Explore a comprehensive set of 40 multiple-choice questions (MCQs) covering the Principles of Refraction and Visual Acuity, tailored for paramedical and allied health exams. This resource delves into topics like emmetropia, myopia, hypermetropia, Snellen chart usage, and accommodation, providing detailed explanations to enhance understanding and exam preparation. Ideal for students and professionals in optometry, ophthalmic sciences, and vision care fields. optometry and ophthalmology mcq
01. The image of an emmetropic eye is formed:
A. On the retina
B. In front of retina
C. Behind retina
D. On cornea
View Answer
A. On the retina ✅ Exp: In emmetropia, parallel rays focus exactly on the retinal plane.
02. Visual acuity mainly depends on:
A. Retinal illumination
B. Pupil size
C. Cone function
D. Rod function
View Answer
C. Cone function ✅ Exp: Central vision (fovea) relies on cone photoreceptors.
03. The unit of visual angle is:
A. Minute of arc
B. Degree
C. Radian
D. Diopter
View Answer
A. Minute of arc ✅ Exp: Smallest resolvable detail is expressed in minutes of arc.
04. Snellen’s chart is used to measure:
A. Field of vision
B. Visual acuity
C. Binocular vision
D. Color vision
View Answer
B. Visual acuity ✅ Exp: It tests distance visual acuity using letters at standard distance.
05. The standard distance for Snellen chart in India:
A. 3 m
B. 4 m
C. 6 m
D. 10 m
View Answer
C. 6 m ✅ Exp: At 6 m, light rays are nearly parallel, minimizing accommodation.
06. Normal visual acuity (6/6) means the patient can read:
A. Letters subtending 1 degree
B. Letters subtending 5 minutes of arc
C. 1 minute of arc
D. 10 minutes of arc
View Answer
B. Letters subtending 5 minutes of arc ✅ Exp: Each letter subtends 5 minutes at 6 m; critical detail = 1 minute.
07. The smallest optotype a normal eye can resolve has lines separated by:
A. 5 minutes
B. 1 minute
C. 10 minutes
D. 2 minutes
View Answer
B. 1 minute ✅ Exp: Minimum separable angle ≈ 1 minute of arc.
08. The denominator in Snellen fraction indicates:
A. Distance of patient from chart
B. Distance at which normal eye can read the line
C. Chart size
D. Refractive error
View Answer
B. Distance at which normal eye can read the line ✅ Exp: 6/12 means letters visible to normal eye at 12 m.
09. Pinhole test improves vision in:
A. Amblyopia
B. Refractive error
C. Cataract
D. Macular disease
View Answer
B. Refractive error ✅ Exp: Pinhole blocks peripheral rays, reducing blur circle.
10. If pinhole does not improve vision, defect =
A. Refractive error
B. Pathological lesion
C. Accommodative spasm
D. Lens error
View Answer
B. Pathological lesion ✅ Exp: No improvement → retinal or optic-nerve pathology.
11. The refractive power of eye is about:
A. 40 D
B. 50 D
C. 60 D
D. 70 D
View Answer
C. 60 D ✅ Exp: Total optical power ≈ +60 diopters (cornea + lens).
12. Cornea contributes about:
A. 20 D
B. 30 D
C. 40 D
D. 50 D
View Answer
C. 40 D ✅ Exp: Cornea ≈ two-thirds of total refractive power.
13. Lens contributes:
A. 10 D
B. 15 D
C. 20 D
D. 30 D
View Answer
C. 20 D ✅ Exp: Lens ≈ +15 to +20 D; adjustable by accommodation.
14. Diopter is the reciprocal of focal length in:
A. Centimeters
B. Meters
C. Millimeters
D. Feet
View Answer
B. Meters ✅ Exp: D = 1/f (in meters).
16. An eye with total power +60 D and axial length 24 mm is:
A. Emmetropic
B. Myopic
C. Hypermetropic
D. Astigmatic
View Answer
A. Emmetropic ✅ Exp: Normal optical power and axial length = emmetropia.
17. One mm change in axial length changes refraction by about:
A. 1 D
B. 2 D
C. 3 D
D. 5 D
View Answer
C. 3 D ✅ Exp: 1 mm = ≈3 D refractive shift.
18. Hypermetropia occurs when:
A. Axial length > 24 mm
B. Axial length < 24 mm
C. Power > 60 D
D. Cornea too steep
View Answer
B. Axial length < 24 mm ✅ Exp: Shorter eye or less power → focus behind retina.
19. Myopia occurs when:
A. Eyeball shorter
B. Eyeball longer
C. Cornea flatter
D. Lens weaker
View Answer
B. Eyeball longer ✅ Exp: Longer axial length → focus in front of retina.
19. Index myopia results from:
A. Lens sclerosis
B. Axial elongation
C. Corneal steepness
D. Accommodation
View Answer
A. Lens sclerosis ✅ Exp: Lens refractive index increases in nuclear sclerosis.
20. Curvature myopia is due to:
A. Steeper cornea
B. Flatter cornea
C. Short eye
D. Low lens power
View Answer
A. Steeper cornea ✅ Exp: Excess curvature increases optical power.
21. Visual acuity depends mainly on:
A. Pupil size and illumination
B. Retinal and neural factors
C. Iris pigmentation
D. Tear film
View Answer
B. Retinal and neural factors ✅ Exp: Macular cones and visual pathway integrity decide acuity.
22. Testing distance for near vision in Jaeger chart:
A. 25 cm
B. 30 cm
C. 33 cm
D. 40 cm
View Answer
A. 25 cm ✅ Exp: Standard near distance = 25 cm.
22. Near point of accommodation in young adult:
A. 5 cm
B. 10 cm
C. 25 cm
D. 50 cm
View Answer
C. 25 cm ✅ Exp: Average amplitude ≈ 4 D → 25 cm.
24. Presbyopia is due to:
A. Short eye
B. Lens sclerosis & loss of elasticity
C. Retinal changes
D. Corneal flattening
View Answer
B. Lens sclerosis & loss of elasticity ✅ Exp: Age-related decline in lens flexibility.
25. Average onset of presbyopia in emmetropes:
A. 30 y
B. 40 y
C. 50 y
D. 60 y
View Answer
B. 40 y ✅ Exp: Accommodation amplitude declines by 40 years.
26. Presbyopia appears earlier in:
A. Myopes
B. Hypermetropes
C. Emmetropes
D. Aphakes
View Answer
B. Hypermetropes ✅ Exp: Hypermetropes already use accommodation.
28. Pseudomyopia is due to:
A. Lens sclerosis
B. Ciliary spasm
C. Corneal edema
D. Index change
View Answer
B. Ciliary spasm ✅ Exp: Excess accommodation mimics myopia.
28. Absolute hypermetropia is:
A. Corrected by accommodation
B. Cannot be corrected by accommodation
C. Hidden error
D. Physiological error
View Answer
B. Cannot be corrected by accommodation ✅ Exp: Portion beyond accommodative ability.
29. Manifest hypermetropia =
A. Latent + Absolute
B. Facultative + Absolute
C. Latent + Facultative
D. None
View Answer
B. Facultative + Absolute ✅ Exp: Manifest part visible on routine refraction.
30. Cycloplegic refraction reveals:
A. Latent hypermetropia
B. Myopia
C. Astigmatism
D. Presbyopia
View Answer
A. Latent hypermetropia ✅ Exp: Paralysis of accommodation exposes hidden + error.
31. Accommodation amplitude in 10-year-old ≈
A. 5 D
B. 10 D
C. 14 D
D. 20 D
View Answer
B. 10 D ✅ Exp: Amplitude decreases with age.
33. Far point of an emmetropic eye is at:
A. 1 m
B. 6 m
C. Infinity
D. 25 cm
View Answer
C. Infinity ✅ Exp: Parallel rays focus on retina at infinity.
33. Near point of accommodation for +4 D amplitude:
A. 25 cm
B. 20 cm
C. 33 cm
D. 50 cm
View Answer
A. 25 cm ✅ Exp: 1/4 = 0.25 m.
34. In hypermetropia, far point lies:
A. Infinity
B. In front of eye
C. Behind eye
D. On retina
View Answer
C. Behind eye ✅ Exp: Focus beyond retinal plane.
35. In myopia, far point lies:
A. Behind eye
B. At infinity
C. In front of eye
D. On retina
View Answer
C. In front of eye ✅ Exp: Rays focus before retina.
36. Diopters required to correct –2 D myope:
A. +2 D
B. –2 D
C. +1 D
D. –1 D
View Answer
B. –2 D ✅ Exp: Use concave lens of equal but opposite power.
37. Hypermetropia corrected by:
A. Concave lens
B. Convex lens
C. Cylindrical lens
D. Prism
View Answer
B. Convex lens ✅ Exp: Plus lens converges rays to retina.
38. Spherical lens with same power in all meridians corrects:
A. Astigmatism
B. Simple myopia or hypermetropia
C. Mixed astigmatism
D. Aphakia
View Answer
B. Simple myopia or hypermetropia ✅ Exp: Equal curvature in all meridians.
39. Cylindrical lenses correct:
A. Myopia
B. Hypermetropia
C. Astigmatism
D. Presbyopia
View Answer
C. Astigmatism ✅ Exp: Neutralize error in one meridian.
40. Visual acuity notation 6/18 means:
A. Poorer than normal by 3 times
B. Better than normal
C. Normal
D. Uncorrectable
View Answer
A. Poorer than normal by 3 times ✅ Exp: Needs letters 3× larger than normal at 6 m.
