm C] 1mm to 3mm 13. … [A]……is used for irregular astigmatism A] Stenopic slit B] sphero cylindrical lens C] placido disc 14. Red &green goggles are used in … [a]….. A] Binocular single vision B] color vision C] duochrome test 15. JCC is a combination of … [a]………power A]minus&plus cylinder B]minus&plus sphere C]cylindrical only 16. The axis of two cylinders in JCC are marked in ….........[b]..........color A] red green B] red white C] white or red 17. …[c]…..is available in 0.12, 0.25, 0.50, and 1.0 power A] Concave lens B] convex lens C] cross cylinder 18. … [A]…… is holding the trial lenses before the eye during refraction A] Trial frame B] trialset C] retinoscopy 19. … [A]……is constructed of three cells on front side &one on back side A] Trialframe B] phoropter C] pediatrics frame 20. The front three surfaces of the trial frame are used for … [a]….. A]spherical,cylindrical,accessories B]prism,JCC,Maddox rod C]stenopic slit,cylindrical,prism 21. The cylindrical lens & the axis are marked …. [c]... A] clock wise B] anti clock wise C] counter clock wise 22. Two eye frames are being mounted by an adjustable … [b]… A] Knobe B] bridge&side C] knobe&bridge 23. The trial frame is adjused depending on the patient’s …[c]….. before starting the refraction test A] Facial asymmetry B] abnormal head posture C] pupillary distance 11

24.........are available for children & for doing low vision refraction A] Special trial frame B] special trial set C] special streak 25. Retinoscope is one of the most essential tools for determining … [a]……objectively A] Refractiveerror B] myopic&hypermetropic error C] astigmatic error 26. … [B]….to estimate the refractive error of those who are unable to co –operate particularly children &mentally retarded person A] Torchlight B] retinoscope C] auto refractometer 27. How many types are available in retinoscope … [b]… A] 1 B] 2 C] 3 28. The streak retinoscope is popular among practitioner because of its.… [A]…. A] Simple&easy B] cosmeticallygood C] expensive 29... [a]……is exclusively designed for refraction A] Phoropter B] Lensometer C] auto refracto meter 30. …[c]…… are comprised ofspherical, cylindrical, prism and all types of auxiliary lenses A] Phoropter B] trial frame C] phoropter&trial frame 31... [a]……..represents the most advanced technology of measuring therefractive power of the eye A] ARMR B] phoropter C] JCC 32. ARMR can be easily operated even by …[c]…. Person A] Technical B] non-technical C] technical &non-technical 33. ARMR provides a quick reliable guideline for the … [a]… refraction A] Objective B] subjective C] subjective&objective 34. … [A]……..are used for screening of color blindness A] Ishiharacolor vision plates B]duchrometest C]binocular vision test 35.Ishihara chart used to detect … [a]……color deficiency A] Red&green B] red&blue C] allcolor Aravind Eye Care System -Coimbatore

36. Ishihara chart contains how many plates…. [A]………. A] 38 B] 15 C] 23 37. How many path way &numbers at ishihara chart…(A)….. A] 13&25 B] 25&13 C] 23&15 38. … [A]...is used for verify lens power A] Lensometer B] autorefractometer C] phoropter 39. Lensometer used to detect the … [a]………power A] sph/cyl/prism B] spherical only C] spherical&cylindrical 40. … [B]……..is provide the dioptric power of convergence &accommodation A] Prism bar B] RAF ruler C] PD ruler III.MATCH THE FOLLOWING 1.REFRACTION EVALUATION - VISION PROBLEM 2.PLANE MIRROR - SNELLEN’S CHART 3.TRIAL FRAME - ESSENTIAL DEVICE 4.NEAR VISION CHART - 33CM-40CM 6M 5.SNELLEN’S CHART3M - FUSION RANGE 6.PRISM BAR - 7.MADDOX ROD - HETEROPHORIA 8.TOPICAL DRUGS - MYDRIATICS 9.ACCESSORY LENS - OCCULUDER 10.CONVEX - PLUS LENS 11.CONCAVE - MINUS LENS 12.STENOPIC SLIT - IRREGULAR ASTIGMATISM 13.OCCULUDER - COVER ONE EYE 14.PINHOLE - ENHANCE VISION 13

15.BASE&APEX - PRISM 16.CYLINDRICAL ROD - MADDOX ROD 17.BSV - RED&GREEN GLASS 18.JCC - POWER&AXIS 19.WHITE MARK - MINUS 20.RED MARK - PLUS 21.PHOROPTER - REFRACTION 22.RETINOSCOPY - MENTALLY RETARDED 23.STREAK RETINOSCOPY- SIMPLE&EASY 24.MYDRIATICS - PUPIL DILATE 25.ISHIHARA CHART - COLOR BLINDNESS 26.LENSOMETER - FOCIMETER 27.PD RULER - NEAR &DISTANCE 28.RAF RULER - CONVERGENCE 29.HOROZONTAL DEVIATION- PRISM 30.CYCLOPLEGIC DROPS - PARALYSIS OF ACCOMMODATION 31.OBJECTIVE REFRACTION- RETINOSCOPY 32.19FOOT CANDLE - 60W 33.SNELLEN’S DRUM - DISTANCE VISION 34.REFRACTIVE ERROR - GLASS PRESCRIPTION 35.ACCURATE REFRACTION- CYCLOPLEGIC DROPS IV.TRUE OR FALSE 1.Vision is very essential in eye care practice for doing preliminary vision assessment -false 2.Refraction cubical arrangement 3cm -6cm-false 3.Streak retinoscope is a general equipment-false Aravind Eye Care System -Coimbatore

4.PD ruler used for pupillary measurement-true 5.Color vision chart is used to detect the color blindness-true 6.Lensometer is used to detect the refractive error-false 7.Maddox rod consists of the cylindrical rod-true 8.Prism has its apex and base marked on the lens-true 9.Occuluder is an opaque disc– true 10.Multiple pinhole is used for low vision patient only-false 11.Maddox rod determines the heterophoria-true 12.Stenopic slit is useful for refining the axis of refractive error-false 13.Red green goggles are used in checking the BSV-true 14.WFDT is used for color vision-false 15.JCC is a spherocylinder-true 16.The trial frame is a metallic frame for holding the trial lens-true 17.Retinoscope is the only device to estimate the refractive error-true 18.Refractor is exclusively designed for refraction-true 19.ARMR is a guideline for the objective refraction-true 20.Lensometer is called as autorefractometer-false 21.PD ruler measurement should be obtained for distance ,for each patient-false V.UNSCRAMBLE WORD 1.REFRACTION - FOTNRCEAOI 2.VISION ASSESSMENT - SISETSVIMSOENAS 3.REFRACTION CHAMBER- IHRRRMEOFTCNBACAE 4.OBJECTIVE - VBEOTJCIE 5.PLANE MIRROR - NOMWPARILE 6.ILLUMINATION - INTLLUONIMAI 15

7.TORCH LIGHT - TLCGIOHTRH 8.TRIAL FRAME - MLTERIAFEA 9.NEAR VISION - OIVIENASNR SENSIOLNLNVIES 10.SNELLEN’S VISION - 11.PROJECTOR - JPTEOCRRO 12.AUTOREFRACTOMETER- AORTOERAFMTUEE 13.OCCULUDER - COCELURDU 14.PINHOLE DISC - DCNPIHLSEOI 15.MADDOX ROD - RDDXDAMOO 16.STENOPIC SLIT - STLECNIOPTSI 17.PRISM LENS - PMESRNILNS 18.COLOR VISION - OOOICNLRISV 19.LENSOMETER - SERLNTEEOM 20.MYDRIATICS - ICYDMRATI 21.MINUS LENS - NISLMEUSN 22.PLUS LENS - SPNEULLS 23.CYLINDRICAL LENS- LYNSELCICNRDLAC 24.SPHERICAL LENS - PEHSARCILNELS 25.ACCESSOR LENS - CNESLCSCARYOE 26.MERIDIAN - AREIDMIN 27.OPTIMUM - MUOPTMI 28.CYLINDRICAL ROD - CNIYLNRIDLACFOR 29.HETEROTROPIA - EPOETTOHRRIA 30.HETEROPHORIA - TPOEHROIHRA 31.IRREGULAR ASTIGMATISM - AMSITGRRIEMGAUTLAIR Aravind Eye Care System -Coimbatore

32.STEREOPSIS - TOESEPSIRSE VI.CORRECT THE SENTENCE 1.Pinhole blurs the image – sharpens 2.Jackson cross cylinder is a combination of cylindrical lens – spherocylinder lens 3.Pinhole is used to occulude one eye – occluder 4.Duochrome test is detect the colour blindness - colour vision 5.Retinoscope used to measure corrective lens power - lensometer 6.Retinoscope is used the only device to estimate the fundus - refractive error. 7.Convex mirror to reflect the snellens chart – plane mirror 8.Torch light is necessory for fundus examination - preliminary 9.Trial set contains the plus and minus lens only – pair of plus and minus sphere and cylinder lens with prism and accessory lens 10.Maddox rod has its apex and base marked on the lens – prism 11.Red and green is used for colour vision test – binocular single vision and stereopsis 12.Pinhole allows the peripheral rays to reach the macula – central 13.Maddox rod measure the amount of fusion – hetero phoria 14.Maddox rod consists of a rectangular aperture – stenopic slit 15.Cycloplegic drops is used to constrict the pupil – dilate 16.Autorefractometer comprised of spherical lens, cylindrical lens prism and all type of auxillary lens – phoropter 17.IPD measurement should be obtainded distance only – near and distance VII.GIVE THE USES FOR THE FOLLOWING INSTRUMENT/TESTS 1.Occuluder - opaque disc used to cover the eye 2.JCC - axis and power verification in cylindrical power 3.Cycloplegic - controls the action of ciliary muscles 17

4.Prism bars - set of prisms with varying power 5.Near visual acuity - sharpness of vision at near point 6.Lensometer - it is used measure the back or front vertex power of a spectacle lens 7.Occluder - opaque disc used to cover the eye 8.Cycloplegics – controls the action of ciliary muscles 9.Reason for vision detect – loss of cone cell VII.GIVE THE REASON 1.Why do we set refraction cubicle dark ANS: To measure the correct refraction power. 2.Why is pinhole used in the refraction ANS: To check the improvement of vision and identify the refractive the refractive error and pothological disease 3.Why do we use ctcloplegic drops for hypermetorpia patient ANS: To relax accommodation 4.Pinhole enhance vision. How? ANS: Allows only the central rays to reach the retina 5.What measurement is used to measure prism power? ANS: Extent of deviation produced as light passes through it 6.What is the use of pseudo ischromatic colour plates? ANS: To evaluate colour vision 7.What type of drops is used to paralyse the ciliary muscles and dilate the pupil? ANS: Cycloplegic drops 8.A pinhole size of 1.32mm is most effective. Why? ANS: It produces the smallest blur circle 9.Why wa are used pinhole for refraction? ANS: There is a limit to pinhole size for clear vision Aravind Eye Care System -Coimbatore

10.Inter pupillary distance should be measured for both the near and distance why? ANS: It is measured the align the center of your eye glass lenses with the center of your eyes properly 11.Why we are using trial frame for refraction? ANS: Trial frame is used for holding the trial lenses during refraction 12.Why we are using stenopic slit ? ANS: It is used to determine the vertex distance and refining the axis of high irregular astigmatism 13.What is used to find the fusional range? ANS : Prism bar is used to find the fusional range 14.What is the other name of retinoscopy? ANS: Skiascopy 15.What are the charts used for near vision? ANS: Jaggers chart is the one type of near vision chart IX.DRAW THE DIAGRAMME 1.Refraction cubicle set up 2.Draw the JCC 3.Draw the occlude and pinhole 4.Draw the maddox rod and stenopic slit 5.Draw the trail frame X.TRANSLATION 1.REFRACTOMETER - ஒளிவிலகல்அளவடீ ்டுகருவி 2.CYLINDRICAL LENS - உருளளவில்ளல 3.PRISM POWER - முப்பட்ளைகஆற்றல் 4.VISUAL ACUITY - காட்சி கூர்ளை 5.PREFERENTIAL LOOKING - முன்னுரிளை தேைல் 19

6.COLOUR VISION - வண்ண பார்ளவ 7.CONGENITAL MYOPIA - பிறவி ைதயாபியா 8.ALTERNATE VISION - ைாற்று பார்ளவ 9.SUBJECTIVE REFRACTION - அகநிளல ஒளிவிலகல் 10.DIPLOPIA -இரட்ை பார்ளவ XI.2MARKS 1.Write about generalequipment for refraction chamber? 2.Write about the clinical equipment for refraction chamber? 3.Define occuluder? 4.Define pinhole? 5.What is Maddox rod? 6.What is stenopic slit? 7.Whatis a use of red &green glass? 8.What is JCC? 9.Define retinoscope 10.What is pohoropter? 11.Write about the ARMR? 12.What is the use of Lensometer? 13.Define color vision? 14.Write about PD ruler scale? 15.Define RAF ruler? 16.What is prism bar? 5MARKS 1.Write about the trial lens box? 2.Write about the trial frame? Aravind Eye Care System -Coimbatore

3.Write about the clinical equipment in refraction chamber? 4.Drawing- refraction chamber 5.Write about the tropical drug and action? 10mark 1.Explained about the equipment needed in refraction chamber? WORKSHEET 1.Write about the various types of pinholes ? 2.How do we measure the amount of hetrotropia ? 3.Explain about the enlarged pinhole ? 4.How do we use the JCC ? 5.Write about the phoropter ? 6.Write about the types of prism bar and uses ? 7.Write about the colour vision chart ? 8.Write about the cubicle dimension ? 9.Write about the difference between PD ruler and RAF ruler ? 10.What are the topical drugs that are used for cycloplegic ? 11.Explain about the advantage of the retinoscope ? 21

CHAPTER 2 OPTICS Aravind Eye Care System -Coimbatore

CHAPTER 2 OPTICS Properties of light • Light travels in a straight line • Reflection • Refraction • Scattering • Interference • Diffraction • Polarisation Laws of reflection • First Law • Second Law Laws Of refraction • First Law • Second Law Refractive index Prism • Prism diopter Types of lens • Biconvex • Plano convex • Meniscus lens( concave & convex) • Biconcave • Plano concave 23

Important terms relating to lens • Optical Centre • Principle axis • Focal point • Focal length • Power of a lens Type of lenses • Concave lens • Convex lens Vergence 1. D Abbreviation 2. - Diopter 3. F - Prism 4. LASER - Far point - light amplification stimulated emission of radiation Aravind Eye Care System -Coimbatore

I.CHOOSE THE BEST ANSWER 1. Light is a form of energy `where interaction with … [A]…..Gives the sensation of light. A] Retina B] cornea C] lens 2. Light is the visible portion of the ……[C]…. Radiation spectrum A] Magnetic B] gravity C] electromagnetic 3. Electromagnetic radiation spectrum lies between ……[C]…. Of ………. A] Ultra-green&blue B]intra red&yellow C]ultra violet&infra-red 4. Wave length of violet spectrum …[A]…… A] 400nm B] 330nm C] 500nm 6. White light consists of ……[C]…. Colors A] 6 B] 5 C] 7 7. In ……[C].. Theory light consist of a stream of tiny particles called which are emitted by a source of light s A] Huygens wave theory B] Einstein quantum theory C] newton theory 8. Particular travel without being affected by earth pulls of produce sensation of light when they enter the eye …………[C]………A] Atom B] proton C] corpuscles 9. Newton’s corpuscular theory explained the phenomenon of propagation of light through …..[C] A] light, refraction B] air, reflection of light C] vacuum, reflection 10. Newton’s corpuscular theory could not explain a number of phenomenon’s such as …[B]….. A] diffraction, refraction, reflection B] interference, diffraction, polarizations C] a,b 11. Newton’s theory corpuscular theory also failed to explain why light travels faster in …[A].. Than material medium A] Vacuum B] water C] lens 12. Huygens proposed that light moves in the form of …[B]… from the luminous source A] Radiation B] wave C] spectrum 25

13. Light wave consists of …….[A]…….. A] crests& troughs B] crests & wave C] particles & crests 14. Trough of crest …[B]……. In shape A] Square B] circular C] rectangular 15.The focus of point in same place at a particular time is called a..[C]… A] Wave length B] wave C] wave front 16. The shape of the wave front depends upon the …[A]….. A] Nature of source B] nature of light C] light waves 17. Waves from a point source in air of the wave front are …[C]…… A] Cylindrical B] spherocylinder C] spherical 18. If the light source is along slit of the wave front are…[A]….. A] Cylindrical B] sphero-cylinder C] spherical 19. An important characteristics of wave motion is that transmits not ………. [A]……… A] energy, matter B] matter, energy C] particle, energy 20. Huygens theory successfully explains phenomenon of ……… and ………[C].. A] diffraction, reflection B] interference, refraction C] interference, diffraction 21. Maxwell proposed light consist of …[B]…… of fields travelling free through vacuum A] magnetic, wave B] electric, magnetic C] spectrum, magnetic 22. Maxwell proposed light is not a ………[C]. Wave A] Electromagnetic B] magnetic C] mechanical 23. Maxwell theory explains the phenomenon related to light satisfactorically but her partial in explaining ………. Fails completely to explain the …[A]….…… effect of light A] scattering, photo chromatic B] scattering, photo chromatic C] a, b Aravind Eye Care System -Coimbatore

24. Einstein proposed that light of a given frequency consist of ….[C]. With same energy A] Neutron B] electron C] photons 25. Photons can be considered the units in which he energy of light ……[A]……. Radiation is measured A] Electromagnetic B] magnetic C] mechanical 27. The energy of photons at ……[A]… is twice as great as that of photons A] 400nm at 800nm B] 500nm to 550nm C] 440nm to 850nm 28. Ultra violet rays produce…[B] A] Injury B] burns C] swelling 29. X rays produce severe damage to [C] A] Skin B] muscle C] tissue 30. ………. And ……….. Also has dual nature [A] A] matter, light B] light, particle C] wave matter 31. Light behaves as ..[B]….. As it passes through air, vacuum or parent ocular tissue A] Wave B] frequency C] magnifier 32. When a light photon is absorbed in one of the sensitive all the ……[C]….… A] Cornea B] lens C] retina 33. A light photon is absorbed in one of the sensitive cell of the retina. The chemical change induces a …. Signal to the brain [C] A] Magnetic B] gravity C] electrical 34. Speed of light in free space is ………[C] A] 3 x 10 m/s B] 4 x 10 m/s C] 3 x 10 m/s 35. Light is transverse in nature of can be ……[A]… A] Polo raised B] transmission C] spectrum 27

36. Light is not reflected by …. Of ….. Fields [C] A] Magnetic B] gravity C] electromagnetic 37. When light pass one meridian to another velocity of wave length change …[C]…. May decreases or remain constant A] Particle B] scattering C] amplitude 38. Colour of light is determined by its …[A]… of not wavelength A] Frequency B] velocity C] amplitude 39. The speed of light in a medium is lesser than in………[C]…. A] Water B] prism C] vacuum 40. Light of a single wavelength is called [B] A] Photo chromatic B] monochromatic C] polo raised 41. White light is ………… [A]… A] Heterochromatic B] photo chromatic C] polo raised 42. The media of the eye are uniformly permeable to the visible rays between …[C]….. Nm A] 400-450nm B] 400-800nm C] 600-390nm 43. Cornea absorbs rays shorter than …[B]….nm A] 600nm B] 295nm C] 335nm 44. The light ray between … [A]…nm only can reach the crystalline lens A] 600-295nm B] 335-350nm C] 400-335nm 45. The normal human eye insensitive to wavelength between [A]….nm A] 400-350nm B] 400-800nm C] 600-390nm 46. In aphakia eyes are sensitive to these wavelengths which give rise to the sensation of …[C]…. ColourA] Red, green B] infract or blue C] blue or violet Aravind Eye Care System -Coimbatore

47. In aphakia eye the ray between [A]….nm can also pass on the retina A] 350-400nm B] 400-800nm C] 600-390nm 48. The human eye can detect energies of a few photons sec up to bright sunlight a difference of ……[C] in sensivityA] 10 B] 8 C] 15 49. The change of brightness necessary to be noticed is …[B].. to the original brightness A] Infinity B] proportional C] a,b 50. A difference is noticed in a bright light source is ……[C]…. than in a dim one A] Equal B] smaller C] larger 51. Wave length is a light wave is defined as the distance between two …[A]. Parts of the wave motion A] Symmetrical B] asymmetrical C] equal 52. Amplitude is a light wave is the …[A]. Displacement of an imaginary particle on the wave from the base line A] Maximum B] minimum C] equal 53. One complete oscillation of light waves is called a …….[B] A] Phase B] cycle C] amplitude 54. Any partition of the cycle is called as …[C].. A] Velocity B] amplitude C] phase 55. Light waves that are out of phase are called … [B]…… A] Coherent B] incoherent C] cycle 56. The light composed of waves exactly in phase is termed …[A]…. A] Coherent B] incoherent C] amplitude 57. The distribution of intensity of light in the region of superimposition is called …….[A]…. A] Interference B] frequency C] intensity 29

58. The wave superimposes their maximum & minimum correspond with each other the resultant intensity is greater than sum of the intensities due to separate wave is called …[A]…. A] constructive interference B] interference C] a,b 59. The wave superimpose the maxima of one correspond with the minima of other the resultant intensity is lesser than the sum of the separate intensities is called ……[A]……. A] destructive interference B] interference C] a,b 60. The best condition for interference to occur is when the light is …[A]……. A] Monochromatic B] photo chromatic C] coherence 61. [C]…… is the measure of the ability of two light beams to produce interference A] Monochromatic B] photo chromatic C] coherence 62. …[A]……. Coherence refers to the ability of two separate portion of the wave to produce interference A] Spatial B] temporal C] nasal 63. …[B]….. Coherence is measured of ability of beam to interference with another portion itself A] Spatial B] temporal C] nasal 64. Temporal coherence is improved by using a filter to select a …[C].. Band of wave length A] Parallel B] equal C] narrow 65. Destructive interference occurs within the ……[C]….. Of the cornea A] Epithelium B] descementsmembrane C] stroma 66. Holography utilizes the phenomenon of interference to produce ……[A]……. Image A] Three dimensional B] one C] two 67. Antireflection coating on the spectacles utilizes principle of … [A]…… A] Destructive B] coherence C] constructive interference Aravind Eye Care System -Coimbatore

68. Excitation filter and the barrier filter used in … [A].. Angiography fundus camera are based on the phenomenon of interference A] Fluorine B] cobalt blue C] dye injection 69. ……[B]…….. Is the most recent introverting clinical application of interference? A] FFA B] OCT C] keratometer 70.The image formed by a plane mirror is ……[b]……. A] Virtual B]virtul& inverted C]virtual&erect 71. Which lens is formed by circle of least diffusioon…..[b]…. A]Cylindrical lens B]Sphero cylindrical lens C]Spherical lens. 72. For a cylindrical lens, the refractive power is incorporated in one axis , other axis has ..... power [B] A]Infinity B]zero C]maximum 73. The distance of the focal point from the optic center is called…..[b]…. A]Principle axis B] focal length C] near point 74. The image formed using a concave lens is…..[a]………… A]Virtual& erect B]virtual & inverted C]real &inverted 75. When light travels from one medium to another deviation is called …….[c]….. A]Reflection B] Incidence C] Refraction 76. The minimum distance at which the light rays reaching the eye are parallel is……….[b]…… A]1m B]6m C] 33cm 77.A convex lens produces a magnified virtual image when an object is placed ……..[c]………. A] at F B]within F and 2F C]within F 31

79. A convex lens acts as a magnifier, when the objects is placed…..[c]…. A] at F B]at 2F C] within f 80.Refractive index of the air is….[a]… A] 0.003 B] 1.0 C]1.5586.The image formed using a concave lens is....[a].... A]Virtual & Erect B]Virtual & Invert C]Real 81.A lens which produces only a virtual image is…..[a]……. A]concave lensB] convex lens C] Cylindrical lens82. The prism effect at the optic center of a lens is ……[c]…… A]+ve B] –veC]zero 83. A prism … White light…..[a]…….A]disperses B]splits C]Spread & Erect. 84.Oneprism diopter, at one meter,produces a shift of ……..[b]…… A] 1 m B]1cm C]1nm II. GIVE THE REASON 1.The refractive index of a medium is always greater than one Speed of light in air is maximum. 2. Concave lens is used to correct myopia To diverge rays and focus on the retina III. CORRECT THE FOLLOWING SENTENCES 1.The colour of any object is determined by the intensity of light.(wavelength) 2.Concave lens always produces real image.(virtual) 3.When light is incident from air to water, the ray will deviate away from the normal (Towards the normal ) 4.In a convex lens, the image moves in the same direction as the object(concave ) 5.The vergence of parallel light is infinity(zero) Aravind Eye Care System -Coimbatore

IV.ANSWER VERY BRIEFLY 1.What is prism power? Displacement of the image of an object located 100cm away from the prism 2.What is the vergence of a parallel beam of light? zero 3. What is the different 33

b. c. 4. What is diffraction? Explain about types of diffraction 5. What are applied aspects of diffraction? Brief explain with diagram Aravind Eye Care System -Coimbatore

IV.STATE TRUE OR FALSE 1.For a spherical lens, the prism power is zero at the optic center [ True ] 2.In a prism , the image is shifted towards the base [ False] 3.Ina prism the image is real [False] 4.In a prism, the image is shifted towards the base [False ] 5.Light travelling in a straight line represents a ray of light [True] 6.Convex lens always produces a real image. [True] 7.In lenses refractive index and thickness are directly proportional to each other [False] 8.Meniscus lens have convex surface in front and concave surface in back. [True] 9. The light travelling through a prism will be bent towards the apex[true] 10.Angle alpha is the angle between the pupillary and visual axis ( False) 11.Angle alpha is usually 5 degree ( True ) 12.Angle alpha is usually positive ( True ) 13.Angle kappa is usually negative ( False ) 14.Light passing through a circular aperture produces a circular diffraction ( True ) 15.Diffrcation effects are minimised by reducing aperture size ( False ) 16.Diffraction is not an important source of aberration in the human eye ( True ) 17.Difraction gratings form the basis of certain potential acuity ( True ) 18.The image formed by a prism is diplaced towards the apex of the prism ( False ) 19.The position of minimu deviation is when the incident ray is perpendicular to the front surface of the prism ( True ) 20.Decentring a convex lens induces image displacement towards the centre of the lens ( False ) 35

21.The refractive index of a lens in air is always greater than its absolute refractive index ( False ) 22. On passing into a medium of greater refractive index , light is deviated towards the interference between the two media ( False ) 23.Snell’s law staes that the angle of incidence divided by the angle of refraction is equal to the change in refractive eindex (True ) 24.A convex spherical curved surface causes parallel light to diverge ( False ) 25.The refracting power of a spherical curved surface in air is equal to its refractive index divided by its radius of curvature.( False ) 26.Prism are used in the assessment of binocular function ( True ) 27.Prism are an found in direct but not indirect opthalmoscope ( False ) 28.Power in prism dioptres is twice the apex angle in degrees ( True ) 29.A compination of base in and base out prism are used to measure vertical deviation ( False ) 30.The angle of incidence is the angle between the incident ray and the reflecting surface ( False ) 31.Refelction at a plane surface produces an erect , real , laterally inverted image ( True ) 32.A convex mirror always produces an erect , virtual , diminished image ( True ) 33.A concave mirror always produces an inverted , real , enlarged image ( True ) 34.Light waves are coherent if they have same frequently and aplitude ( True ) 35.Destructive interference results from the interaction of light waves of opposite phase ( True ) 36.Low refelction coatings depend upon the property of constractive interference ( False ) 37.Destructive interference contributes to the clarity of the cornea ( True ) 38.Wave length of light is inversely proportional to its frequently( True ) Aravind Eye Care System -Coimbatore

V.FILL IN THE BLANKS 1.Positive lenses ……a light beam and negative lenses …… a light beam [converge, diverge ] 2.Principle of antireflection coating is……..[destructive interference] 3.The colour of any object is determined by the ……….[wavelength] of light reflected from the object 4.. ………. [Monochromatic] is consist of a narrow beam of a single wavelength of thus is always coloured a never be white 5.……..[Columniation] all the rays are exactly parallel these properties make it the brightest existing light 6.The distance between the focal point and optic center is called …………[Focal length] 7.Refractive index of glass is the ratio of speed of light into the speed of light in ………[air, glass ] 8.……is a point on the lens where a ray of light passing through it goes straight [optical center ] 9.The clarity of the images formed by optical instruments is limited by …………[diffraction] 10.A ray passing through the ………of a lens does not deviate [optic center] 11.Concave lens produces ……rect and diminished images at all distances [virtual] 12.Prism shifts the image ……… the apex [towards ] 13.The distance of the focal point from the optic center is the……….. [focal length.] 14.Light of a single wave length is called……..[Monochromatic] 15.Other name of Geometrical optics is ……[Ray optics] 16.The white light consists of seven colors denoted by ……[VIBGYOR] 17.White light is…….[ heterochromatic] 37

18.Quantum optics treats light as a ….[particle] 19.Wave optics treats light as a ……[wave] 20.Light with larger wave length is………….[ Red] 21.Light with shorter wave length is….[ blue] 22.Light of a single wave length is ……[monochromatic] 23.The expansion of LASER is …….[light amplification stimulated emission of radiation.] 24.Ray optics is also called ……[Geometrical optics] 25. Franhofer diffraction source of light in………..[ infinity] distance. 26.………….[Polarized] light is used in recording and reproducing three dimension picture in Fresnel diffraction. 27.The behavior of light rays is determined by ………..[ray optics] 28.A group of adjacent divergent (or) convergent rays of light is termed as …[pencil of light] 29.A bundle of light in which the rays (or) arranged in a parallel fashion is termed as……… [ beam of light] 30.The image formed by a convex mirror is always ……[virtual, erect] 31.The laws of refraction also called as…………..[Snellen’s law] 32.The straight line joining the pole and center of curvature is called ……[principle axis] 33.The unit of power is………[ diopter] 34.One diopter is the power of a lens of focal length is ….[one meter] 35.In………[meniscus lens ]the optical center lies outside of the lens. 36.Eye lids acts as …………[shutter of the camera] 37.Iris acts as …………[diaphragm] 38.……..[Corneal portion] separate air from aqueous humour. Aravind Eye Care System -Coimbatore

39.…………[Lens portion] separate aqueous from vitreous humour. 40.Total power of the eye is………[ 60D] 41.Thedioptrically power of the cornea is……….[ 40D] 42.Thedioptrically power of the lens is ………..[20D] 43.The refractive surface tends to be………..[ aspherical] 44.The diameter of the cornea is …[12mm] 45.The refractive index of cornea is….[ 1.37] 46.Therefractive index of air is ….[1] 47.………[Cornea and Lens ]acts as focusing system of the camera. 48.………..[Retina] acts as light sensitivity plate. 49.…….[Choroids] help in forming the dark interior of the camera. 50.The center thickness of cornea is………..[ 0.5mm to 0.6mm] 51.Thedepth of anterior chamber …………[2.5mm to 3.5mm] 52.The diameter of the lens is …..[9mm] 53.………..[Vitreous] gives shape to our eye ball. 54.The central thickness of lens is………[ 3.6mm] 55.The radius of curvature of retina is ……….[12mm] 56.The refractive index of lens is …….[1.42] 57.The…………….[ nodal point] is placed on the posterior surface of the lens. 58.………[Emmetropia] is normal eye. 59.The refractive index of aqueous is ……[1.33] 60.Gulls land’s schematic eye the length is……….[ 24.4mm] 61.Gulls land’s schematic eye corneal thickness is ……….[0.5mm] 39

62.Listing’s reduced eye treats the eye as a ….[single refracting surface] 63.Listing’s reduced eye the second focal point lies on…….[the retina] 64.Light travels in a …….[straight line.] 65.The image formed on a plane mirror is …….[Virtual] 66.Lens diameter in horizontal ……..[4mm] 67.What are the types of spherical mirror ……..[Convex mirror, concave mirror] 68.The distance of the focal point from the optic center if the…………[ focal length] 69. The distance between the optical center and the principal focus………..[focal length] 70.The bending of light rays at the edges of obstrucles its known as……..[polarization,scattering, diffraction]1 71.Human eye can be compared with a………….(camera) 72.The concave lens….[ thin] in centre,…..[ thick] in periphery. 73.The convex lens movement is……….[ against movement] 74.The convex lens is………[ thick] in the center,………..[ thin] in the periphery. 75.A cylindrical lens acts ……..[one axis] 76.The concave lens movement is…………[ with movement] 77.The compound cylindrical is also called ………..[Spherocylinder] 78.The normal visible radiation ………..[400nm – 780nm] 79.Lens diameter in vertical………[ 9mm] 80.Angle between visual axis and pupillary line is called ....... ( Angle kappa ) 81.Angle between optical axis and fixation is called ..... ( Angle coma ) 82. Angle between optical axis and visual axis is called ...... ( Angle alpha ) Aravind Eye Care System -Coimbatore

83.The ........ is the line passing through the centre of the cornea centre of the lens and meets retina .( Optical axis ) 84.The ........ ( crystaline lens ) is a slightly decentred with respect to the visual axis of the eye. 85............ ( Concave mirror ) whose reflecting surface is towards from the centre of the sphere. 86.......... (Convex mirror ) whose reflecting surface is away from the centre of the sphere. 87........ is used to measure the fusional reserve and diagnosis of microtropia .( Prism ) 88.Therapeutically prism are prescribed in patients with ........ ( Phorias & Diplopia ) 89........... is the centre of the reflecting surface .( The pole of the mirror ) VI. EXPLAIN BRIEFLY : 1. Define prism diopter. A prism of 1 D gives an apparent displacement of 1 cm of an object situated at 1 m distance 2. How does laser beam is produces explain 3. The electron delays to a stat lighter than the ground state it will emit a photon is less energetic than the absorbed photon. Therefore a longer wave length called ……. 4. Brief- fluorescein 5. What is transmission of absorption? 6. How does light is measured? 7. Explain luminous flux of luminous intensity? 8. What is illumination of luminance brightness? 9. Draw table principle types of light measurement of their relationship? 10. Brief Apo ship? 11. Define geometrical optics 41

12. What is rectilinear propagation of light with diagram? 13. What is reflection of light of law of reflection explain? 14. Explain types of mirror and image formation in the mirror explain with diagram? 15. How does reflection at an irregular surface explain with diagram? 16. How we calculate the position and magnification of the image formed of the reflection explain 17. What is sign convention? 18. What is refraction of light of laws of refraction explain with diagram 19. Explain total internal reflection of critical angle? 20. What is conditional data of a lens explain label diagram 21.How does refraction at a curved surface? 22. What are the types of lens and explain detail with diagram? 23. Explain cylindrical lens used image formed by cylindrical lens? 24. Explain strums conoid 25. Explain combination of lensed gaurs there? Explain principle focus, principal point, and nodal point 26. What is angular magnification? 27. Explain calculation of the position of magnification of the image formed by lens? 28. What is dioptric power of lenses? 29. Explain Geneva lens measure? 30. Describe optics of eye with diagram 31. What are the components of eye optical system? 32. Explain cornea Aravind Eye Care System -Coimbatore

33. Explain anterior chamber 34. Explain crystalline lens 35. Explain vitreous 36. What are the retinal factors important to image formation? 37. Describe schematic eye 38. What are listings reduced eye its diagram? 39. Brief about retinal image size? 40. What is the image size in ameteropia? 41. What is catoptrics image of explain features of clinical uses of purkinje image 42. Explain axis of visual angles of the eye 43. Is bending of light caused by the edge of an aperture or the rim of a lens? 44. What is diffraction of light? 45. Brief about spherical aberration 46. What is chromatic aberration? 47. What is decantation? 48. What is oblique aberration? 49. What is cornea? Draw a diagram 50. What is prism of refraction through an prism explain 51. How prism used in ophthalmology? 52. What are therapeutic purposes of prism? 53.DRAW : Refraction from a denser medium to rarer medium 53. What is optics? 54. Define light? Light may be defined as an electromagnetic energy level. 43

55. What is a group of convergent (or) divergent rays? (Or) What is pencil of light rays? 56. What is Beam of light rays? A group of parallel light rays is called beam of light rays. 57. Define laws of refraction? Law’s of refraction sini/sinr 58. What is refractive index of air? The refractive index of air is 1 59. What is the refractive index of water? The refractive index of water is 1.33 60. What is the refractive index of glass? The refractive index of glass is 1.52 61. What is uses of prism &lenses in ophthalmology? 62. What is biconvex lens? Biconvex lens are both side convex. 63. What is Plano convex lens? Plano convex lens is one side is plane and other side is convex. 64. What is convex meniscus lens? 65. What does concave lens do 66. What does convex lens do? 67. What are the sources of light? 68. What is the thermal source of light? 69. What is a dioptre? D=1/f 71. What is printice rule? Printice rule p=c*f in cm. 72. What is value of vergence? Vergence value is Zero. 73. What is abbreviation for LASER? Lazer definition light amplification by stimulated emission of radiations. 74. What is the other name of ray optics? 75. How light ray behavior is determined? 76 What is coherence? Aravind Eye Care System -Coimbatore

77. What are the types of coherence? Spatial, Temporal is two type of coherence. 78. What is radiometry? Radiometry is the measurement of light is terms of power the plastic, unit being the watt. 79. What is photometry? Photometry is the measurement of light is units based on the response of the eye. 80. Describe the shape of concave lens? Concave lens is thin in center and thick at the periphery. 81. Describe the shape of convex lens? Convex lens thick in the center and thin at the periphery. 82. What is refractive index of air. 84. What is the reduced eye? Reduced eye 4 cardinal points/ 85. Who invented schematic eye? Schematic eye is invented by Gullstrand. 86. What is regular reflection? When the surface is smooth and polished it is a regular reflection. 87. What happens when surface is not smooth to light? Scattering occurs when the surface is not smooth. 88. What is a law of reflection? The angle of incidence is equal to the angle of reflection in the law’s reflection. 89. What is the image formed in plane mirror? The image formed on a plane mirror is virtual. 45

90. Which mirror is used in refraction cubicles to reduce the length of cubicle? Plane mirror is used in refraction cubicles to reduce the length of the cubicle to half its length. 91. What is the II law of refraction? Law’s at refraction, second law= sini/sinr 92. What is speed of light? The speed of light in air is 1, 80,000m/s.3 x 108 m/s 93. What is the refractive index of diamond? The refractive index of diamond 2.5 94. Magnitude of prism effect depends on which factor? The magnitude of the prism effect depends on the angle of the prism. 95. What is advantage of the large pupil? Advantage of large pupil reducing diffraction. 96. What us catoptrics image? Image formed by the reflecting surfaces of the eye are called catoptrics images. 97. What is absolute refractive index? Absolute refractive index=velocity of light in vacuum. 98. What is refractive index of crown glass? The refractive index crown glass 1.5 99. What is the refractive index of crystalline lens? The refractive index of crystalline lens is 1.42 100. What is the refractive index of contact lens? The refractive index of contact lens is 1.49 Aravind Eye Care System -Coimbatore

101. How is prism power measured? Prism power is measured by the extent of deviation. 102. What is the application of lenses? . Lens application is correcting certain problems in eye sight 103. What are working lenses composed of? .The working lenses consider two prism base to base 104. What is airy disc? The central bright zone is called airy disc. 105. What is optics in prism? Prism makes excellent reflections by total internal reflection 108. Which prism is used in keratometer? Wollsaton prism use in keratometry. 109. What are the types of spherical lenses? The types of spherical lens convex, concave 110. Define 1 ∆? One prism dioptre produces displacement of an object by one cm when kept at a distance of onemetre. 111.What are the uses of prism? 112.What are the uses of small pupil? 113.Draw the diagram plano convex, meniscus convex 114.Draw the diagram plano concave, meniscus concave, biconcave 115.What are the properties of light? 116.How does light travel? 47

117.What are the uses of light? 118.What is the pencil of light rays? 119.What is beam of light rays? 120.What is law’s reflection? 121.What is laws of refraction? 122.What is optics? 123.What is polarization? 124.What is wave optics? 125.What is the diffraction? 126.What are the types of interference? 127.What is nature source of light? 128.What is identification of convex lens? 129. What is uses of convex lens? 130.What is photoelectric effect? VII. Draw the picture: 1.Reflection 2.Refraction WORKSHEET 1.The configuration of rays refracted through a toric surface is called ………… 2.Ophthalmic lenes prescribed for glasses are generally …………shaped ; The front surface …………. And back surface …………… 3 …………………… optics takes into consideration the basic dual nature of light. 4.Laser interferometry is based on ………… Aravind Eye Care System -Coimbatore

5.What is principle for antireflection coating? 6 ……………. Is used for testing stereopsis is based on polarization of light . 7.Hypermetropic patients sees red rays better , myopic sees blue and green rays better what is phenomenon called?/Why does this occurs ? 8.Posterior focal length …………. 9.Changes in lens during accommodation have been studied using the …………….. purkinje image 10.Clinical use of purkinje sames on image is in ………… and…………….. CHAPTER 3 VISUAL ACUITY 49

CHAPTER 3 VISUAL ACUITY Standerd Of Visual acuity Principle of Snellens chart Types of visual acuity • Distance visual acuity • Near visual acuity • Pinhole visual acuity Various Distant Visual acuity charts In adults • Snellens Chart • ETDRS chart IN Illiteraters Aravind Eye Care System -Coimbatore