QUESTION BANK FINAL

51 Ans : A . Coherent 57. The distribution of intensity of light in the region of superimposition is called …….…. A] Interference B] frequency C] intensity Ans : A . Interference 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] constructive interference B] interference C] a,b Ans : A . constructive interference 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] destructive interference B] interference C] a,b Ans : A . destructive interference 60. The best condition for interference to occur is when the light is ………. A] Monochromatic B] photo chromatic C] coherence Ans : A . Monochromatic 61. …… is the measure of the ability of two light beams to produce interference A] Monochromatic B] photo chromatic C] coherence REFRACTION DEPARTMENT-CBE

52 Ans : C . coherence 62. ………. Coherence refers to the ability of two separate portion of the wave to produce interference A] Spatial B] temporal C] nasal Ans : A . Spatial 63. …….. Coherence is measured of ability of beam to interference with another portion itself A] Spatial B] temporal C] nasal Ans : B . temporal 64. Temporal coherence is improved by using a filter to select a ….. band of wave length A] Parallel B] equal C] narrow Ans : C . narrow 65. Destructive interference occurs within the ……….. Of the cornea A] Epithelium B] descementsmembrane C] stroma Ans : C . stroma 66. Holography utilizes the phenomenon of interference to produce …………. Image A] Three dimensional B] one C] two Ans : A . Three dimensional 67. Antireflection coating on the spectacles utilizes principle of … ……

53 A] Destructive B] coherence C] constructive interference Ans : A . Destructive 68. Excitation filter and the barrier filter used in … ..angiography fundus camera are based on the phenomenon of interference A] Flurosin B] cobalt blue C] dye injection Ans : A . Flurosin 69. ………….. Is the most recent introverting clinical application of interference? A] FFA B] OCT C] keratometer Ans : B . OCT 70.The image formed by a plane mirror is …………. A] Virtual B]virtul& inverted C]virtual&erect Ans : B . virtul& inverted 71. Which lens is formed by circle of least diffusion…..…. A]Cylindrical lens B]Sphero cylindrical lens C]Spherical lens Ans : B . Sphero cylindrical lens 72. For a cylindrical lens, the refractive power is incorporated in one axis , other axis has ..... power A]Infinity B]zero C]maximum Ans : B . zero 73. The distance of the focal point from the optic center is called…..…. REFRACTION DEPARTMENT-CBE

54 A]Principle axis B] focal length C] near point Ans : B. focal length 74. The image formed using a concave lens is…..………… A]Virtual& erect B]virtual & inverted C]real &inverted Ans : A . Virtual & erect 75. When light travels from one medium to another deviation is called …….….. A]Reflection B] Incidence C] Refraction Ans : C . Refraction 76. The minimum distance at which the light rays reaching the eye are parallel is……….…… A]1m B]6m C] 33cm Ans : B . 6m 77.A convex lens produces a magnified virtual image when an object is placed ……..………. A] at F B]within F and 2F C]within F Ans : C . within F 79. A convex lens acts as a magnifier, when the objects is placed…..…. A] at F B]at 2F C] within f Ans :C. within f 80.Refractive index of the air is….… A] 0.003 B] 1.0 C]1.55

55 Ans : A . 0.003 81.A lens which produces only a virtual image is…..……. A]concave lens B] convex lens C] Cylindrical lens Ans :A . concave lens 82. The prism effect at the optic center of a lens is ………… A]+ve B] –ve C]zero Ans :C . zero 83. A prism … White light A]disperses B]splits C]Spread Ans :A . disperses 84.Oneprism diopter, at one meter,produces a shift of ……..…… A] 1 m B]1cm C]1nm Ans :B . 1cm 85.The image formed using a concave lens is....... A]Virtual & Erect B]Virtual & Invert C]Real Ans : A . Virtual & Erect II. GIVE THE REASON: 1.The refractive index of a medium is always greater than one REFRACTION DEPARTMENT-CBE

56 Ans : Speed of light in air is maximum 2. Concave lens is used to correct myopia Ans :To diverge rays and focus on the retina III. CORRECT THE FOLLOWING SENTENCES : 1.Thecolour of any object is determined by the intensity of light. Ans : Wavelength 2.Concave lens always produces real image. Ans : virtual 3.When light is incident from air to water, the ray will deviate away from the normal Ans : Towards the normal 4.In a convex lens, the image moves in the same direction as the object Ans : Concave 5.Thevergence of parallel light is infinity Ans : zero IV.ANSWER VERY BRIEFLY 1.What is prism power?

57 Ans : Displacement of the image of an object located 100cm away from the prism 2.What is the vergence of a parallel beam of light? Ans : zero 3. What is the different REFRACTION DEPARTMENT-CBE

58 B. Draw a diagram of prism refraction . .. 4. Whatis diffraction? Explain about types of diffraction 5. What are applied aspects of diffraction? Brief explain with diagram IV. STATE TRUE OR FALSE :

59 1. For a spherical lens, the prism power is zero at the optic center 2. In a prism , the image is shifted towards the base Ans : True 3. Ina prism the image is real Ans : False 4. In a prism, the image is shifted towards the base Ans : False Ans : False 5. Light travelling in a straight line represents a ray of light Ans : True 6. Convex lens always produces a real image. Ans : True 7. In lenses refractive index and thickness are directly proportional to each other Ans : False 8. Meniscus lens have convex surface in front and concave surface in back. Ans : True 9. The light travelling through a prism will be bent towards the apex Ans : True 10. Angle alpha is the angle between the pupillary and visual axis Ans : False REFRACTION DEPARTMENT-CBE

60 11. Angle alpha is usually 5 degree Ans : True 12. Angle alpha is usually positive Ans : True 13. Angle kappa is usually negative Ans : False 14. Light passing through a circular aperture produces a circular diffraction Ans : True 15. Diffraction effects are minimized by reducing aperture size Ans : False 16. Diffraction is not an important source of aberration in the human eye Ans : True 17. Difraction gratings form the basis of certain potential acuity Ans : True 18. The image formed by a prism is displaced towards the apex of the prism Ans : False 19. The position of minimum deviation is when the incident ray is perpendicular to the front surface of the prism Ans : True 20. Decentering a convex lens induces image displacement towards the centre of the lens

61 Ans : False 21.The refractive index of a lens in air is always greater than its absolute refractive index Ans : False 22. On passing into a medium of greater refractive index , light is deviated towards the interference between the two media Ans : False 23. Snell’s law stages that the angle of incidence divided by the angle of refraction is equal to the change in refractive index Ans : True 24. A convex spherical curved surface causes parallel light to diverge Ans : False 25.The refracting power of a spherical curved surface in air is equal to its refractive index divided by its radius of curvature. 26. Prism are used in the assessment of binocular function Ans : False 27. Prism are an found in direct but not indirect opthalmoscope Ans : True 28. Power in prism dioptres is twice the apex angle in degrees Ans : False Ans : True REFRACTION DEPARTMENT-CBE

62 29. A compination of base in and base out prism are used to measure vertical deviation Ans : False 30. The angle of incidence is the angle between the incident ray and the reflecting surface Ans : False 31. Reflection at a plane surface produces an erect , real , laterally inverted image Ans : True 32. A convex mirror always produces an erect , virtual , diminished image Ans : True 33. A concave mirror always produces an inverted , real , enlarged image Ans : True 34. Light waves are coherent if they have same frequently and amplitude Ans : True 35. Destructive interference results from the interaction of light waves of opposite phase Ans : True 36. Reflection coatings depend upon the property of constructive interference Ans : False 37. Destructive interference contributes to the clarity of the cornea Ans : True

63 38. Wave length of light is inversely proportional to its frequency Ans : True V. FILL IN THE BLANKS : 1.Positive lenses ……a light beam and negative lenses …… a light beam Ans : converge, diverge 2.Principle of antireflection coating is…….. Ans : destructive interference 3.The colour of any object is determined by the ………. of light reflected from the object Ans : wavelength 4.. ………. is light is light radiation where optical spectrum contains only single optical frequency Ans : Monochromatic 5.…….. all the rays are exactly parallel these properties make it the brightest existing light Ans : Columniation 6.The distance between the focal point and optic center is called ……………… Ans : Focal length 7.Refractive index of glass is the ratio of speed of light in …… speed of light in ……… Ans : air, glass REFRACTION DEPARTMENT-CBE

64 8.……is a point on the lens where a ray of light passing through it goes straight Ans : optical center 9.The clarity of the images formed by optical instruments is limited by ………… Ans : diffraction 10.A ray passing through the ………of a lens does not deviate Ans : optic center 11.Concave lens produces ……rectand diminished images at all distances Ans :virtual 12.Prism shifts the image ……… the apex Ans : towards 13.The distance of the focal point from the optic center is the……….. Ans : focal length. 14.Light of a single wave length is called……. Ans : Monochromatic 15.Other name of Geometrical optics is …… Ans : Ray optics 16.The white light consists of seven colors denoted by …… Ans : VIBGYOR

65 17.White light is…… 18.Quantum optics treats light as a … Ans : heterochromatic 19.Wave optics treats light as a …… Ans :particle 20.Light with larger wave length is………… Ans : wave Ans : Red 21.Light with shorter wave length is…. Ans : blue 22.Light of a single wave length is …… Ans :monochromatic 23.The expansion of LASER is ……. Ans : Light Amplification Stimulated Emission Of Radiation 24.Ray optics is also called …… Ans : Geometrical optics 25. Franhofer diffraction source of lightis in……….. Ans : infinity distance. REFRACTION DEPARTMENT-CBE

66 26.………… light is used in recording and reproducing three dimension picture in Fresnel diffraction. Ans :Polarized 27.The behavior of light rays is determined by ……….. Ans : ray optics 28.A group of adjacent divergent (or) convergent rays of light is termed as ……… Ans : pencil of light 29.A bundle of light in which the rays (or) arranged in a parallel fashion is termed as……… Ans : beam of light 30.The image formed by a convex mirror is always …… Ans : virtual, erect 31.The laws of refraction also called as………….. Ans : Snellen’s law 32.The straight line joining the pole and center of curvature is called …… Ans : principle axis 33.The unit of power is……… Ans : diopter 34. If power of lens is diopter its focal length is ……. Ans : one meter 35.In……… the optical center lies outside of the lens.

67 Ans :meniscus lens 36.Eye lids acts as ………… Ans : shutter of the camera 37.Iris acts as ………… Ans: diaphragm 38.…….. separate air from aqueous humour. Ans : Corneal portion 39.………… separate aqueous from vitreous humour. Ans : Lens portion 40.Total power of the eye is……… Ans :Lens portion 41.Thedioptrical power of the cornea is………. 42.Thedioptrical power of the lens is ……….. Ans : 40D 43.The refractive surface tends to be……….. Ans : 20D 44.The diameter of the cornea is ……… Ans : aspherical Ans : 12mm REFRACTION DEPARTMENT-CBE

68 45.The refractive index of cornea is…. Ans : 1.37 46.Therefractive index of air is … Ans :1 47.……… acts as focusing system of the camera. 48.……….. acts as light sensitivity plate. Ans : Cornea and Lens Ans : Retina 49.……. help in forming the dark interior of the camera. Ans : Choroids 50.The center thickness of cornea is……….. Ans : 0.5mm to 0.6mm 51.Thedepth of anterior chamber ………… Ans : 2.5mm to 3.5mm 52.The diameter of the lens is ….. Ans : 9mm 53.……….. gives shape to our eye ball. 54.The central thickness of lens is……… Ans : Vitreous 55.The radius of curvature of retina is ……… Ans : 3.6mm

69 Ans :12mm 56.The refractive index of lens is …… Ans :1.42 57.The……………. is placed on the posterior surface of the lens. Ans : nodal point 58.……… is normal eye. Ans :Emmetropia 59.The refractive index of aqueous is …… Ans : 1.33 60.Gulls land’s schematic eye the length is……… Ans :24.4mm 61.Gulls land’s schematic eye corneal thickness is ……… Ans :0.5mm 62.Listing’s reduced eye treats the eye as a …. Ans : single refracting surface 63.Listing’s reduced eye the second focal point lies on…… Ans :the retina 64.Light travels in a …… Ans :straight line REFRACTION DEPARTMENT-CBE

70 65.The image formed on a plane mirror is ……. Ans : Virtual 66.Horizontal lens diameter is …….. Ans : 4mm 67.What are the types of spherical mirror …….. Ans : Convex mirror, concave mirror 68.The distance of the focal point from the optic center if the………… Ans : focal length 69. The distance between the optical center and the principal focus……….. Ans : focal length 70.The bending of light rays at the edges of obstrucles its known as……. Ans : diffraction 71.Human eye can be compared with a…………. Ans :camera 72.The concave lens……… in centre,….. in periphery. 73.The convex lens movement is………. Ans : thin , thick Ans : against movement

71 74.The convex lens is………in the center,……….. in the periphery. 75.A cylindrical lens acts in……. Ans : thick , thin 76.The concave lens movement is………… Ans :one axis 77.The compound cylindrical is also called ……….. 78.The normal visible radiation ……….. Ans : with movement 79. Vertical diameter of lens is ……… Ans :Spherocylinder Ans : 400nm – 780nm Ans : 9mm 80.Angle between visual axis and pupillary line is called ....... Ans : Angle kappa 81.Angle between optical axis and fixation is called ..... Ans : Angle coma 82. Angle between optical axis and visual axis is called ...... Ans : Angle alpha REFRACTION DEPARTMENT-CBE

72 83.The ........ is the line passing through the centre of the cornea centre of the lens and meets retina . Ans : Optical axis 84.The ........ is a slightly decentred with respect to the visual axis of the eye. Ans :crystaline lens 85............whose reflecting surface is towards from the centre of the sphere. Ans : Concave mirror 86.......... whose reflecting surface is away from the centre of the sphere. Ans : Convex mirror 87........ is used to measure the fusional reserve and diagnosis of microtropia Ans : Prism 88.Therapeutically prism are prescribed in patients with ........ Ans :Phorias& Diplopia 89........... is the centre of the reflecting surface . Ans : The pole of the mirror VI. EXPLAIN BRIEFLY : 1. Define prism diopter.

73 Page no : 9 ( Manual ) 2. What is uses of convex lens? Page no : 22 ( Khurana ) 3.What is photoelectric effect? Page no : 10 ( Khurana ) 4. Brief- fluorescein Page no :10 ( Khurana ) 5. What is transmission of absorption? Page no : 13 ( Khurana ) 6. How is light measured? Page no : 13 ( Khurana ) 7. Explain luminous flux of luminous intensity? Page no : 13 ( Khurana ) 8. What is illumination of luminance brightness? Page no : 13 ( Khurana ) 9. Draw table principle types of light measurement of their relationship? Page no : 13 ( Khurana ) 10. Brief Apo ship? Page no : 13 ( Khurana ) REFRACTION DEPARTMENT-CBE

74 11. Define geometrical optics Page no : 14 ( Khurana ) 12. What is rectilinear propagation of light with diagram? Page no : 14 ( Khurana ) 13. What is reflection of light of law of reflection explain? Page no : 14-15 (Khurana ) 14. Explain types of mirror and image formation in the mirror explain with diagram? Page no : 16 ( Khurana ) 15. How does reflectionoccur at an irregular surface explain with diagram? Page no : 16 ( Khurana ) 16. How we calculate the position and magnification of the image formed of the reflection explain Page no : 17 ( Khurana ) 17. What is sign convention? Page no : 17-18 ( Khurana ) 18. What is refraction of light laws of refraction explain with diagram Page no : 18 ( Khurana ) 19. Explain total internal reflection critical angle? Page no : 18 ( Khurana ) 20. What is conditional data of a lens explain label diagram

75 Page no : 20 ( Khurana ) 21.How does refraction occur at a curved surface? Page no : 21 ( Khurana ) 22. What are the types of lens and explain detail with diagram? Page no : 22 ( Khurana ) 23. Explain cylindrical lens image formation by cylindrical lens? Page no : 13 ( Khurana ) 24. Explain strums conoid Page no : 24 ( Khurana ) 25. Explain principle focus, principal point, and nodal point Page no : 26 ( Khurana ) 26. What is angular magnification? Page no : 26 ( Khurana ) 27. Explain calculation of the position of magnification of the image formed by lens? Page no : 26 ( Khurana ) 28. What is dioptric power of lenses? Page no : 26 ( Khurana ) 29. Explain Geneva lens measure? REFRACTION DEPARTMENT-CBE

76 Page no : 28 ( Khurana ) 30. Describe optics of eye with diagram Page no : 28 ( Khurana ) 31. What are the components of eye optical system? Page no : 29 ( Khurana ) 32. Explain cornea Page no :29 ( Khurana ) 33. Explain anterior chamber Page no :30 ( Khurana ) 34. Explain crystalline lens Page no :30 ( Khurana ) 35. Explain vitreous Page no :31 ( Khurana ) 36. What are the retinal factors important for image formation? Page no : 31 ( Khurana ) 37. Describe schematic eye Page no :31 ( Khurana ) 38. What are listings reduced eye its diagram? Page no :31 ( Khurana )

77 39. Brief about retinal image size? Page no :34 ( Khurana ) 40. What is the image size in ameteropia? Page no :34 ( Khurana ) 41. What is catoptrics image ? Explain features & clinical uses of purkinje images Page no :35 ( Khurana ) 42. Explain axis of visual angles of the eye Page no :35 ( Khurana ) 43. Is bending of light caused by the edge of an aperture or the rim of a lens? Page no :36 ( Khurana ) 44. What is diffraction of light? Page no :36 ( Khurana ) 45. Brief about spherical aberration Page no :36 ( Khurana ) 46. What is chromatic aberration? Page no :37 ( Khurana ) 47. What is decentration? Page no :37 ( Khurana ) 48. What is oblique aberration? REFRACTION DEPARTMENT-CBE

78 Page no :37 ( Khurana ) 49. What is cornea? Draw a diagram Page no : 4 ( Basak ) 50. What is prism of refraction through an prism explain Page no : 19 ( Khurana ) 51. How prism used in ophthalmology? Page no : 19 ( Khurana ) 52. What are therapeutic purposes of prism? Page no : 19 ( Khurana ) 53.DRAW : Refraction from a denser medium to rarer medium Page no : 13 ( Khurana ) 53. What is optics? Page no : 8 ( Manual ) 54. Define light. Light may be defined as an electromagnetic energy level. Page no :1 ( Khurana ) 55. What is a group of convergent (or) divergent rays? (Or) What is pencil of light rays? Page no :1( Khurana ) 56. What is Beam of light rays? Page no :1( Khurana )

79 57. Define laws of refraction? Page no :9 (Manual ) 58. What is refractive index of air? Page no :59 ( Basak ) 59. What is the refractive index of water? Page no :59 ( Basak ) 60. What is the refractive index of glass? Page no :59 ( Basak) 61. What are the uses of prism &lenses in ophthalmology? Page no : 19 ( Khurana ) 62. What is biconvex lens? Page no :9 (Manual ) 63. What is Plano convex lens? 64. What is convex meniscus lens? Page no :9 ( Manual ) 65. What does concave lens do Page no :9 (Manual) 66. What does convex lens do? Page no : 13 ( Khurana ) REFRACTION DEPARTMENT-CBE

80 Page no : 13 ( Khurana ) Page no : 13 ( Khurana ) 67. What are the sources of light? Page no : 13 ( Khurana ) 68. What is the thermal source of light? Page no : 13 ( Khurana ) 69. What is a dioptre? D=1/f Page no : 13 ( Khurana ) 71. What is printice rule? Page no : 13 ( Khurana ) 72. What is value of vergence? Page no : 13 ( Khurana ) 73. What is abbreviation for LASER? Page no : 13 ( Khurana ) 74. What is the other name of ray optics? Page no : 13 ( Khurana ) 75. How light ray behavior is determined? Page no : 13 ( Khurana ) 76 What is coherence? 77. What are the types of coherence?

81 78. What is radiometry? Page no : 13 ( Khurana ) 79. What is photometry? Page no : 13 ( Khurana ) 80. Describe the shape of concave lens? Page no : 13 ( Khurana ) 81. Describe the shape of convex lens? Page no : 13 ( Khurana ) 82. What is refractive index of air. Page no : 13 ( Khurana ) 84. What is the reduced eye? Page no : 13 ( Khurana ) 85. Who invented schematic eye? Page no : 13 ( Khurana ) Page no : 13 ( Khurana ) 86. What is regular reflection? Page no : 13 ( Khurana ) 87. What happens when surface is not smooth to light? Page no : 13 ( Khurana ) 88. What is a law of reflection? REFRACTION DEPARTMENT-CBE

82 Page no :8 (Manual) 89. What is the image formed in plane mirror? Page no :128 ( Khurana ) 90. Which mirror is used in refraction cubicles to reduce the length of cubicle? 91. What is the II law of refraction? Page no :8 ( Manual ) 92. What is speed of light? Page no :8 (Manual ) 93. What is the refractive index of diamond? Page no : 13 ( Khurana ) 94. Magnitude of prism effect depends on which factor? Page no : 13 ( Khurana ) 95. What is advantage of the large pupil? 96. What us catoptrics image? Page no : 13 ( Khurana ) 97. What is absolute refractive index? Page no :35 ( Khurana ) 98. What is refractive index of crown glass? Page no : 13 ( Khurana )

99. What is the refractive index of crystalline lens? 83 100. What is the refractive index of contact lens? 101. How is prism power measured? Page no :59 ( Basak ) 102. What is the application of lenses? Page no :59 (Basak) 103. What are working lenses composed of? Page no : 13 ( Khurana ) 104. What is airy disc? Page no :110 ( Manual ) 105. What is optics in prism? Page no : 13 ( Khurana ) 108. Which prism is used in keratometer? Page no :49 ( Manual ) 109. What are the types of spherical lenses? Page no :8 ( Khurana ) 110. Define 1 ∆? Page no :9 ( Khurana ) Page no : 13 ( Khurana ) Page no : 13 ( Khurana ) REFRACTION DEPARTMENT-CBE

84 Page no :9 ( Manual ) 111.What are the uses of prism? Page no :9 ( Manual ) 112.What are the uses of small pupil? Page no :107 ( Basak) 113.Draw the diagram forplano convex, meniscus convex Page no : 9 ( Manual ) 114.Draw the diagram for plano concave, meniscus concave, biconcave 115.What are the properties of light? Page no :8 ( Manual ) 116.How does light travel? Page no :8 ( Manual ) 117.What are the uses of light? Page no :8 (Manual) 118.What is the pencil of light rays? Page no :2 ( Khurana ) 119.What is beam of light rays? Page no :8 (Manual ) 120.What is law’s reflection? Page no :8 (Manual)

121.What is the laws of refraction? 85 122.What is optics? 123.What is polarization? Page no :8 (Manual) 124.What is wave optics? Page no :8 ( Manual ) 125.What is the diffraction? Page no :12 ( Manual ) 126.What are the types of interference? Page no :12 (Manual ) 127.What is nature source of light? Page no :12 ( Manual ) 128.How to identification of convex lens? Page no :12 ( Manual ) Page no : 13 ( Khurana ) VII. DRAW THE PICTURE: Page no :22 ( Khurana ) 1.Reflection 2.Refraction REFRACTION DEPARTMENT-CBE

86 VIII. MATCH THE FOLLOWING : 1. Study of light - Triangular piece 2. Prism - Optics 3. Converge lens - Convex 4. Minus lens - Concave 5. Base to Base -1 6. Apex to Apex - 1.5 7. Lens - 1.33 Refractive index of - Plus lens 8. Air - Diverge lens Refractive index of Transparent 9. Water - medium Refractive index of 10. Glass IX. JUMBING WORDS : 1. –EC-N—A-I-- - Divergence 2. –EN-IC—U-E - Prentice rule 3. –OL—I-A-ION - Polarisation 4. –E—ENC- - Vergence Converging 5. C-N-ERG---- X.UNSCRAMBLE WORDS: 1. XEDNIREFEVITAR - Refractive index 2. SNELSUCSINME - Meniscus lens 3. NSELEVACNOC - Concave lens

87 4. RALUGNAIRT - Triangular Positive vergence 5. ECNEGREVVEITISOP - WORKSHEET 1.The configuration of rays refracted through a toric surface is called ………… 2.Ophthalmic lens prescribed for glasses are generally …………shaped 3 …………… optics takes into consideration the basic dual nature of light. 4.Laser interferometry is based on ………… 5.What is principle for antireflection coating? REFRACTION DEPARTMENT-CBE

88 6 ………Is used for testing stereopsis and 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.Changes in lens during accommodation have been studied using the …………….. purkinje image

89 CHAPTER 3 VISUAL ACUITY REFRACTION DEPARTMENT-CBE

90 CHAPTER 3 VISUAL ACUITY CONTENTS Standard Of Visual acuity Principle of Snellen’s chart Types of visual acuity • Distance visual acuity • Near visual acuity • Pinhole visual acuity Various Distant Visual acuity charts In adults • Snellen’s Chart • ETDRS chart IN Illiterates • E chart • Landolts broken ring chart

91 • Mutiple picture chart In Children • Cake Decoration • Teller Acuity Charts • Allen Picture Chats • Sheridan Gardiner test • Keelers Prefertial looking Test • Cardiff Charts I. ABBREVIATION 1. VA - Visual acuity 2. OD - Ocular Dexter 3. OS - Ocular sinister 4. CC - Cum correction 5. PH - Pinhole 6. PR - Projection of rays 7. PL - Perception of light 8. FCF - Finger counting close to face 9. NOPL - No light perception 10. OKN - Opto Kinetic Nystagmus. 11. PLT . - Preferential Looking Test 12. TAFC - Two Alternative forced choice. 13. OPL - Operant Variation test. 14. TAC - Teller Acuity Chart REFRACTION DEPARTMENT-CBE

92 - Visually Evoked Response - Matching Test 15. VER - Vanishing Optotype 16. MT - Hand Movement 17. VO - Sheridan Gartiner Test 18. HM - Allen Picture Card 19. SGT - Cardiff Card,Cross Cylinder 20. APC 21. CC Early Treatment Diabetic Retinopathy Of - Study 22. ETDRS - Pinhole Visual Acuity 23. PVA - Landolt’s Broken Ring Chart 24. LBRC - Multible Picture Chart 25. MPC - Cake Decoration 26. CD - Opto Kinetic Nistagmus 27. OKN II.CHOOSE THE BEST ANSWER: 1. Acuity of vision is defined as the power of the eye to see .......... Object A] Smallest B] biggest Ans : A] Smallest 2. Visual acuity is the medical term for.............. Of vision A] Dimness B] sharpness

93 Ans : B] sharpness 4.Vision should be tested with and without glasses on a....... Chart A] Snellens B] Ishihara chart Ans : A] Snellens 5.Visual acuity Should be tested................ independently A] Each eye B] both eye Ans : A] Each eye 6. A normal eye can easily distinguish two points separated by an angle of........... To the eye A] two minute B] one minute Ans : B] one minute 7. Perfect acuity o vision requires two other basic factors the.......... And......... A] Contrast & color sense B] light & color sense Ans : B] light & color sense 8. The..... ..... is used almost universally in testing the acuity of vision A] Snellens chart B] Keller acuity chart Ans : A] Snellens chart REFRACTION DEPARTMENT-CBE

94 9.The chart consists of Snellens......... Specially formed letters of the alphabet arranged in rows of decreasing letter size A] Optotypes B] cryotypes Ans : A] Optotypes 10. The Chart consists of a series of letters of diminishing size...... .... A] Letters B] pictures Ans : A] Letters 11. Each Letter is of such a shape that it can be enclosed in a............... A] Square B] perpendicular Ans : A] Square 12. The size of the square is ........ Times the thickness of lines composing the letter A] Four B] five Ans : B] five 13. The Square subtends an angle of......... Minutes at a specified distance A] Four B] five Ans : B] five 14. The Snellens charts should be test at a distance of.....………..

95 A] 4m or 16 feet B] 6m or 20 feet Ans : B] 6m or 20 feet 15. The rays of light from that distance are parallel for ....... Purposes A] Theoretical B] practical Ans : B] practical 16. This test could be carried out in a room with a length of .......... And a breath of minimum ....... Meters A] 3m, 1 1/2 m B] 6m, 2 m Ans : A] 3m, 1 1/2 m 17. The general illumination of the room should not be less than ......... the illumination of the chart A] Two – sixth B] one –fifth Ans : B] one –fifth 18. The chart could be placed above the patients............ A] Face B] head Ans : B] head 19. The patients look at a ...... Hung on the opposite wall A] Chart B] mirror REFRACTION DEPARTMENT-CBE

96 20. First letter is at ............ Distance Ans : B] mirror Ans : A] 60meters A] 60meters B] 6 meters 21. Second line is at .... ...... Distance A] 36m B] 24m 22. Third line is at ........... Distance Ans : A] 36m Ans : B] 24m A] 36m B] 24m Ans : A] 18m Ans : A] 12m 23. Fourth line is at .......... Distance A] 18m B] 9m 24. Fifth line is at .......... Distance A] 12m B] 9m

97 25. Sixth line is at ... ...... Distance A] 9m B] 9cm 26. Seventh line is at ...... ..... Distance Ans : A] 9m Ans : A] 6m A] 6m B] 9m 27. Eighth line is at ........... Distance A] 36m B] 5m Ans : B] 5m 29. Distant Visual acuity chart in adults ......... A] Landolt broken ring chart B] Snellens chart Ans : B] Snellens chart 30. Distant visual acuity checked in illiterates patient by…......... A] E- chart B] log mark chart Ans : A] E- chart 31. In 6 month babiesvision is tested by …… A] Cake decoration B] ETDRS Ans : A] Cake decoration REFRACTION DEPARTMENT-CBE

98 32.Trial set consists of......... A] Trial frame B] E- chart Ans : A] Trial frame 33.Visual acuity is recorded as a ……… A] value B] fraction Ans : B] fraction 34. Patients who wear glasses or contact lenses may be tested with and without ......Correction A] Physical B] optical Ans : B] optical 35. Test and record the vision in each eye separately, beginning with the ……... Eye A] Left B] right Ans : B] right 36. Along with these two tests be also contains picture test type or ........ Can be successfully used in small children aged 4-6years A] new York light house B] Jorgen hand test Ans : B] Jorgen hand test 37. For Preschool children vision test is done by ... .... Test A] Cardiff card B] Allen picture card Ans : B] Allen picture card

99 38. ...... .... Test was previously done in children with low vision or amblyopia A] Becle Collins picture B] new york light house Ans : B] new york light house 39.There are only.... ....... Symbols in flash card A] 2 B] 3 Ans : A] 2 40. ..... .. Test was previously used for handicapped people with low vision A] Cake decoration B] miniature toy test Ans : B] miniature toy test 41. Allen used ... .... Sets of miniature objects A] 3 B] 2 Ans : B] 2 42. ....... Ivory balls of ...... Inch to one and half inch diameter sizes are rolled and Spinned to a distance of 20 feet[a] A] 5, 1/2 B] 7, 1 Ans : A] 5, 1/2 43. Small colored sweet balls of ... ....... Diameter are used to decorate cakes A] 1mm B] 0.1mm REFRACTION DEPARTMENT-CBE

100 Ans : A] 1mm 44. ..... Old children can pick up small objects and eat A] 6 month old B] 12 month old Ans : A] 6 month old 45.The test is repeated with only... .... Sweet sugar balls after covering either eye alternatively A] 2-3 B] 1-2 Ans : B] 1-2 46. Ability to see the sweet indicates the vision of ..... At the testing A] 6/36 B] 6/24 Ans : B] 6/24 47. Principle of keelar acuity test .......... A] Matching test B] preferential looking Ans : B] preferential looking 48. The .....sits comfortably on the mothers lap A] Child B] cake Ans : A] Child 49. The child is shown a coarse grating card at ....... Cm A] 48cm B] 38 cm