Explore Lens and Vitreous Physiology MCQs with answers and explanations from mcq zone ophthalmology. the Physiology of Eye and Vision chapter. Learn important concepts of lens metabolism, transparency, cataract formation, vitreous structure, and ocular physiology. Perfect for optometry students, ophthalmic officers, and government exam aspirants preparing for AIIMS, RRB, ESIC, BSc Optometry, and Ophthalmology entrance exams. Practice now on mcq zone ophthalmology your trusted source for eye anatomy and physiology MCQs. visit out index page to explore topic wise mcq.

1. The lens is avascular and receives nutrition mainly from:
A. Retinal circulation
B. Aqueous humor
C. Vitreous body
D. Corneal epithelium

View Answer

B. Aqueous humor ✅ Exp: Lens derives glucose, oxygen, and metabolites from aqueous humor.

2. Main energy pathway in lens:
A. Aerobic glycolysis
B. Anaerobic glycolysis
C. Oxidative phosphorylation
D. Krebs cycle

View Answer

B. Anaerobic glycolysis ✅ Exp: ~80% of lens ATP is from anaerobic glycolysis due to avascularity.

3. Lens transparency is maintained by:
A. Uniform arrangement of lens fibres
B. High water content
C. Vascular supply
D. Melanin pigment

View Answer

A. Uniform arrangement of lens fibres ✅ Exp: Precise alignment of fibres + lack of organelles ensures clarity.

4. Lens capsule is secreted by:
A. Lens epithelium
B. Corneal epithelium
C. Ciliary body
D. Iris

View Answer

A. Lens epithelium ✅ Exp: Lens epithelium produces capsule throughout life.

5. Lens epithelium is located at:
A. Entire surface
B. Anterior surface only
C. Posterior surface only
D. Equator only

View Answer

B. Anterior surface only ✅ Exp: Only anterior surface has epithelium.

6. Lens growth occurs throughout life by:
A. Addition of new fibres at equator
B. Mitotic activity of posterior epithelium
C. Migration of corneal cells
D. Deposition of collagen

View Answer

A. Addition of new fibres at equator ✅ Exp: New lens fibres added at equatorial region → lens thickens.

7. Presbyopia is caused by:
A. Lens hardening with age
B. Loss of corneal elasticity
C. Increased aqueous pressure
D. Axial elongation

View Answer

A. Lens hardening with age ✅ Exp: Decreased lens elasticity → loss of accommodation.

8. Normal refractive index of lens is approximately:
A. 1.30
B. 1.40
C. 1.50
D. 1.60

View Answer

B. 1.40 ✅ Exp: Mean refractive index ~1.39–1.41.

9. Lens proteins belong mainly to:
A. Globulins
B. Crystallins
C. Albumin
D. Collagen

View Answer

B. Crystallins ✅ Exp: Crystallins (α, β, γ) maintain transparency.

10. Alpha-crystallins function as:
A. Refractive proteins only
B. Molecular chaperones preventing protein aggregation
C. Structural collagen
D. Enzymes

View Answer

B. Molecular chaperones preventing protein aggregation ✅ Exp: α-crystallins prevent aggregation, resist cataract formation.

Lens Metabolism & Clinical

11. Glucose is metabolized in lens mainly via:
A. Glycolysis (anaerobic)
B. Pentose phosphate pathway
C. Krebs cycle
D. Gluconeogenesis

View Answer

A. Glycolysis (anaerobic) ✅ Exp: >80% anaerobic glycolysis.

12. In diabetic lens, excess glucose is converted to:
A. Sorbitol
B. Galactose
C. Fructose
D. Glycerol

View Answer

A. Sorbitol ✅ Exp: Aldose reductase converts glucose → sorbitol → osmotic cataract.

13. Cataract due to sorbitol accumulation is called:
A. Senile cataract
B. Snowflake cataract
C. Traumatic cataract
D. Nuclear cataract

View Answer

B. Snowflake cataract ✅ Exp: Seen in uncontrolled diabetes.

14. Lens glutathione (GSH) acts as:
A. Antioxidant
B. Osmotic regulator
C. Enzyme
D. Protein stabilizer

View Answer

A. Antioxidant ✅ Exp: GSH maintains transparency by preventing oxidative stress.

15. UV light-induced cataract is prevented by:
A. Ascorbate & glutathione
B. Albumin
C. Mydriatics
D. Carotenoids

View Answer

A. Ascorbate & glutathione ✅ Exp: Natural antioxidants protect lens proteins.

16. Lens epithelial Na+/K+ ATPase maintains:
A. Lens transparency & ion balance
B. Corneal curvature
C. Aqueous humor production
D. Retinal circulation

View Answer

A. Lens transparency & ion balance ✅ Exp: Critical for fluid/ion homeostasis.

17. Which vitamin deficiency predisposes to cataract?
A. Vitamin A
B. Vitamin C
C. Riboflavin (B2)
D. Vitamin D

View Answer

C. Riboflavin (B2) ✅ Exp: Riboflavin deficiency → nuclear cataracts.

18. Lens thickness increases with age at a rate of about:
A. 0.01 mm/year
B. 0.1 mm/year
C. 1 mm/year
D. 0.5 mm/year

View Answer

A. 0.01 mm/year ✅ Exp: Adds new fibres continuously.

19. Which lens region has the oldest fibres?
A. Cortex
B. Nucleus
C. Epithelium
D. Equator

View Answer

B. Nucleus ✅ Exp: Central embryonic nucleus contains oldest fibres.

20. Lens accommodates by:
A. Increase in convexity of anterior surface
B. Flattening of anterior surface
C. Posterior shift of cornea
D. Change in aqueous pressure

View Answer

A. Increase in convexity of anterior surface ✅ Exp: Contraction of ciliary muscle → zonular relaxation → lens bulges anteriorly.

Vitreous Physiology

21. Vitreous humor is mainly composed of:
A. Water (98–99%)
B. Protein
C. Lipid
D. Glycogen

View Answer

A. Water (98–99%) ✅ Exp: Nearly all water with small amounts of collagen & hyaluronic acid.

22. Major structural protein of vitreous:
A. Albumin
B. Collagen type II
C. Collagen type IV
D. Fibrinogen

View Answer

B. Collagen type II ✅ Exp: Type II collagen gives framework.

23. Main glycosaminoglycan in vitreous:
A. Heparin
B. Hyaluronic acid
C. Dermatan sulfate
D. Chondroitin sulfate

View Answer

B. Hyaluronic acid ✅ Exp: Maintains gel consistency.

24. Vitreous is attached most strongly at:
A. Vitreous base (ora serrata)
B. Posterior pole
C. Optic disc margin
D. Retinal vessels

View Answer

A. Vitreous base (ora serrata) ✅ Exp: Vitreous base = firmest adhesion.

25. Physiological role of vitreous:
A. Shock absorber
B. Refracting medium
C. Protein source
D. Pigment filter

View Answer

A. Shock absorber ✅ Exp: Supports retina, protects eye against trauma.

26. Oxygen tension is highest in vitreous near:
A. Retina
B. Lens
C. Vitreous base
D. Retina and ciliary body

View Answer

D. Retina and ciliary body ✅ Exp: Oxygen diffuses from retinal & ciliary circulation.

27. After age 40, vitreous begins to:
A. Liquefy (synchysis)
B. Calcify
C. Vascularize
D. Pigment

View Answer

A. Liquefy (synchysis) ✅ Exp: Liquefaction → posterior vitreous detachment.

28. Posterior vitreous detachment (PVD) is due to:
A. Vitreous liquefaction + weakened vitreoretinal adhesion
B. Increased vitreous pressure
C. Vascular leakage
D. Trauma only

View Answer

A. Vitreous liquefaction + weakened vitreoretinal adhesion ✅ Exp: Natural aging process after 40–50 yrs.

29. The cloquet’s canal represents:
A. Remnant of hyaloid artery
B. Lens capsule
C. Trabecular pathway
D. Choroidal fissure

View Answer

A. Remnant of hyaloid artery ✅ Exp: Central vitreous channel from hyaloid artery.

30. The normal volume of vitreous humor is about:
A. 1 ml
B. 2 ml
C. 4 ml
D. 4 ml (posterior chamber ~4 ml)

View Answer

D. 4 ml (posterior chamber ~4 ml) ✅ Exp: Vitreous ~4 ml, bulk of eye volume.

31. Asteroid hyalosis consists of:
A. Calcium-lipid deposits
B. Cholesterol crystals
C. Hyaluronic acid
D. Collagen fibrils

View Answer

A. Calcium-lipid deposits ✅ Exp: Benign condition with calcium-lipid bodies.

32. Synchysis scintillans is due to:
A. Cholesterol crystals in liquefied vitreous
B. Calcium salts
C. Fibrin clots
D. Hemoglobin breakdown

View Answer

A. Cholesterol crystals in liquefied vitreous ✅ Exp: Seen in chronic uveitis, trauma.

33. Persistent hyperplastic primary vitreous (PHPV) results from:
A. Failure of hyaloid regression
B. Corneal opacities
C. Retinal detachment
D. Glaucoma

View Answer

A. Failure of hyaloid regression ✅ Exp: Hyaloid system fails to regress.

34. Which of the following causes floaters?
A. Vitreous liquefaction
B. High myopia
C. Vitreous hemorrhage
D. All of the above

View Answer

D. All of the above ✅ Exp: Floaters may result from liquefaction, hemorrhage, or myopia.

35. Most common complication of vitreous liquefaction:
A. Retinal detachment
B. Cataract
C. Glaucoma
D. Optic neuritis

View Answer

A. Retinal detachment ✅ Exp: PVD can tear retina → detachment.

36. Proliferative diabetic retinopathy affects vitreous by:
A. Neovascular growth into vitreous
B. Calcification
C. Vitreous atrophy
D. Increased protein content only

View Answer

A. Neovascular growth into vitreous ✅ Exp: Fibrovascular proliferation extends into vitreous.

37. Vitreous hemorrhage often presents with:
A. Sudden floaters & vision loss
B. Pain
C. Photophobia
D. Diplopia

View Answer

A. Sudden floaters & vision loss ✅ Exp: Blood in vitreous blocks vision → floaters.

38. Which enzyme helps maintain vitreous gel state?
A. Hyaluronidase
B. Hyaluronic acid synthase
C. Carbonic anhydrase
D. Aldolase

View Answer

B. Hyaluronic acid synthase ✅ Exp: Synthesizes HA for viscosity.

39. After enucleation, vitreous is replaced in implants by:
A. Silicone oil
B. Albumin
C. Balanced salt solution
D. Collagen

View Answer

A. Silicone oil ✅ Exp: Silicone oil used to maintain retinal attachment.

40. Which condition shows “tobacco dust” in anterior vitreous?
A. Retinal tear
B. Uveitis
C. Cataract
D. Keratitis

View Answer

A. Retinal tear ✅ Exp: Pigment cells (Shaffer’s sign) indicate retinal tear.

41. The refractive power of lens is about:
A. 10 D
B. 15 D
C. 20 D
D. 25 D

View Answer

C. 20 D ✅ Exp: Lens contributes ~20D of total eye power.

42. Lens weight at birth is ~:
A. 65 mg
B. 150 mg
C. 250 mg
D. 500 mg

View Answer

A. 65 mg ✅ Exp: Increases with age (~250 mg by 90 yrs).

43. The main site of lens metabolism:
A. Lens epithelium
B. Lens nucleus
C. Capsule
D. Cortex

View Answer

A. Lens epithelium ✅ Exp: Active metabolism in epithelium.

44. Vitreous transparency is due to:
A. Uniform collagen fibril spacing
B. Pigment
C. Absence of water
D. High proteins

View Answer

A. Uniform collagen fibril spacing ✅ Exp: Lattice arrangement + HA spacing = clear vitreous.

45. The “after-cataract” commonly refers to:
A. Posterior capsular opacification
B. Secondary glaucoma
C. Aphakia
D. Pseudophakia

View Answer

A. Posterior capsular opacification ✅ Exp: Fibrosis or proliferation on posterior capsule.

46. Lens absorbs which UV radiation maximally?
A. 200–280 nm
B. 300–400 nm
C. 400–500 nm
D. >500 nm

View Answer

B. 300–400 nm ✅ Exp: Lens blocks harmful UV-B.

47. Which drug causes posterior subcapsular cataract?
A. Steroids
B. Timolol
C. Pilocarpine
D. Beta-blockers

View Answer

A. Steroids ✅ Exp: Classic steroid side effect.

48. Galactosemia causes:
A. Oil droplet cataract
B. Snowflake cataract
C. Nuclear cataract
D. Posterior polar cataract

View Answer

A. Oil droplet cataract ✅ Exp: Due to accumulation of galactitol.

49. Wilson’s disease lens sign:
A. Sunflower cataract
B. Oil droplet cataract
C. Christmas tree cataract
D. Rosette cataract

View Answer

A. Sunflower cataract ✅ Exp: Copper deposition → sunflower pattern.

50. Christmas tree cataract is seen in:
A. Myotonic dystrophy
B. Diabetes
C. Wilson’s disease
D. Galactosemia

View Answer

A. Myotonic dystrophy ✅ Exp: Multicolored crystals in myotonic dystrophy.