Master retinal physiology of 80 retina and phototransduction mcq, covering rods, cones, ERG, visual pathways & clinical correlations test your knowledge now visit our index page to find topic wise ophthalmology mcq
Retinal Function & Vision
41. Rods are specialized for:
A. Color vision
B. High acuity vision
C. Night vision
D. Central vision
View Answer
C. Night vision ✅ Exp: Rods = scotopic (dim light) vision, peripheral.
42. Cones are concentrated in:
A. Peripheral retina
B. Optic disc
C. Fovea
D. Ora serrata
View Answer
C. Fovea ✅ Exp: Fovea contains only cones → sharp vision.
43. The blind spot corresponds to:
A. Fovea
B. Optic disc
C. Ora serrata
D. Retinal periphery
View Answer
B. Optic disc ✅ Exp: No photoreceptors at optic disc.
44. The Purkinje shift refers to:
A. Shift from cone to rod vision in dim light
B. Shift from rod to cone vision
C. Color blindness
D. Visual field shift
View Answer
A. Shift from cone to rod vision in dim light ✅ Exp: Peak sensitivity shifts from cones (~555 nm) to rods (~507 nm) at low light.
45. Critical flicker fusion frequency (CFFF) is highest in:
A. Fovea
B. Peripheral retina
C. Optic disc
D. Retinal periphery only
View Answer
A. Fovea ✅ Exp: Cones at fovea detect flicker at high frequency.
46. The Stiles-Crawford effect describes:
A. Directional sensitivity of cones
B. Rod degeneration in RP
C. Blue-yellow color blindness
D. Retinal after-images
View Answer
A. Directional sensitivity of cones ✅ Exp: Light entering along cone axis is more effective.
47. The minimum angle of resolution (MAR) for normal vision:
A. 5 arc min
B. 2 arc min
C. 1 arc min
D. 10 arc min
View Answer
C. 1 arc min ✅ Exp: Visual acuity = ability to resolve 1 arc minute detail.
48. Contrast sensitivity is best measured at:
A. Low spatial frequencies
B. Intermediate spatial frequencies
C. High spatial frequencies
D. Blind spot
View Answer
B. Intermediate spatial frequencies ✅ Exp: Maximal sensitivity at mid-range frequencies.
49. Photopic vision is mediated by:
A. Rods
B. Cones
C. Both rods & cones
D. Ganglion cells
View Answer
B. Cones ✅ Exp: Cones mediate day & color vision.
50. Scotopic vision is mediated by:
A. Rods
B. Cones
C. Ganglion cells
D. Amacrine cells
View Answer
A. Rods ✅ Exp: Rods mediate dim-light vision.
Electrophysiology
51. In electroretinogram (ERG), a-wave originates from:
A. Photoreceptors
B. Bipolar cells
C. Ganglion cells
D. Muller cells
View Answer
A. Photoreceptors ✅ Exp: a-wave = rods/cones response.
52. b-wave of ERG is generated mainly by:
A. Muller + bipolar cells
B. Ganglion cells
C. Amacrine cells
D. RPE
View Answer
A. Muller + bipolar cells ✅ Exp: Represents ON-bipolar activity.
53. c-wave of ERG represents:
A. Photoreceptors
B. RPE
C. Ganglion cells
D. Muller cells
View Answer
B. RPE ✅ Exp: c-wave arises from RPE.
54. Electro-oculogram (EOG) light peak to dark trough ratio is called:
A. Arden ratio
B. ERG ratio
C. Scotopic ratio
D. Photopic ratio
View Answer
A. Arden ratio ✅ Exp: Normal Arden ratio > 1.8.
55. Visual evoked potential (VEP) assesses function of:
A. Retina
B. Optic nerve & visual cortex
C. RPE
D. Muller cells
View Answer
B. Optic nerve & visual cortex ✅ Exp: VEP tests visual pathway beyond retina.
56. Pattern VEP is most useful in:
A. Amblyopia
B. Retinitis pigmentosa
C. Cataract
D. Vitreous hemorrhage
View Answer
A. Amblyopia ✅ Exp: Detects functional vision in amblyopia.
57. ERG is extinguished in:
A. Retinitis pigmentosa
B. Optic neuritis
C. Macular degeneration
D. Papilledema
View Answer
A. Retinitis pigmentosa ✅ Exp: RP → progressive rod-cone degeneration.
58. ERG is normal but VEP is abnormal in:
A. Optic neuritis
B. RP
C. CRAO
D. Macular degeneration
View Answer
A. Optic neuritis ✅ Exp: Optic nerve disease → VEP abnormal, ERG normal.
59. EOG is abnormal in:
A. Best’s vitelliform dystrophy
B. Optic neuritis
C. Papilledema
D. Retinitis pigmentosa
View Answer
A. Best’s vitelliform dystrophy ✅ Exp: Classic feature of Best’s disease.
60. Multifocal ERG is used to evaluate:
A. Localized retinal function
B. Optic nerve
C. Visual cortex
D. Choroidal blood flow
View Answer
A. Localized retinal function ✅ Exp: Tests multiple retinal loci simultaneously.
61. Central serous chorioretinopathy (CSCR) involves:
A. Detachment of neurosensory retina
B. Detachment of RPE
C. Retinal tear
D. Vitreous hemorrhage
View Answer
A. Detachment of neurosensory retina ✅ Exp: Fluid leaks under retina from choroid.
62. Retinoblastoma arises from:
A. RPE
B. Retinal neuroblasts
C. Ganglion cells
D. Muller cells
View Answer
B. Retinal neuroblasts ✅ Exp: Malignant tumor of primitive retinal cells.
63. Cherry red spot is seen in:
A. CRAO
B. RP
C. CSCR
D. Macular hole
View Answer
A. CRAO ✅ Exp: Fovea spared as surrounding retina opaque.
64. Retinitis pigmentosa typically starts with:
A. Night blindness
B. Photophobia
C. Central vision loss
D. Diplopia
View Answer
A. Night blindness ✅ Exp: Rods affected first → nyctalopia.
65. Stargardt’s disease is a:
A. Juvenile macular dystrophy
B. Retinal detachment
C. Rod-cone dystrophy
D. Glaucoma
View Answer
A. Juvenile macular dystrophy ✅ Exp: Inherited macular degeneration in children.
66. Leber’s congenital amaurosis presents as:
A. Severe blindness in infancy
B. Adult-onset RP
C. Optic neuritis
D. Amblyopia
View Answer
A. Severe blindness in infancy ✅ Exp: Early-onset hereditary retinal dystrophy.
67. Cone dystrophies present as:
A. Night blindness
B. Loss of color & central vision
C. Peripheral field loss
D. Total blindness at birth
View Answer
B. Loss of color & central vision ✅ Exp: Cones primarily affected → central loss.
68. Oguchi’s disease is a:
A. Form of stationary night blindness
B. Optic neuropathy
C. RPE disorder
D. Cone dystrophy
View Answer
A. Form of stationary night blindness ✅ Exp: Rare rod dysfunction, improved vision after dark adaptation.
69. Fundus albipunctatus shows:
A. Multiple white dots in retina
B. Cherry red spot
C. Bone spicules
D. Hemorrhages
View Answer
A. Multiple white dots in retina ✅ Exp: Stationary night blindness with white dots.
70. Albinism causes defective vision due to:
A. Lack of melanin in RPE
B. Optic nerve hypoplasia
C. Lens opacity
D. Absent Muller cells
View Answer
A. Lack of melanin in RPE ✅ Exp: Poor foveal development + abnormal chiasmal crossing.
.71. Bitemporal hemianopia is due to:
A. Optic nerve lesion
B. Chiasmal lesion
C. Optic tract lesion
D. Occipital lobe lesion
View Answer
B. Chiasmal lesion ✅ Exp: Chiasmal compression (pituitary adenoma).
72. Homonymous hemianopia is caused by:
A. Chiasmal lesion
B. Optic tract or occipital lesion
C. Optic nerve lesion
D. Retinal detachment
View Answer
B. Optic tract or occipital lesion ✅ Exp: Post-chiasmal lesion → same side field loss.
73. Central scotoma is typical of:
A. Optic neuritis
B. Glaucoma
C. RP
D. Retinal detachment
View Answer
A. Optic neuritis ✅ Exp: Demyelination damages central fibers.
74. Arcuate scotoma is seen in:
A. Glaucoma
B. Optic neuritis
C. CSCR
D. CRAO
View Answer
A. Glaucoma ✅ Exp: Damage to retinal nerve fiber layer.
75. Altitudinal visual field defect suggests:
A. Ischemic optic neuropathy
B. RP
C. Glaucoma
D. CSCR
View Answer
A. Ischemic optic neuropathy ✅ Exp: Infarction of optic nerve head circulation.
76. Quadrantanopia occurs with:
A. Optic chiasm
B. Temporal or parietal lobe lesion
C. Optic nerve
D. Fovea
View Answer
B. Temporal or parietal lobe lesion ✅ Exp: Meyer’s loop = superior quadrantanopia; parietal = inferior.
77. Macular sparing hemianopia occurs in:
A. Optic nerve disease
B. Occipital lobe infarct
C. RP
D. Glaucoma
View Answer
B. Occipital lobe infarct ✅ Exp: Due to dual blood supply of occipital pole.
78. Which retinal cells are most radiosensitive?
A. Photoreceptors
B. Ganglion cells
C. Muller cells
D. RPE
View Answer
A. Photoreceptors ✅ Exp: Photoreceptors highly sensitive to radiation.
79. Retinal ischemia first affects:
A. Inner retina
B. Outer retina
C. RPE
D. Muller cells
View Answer
A. Inner retina ✅ Exp: Inner retina depends on central retinal artery → ischemia first.
80. The layer of retina most resistant to ischemia is:
A. Photoreceptors
B. Outer retina (supplied by choroid)
C. Inner retina
D. Ganglion cells
View Answer
B. Outer retina (supplied by choroid) ✅ Exp: Choroidal supply is rich & resistant to ischemia.
