OAT (Optometry Admission Test) EXAM TEST
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES -2026 |NSTANT
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1. Which part of the eye is responsible for controlling the
amount of light entering the eye?
A. Cornea
B. Iris
C. Lens
D. Retina
Answer: B. Iris
Rationale: The iris regulates the size of the pupil, controlling
light entry into the eye.
2. What is the primary function of the macula in the retina?
A. Peripheral vision
B. Color vision and sharp central vision
C. Depth perception
D. Night vision
Answer: B. Color vision and sharp central vision
Rationale: The macula contains a high density of cone
photoreceptors responsible for central, high-resolution, color
vision.
3. Which condition is characterized by clouding of the lens?
A. Glaucoma
B. Cataract
,C. Myopia
D. Astigmatism
Answer: B. Cataract
Rationale: A cataract is the opacification of the lens, leading to
blurred vision.
4. Which ocular structure produces aqueous humor?
A. Ciliary body
B. Iris
C. Retina
D. Lens
Answer: A. Ciliary body
Rationale: The ciliary processes in the ciliary body secrete
aqueous humor, which nourishes the cornea and lens.
5. Which cranial nerve controls most of the eye’s extraocular
muscles?
A. Optic nerve (CN II)
B. Oculomotor nerve (CN III)
C. Trochlear nerve (CN IV)
D. Abducens nerve (CN VI)
Answer: B. Oculomotor nerve (CN III)
Rationale: CN III innervates the superior, inferior, and medial
rectus muscles, inferior oblique, and levator palpebrae
superioris.
6. Which condition is associated with increased intraocular
pressure leading to optic nerve damage?
A. Cataract
,B. Glaucoma
C. Macular degeneration
D. Retinitis pigmentosa
Answer: B. Glaucoma
Rationale: Glaucoma is characterized by elevated intraocular
pressure causing optic neuropathy.
7. Which refractive error is caused by an elongated eyeball?
A. Myopia
B. Hyperopia
C. Presbyopia
D. Astigmatism
Answer: A. Myopia
Rationale: Myopia (nearsightedness) occurs when the eye is too
long, causing light to focus in front of the retina.
8. Which refractive error is due to aging and loss of lens
elasticity?
A. Myopia
B. Hyperopia
C. Presbyopia
D. Astigmatism
Answer: C. Presbyopia
Rationale: Presbyopia is age-related farsightedness due to
decreased lens accommodation.
9. Which structure of the eye has the highest concentration of
cone photoreceptors?
A. Fovea
, B. Peripheral retina
C. Optic disc
D. Ciliary body
Answer: A. Fovea
Rationale: The fovea, located in the center of the macula, is
densely packed with cones for high-acuity vision.
10. Which part of the eye is transparent and contributes most
to the eye’s focusing power?
A. Lens
B. Cornea
C. Vitreous humor
D. Iris
Answer: B. Cornea
Rationale: The cornea provides ~70% of the eye’s refractive
power and is transparent to light.
11. Which type of photoreceptor is responsible for vision in
dim light?
A. Cones
B. Rods
C. Bipolar cells
D. Ganglion cells
Answer: B. Rods
Rationale: Rods are highly sensitive to low light and mediate
scotopic (night) vision.
12. Which layer of the retina contains photoreceptors?
A. Ganglion cell layer
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES -2026 |NSTANT
DOWNLOAD PDF
1. Which part of the eye is responsible for controlling the
amount of light entering the eye?
A. Cornea
B. Iris
C. Lens
D. Retina
Answer: B. Iris
Rationale: The iris regulates the size of the pupil, controlling
light entry into the eye.
2. What is the primary function of the macula in the retina?
A. Peripheral vision
B. Color vision and sharp central vision
C. Depth perception
D. Night vision
Answer: B. Color vision and sharp central vision
Rationale: The macula contains a high density of cone
photoreceptors responsible for central, high-resolution, color
vision.
3. Which condition is characterized by clouding of the lens?
A. Glaucoma
B. Cataract
,C. Myopia
D. Astigmatism
Answer: B. Cataract
Rationale: A cataract is the opacification of the lens, leading to
blurred vision.
4. Which ocular structure produces aqueous humor?
A. Ciliary body
B. Iris
C. Retina
D. Lens
Answer: A. Ciliary body
Rationale: The ciliary processes in the ciliary body secrete
aqueous humor, which nourishes the cornea and lens.
5. Which cranial nerve controls most of the eye’s extraocular
muscles?
A. Optic nerve (CN II)
B. Oculomotor nerve (CN III)
C. Trochlear nerve (CN IV)
D. Abducens nerve (CN VI)
Answer: B. Oculomotor nerve (CN III)
Rationale: CN III innervates the superior, inferior, and medial
rectus muscles, inferior oblique, and levator palpebrae
superioris.
6. Which condition is associated with increased intraocular
pressure leading to optic nerve damage?
A. Cataract
,B. Glaucoma
C. Macular degeneration
D. Retinitis pigmentosa
Answer: B. Glaucoma
Rationale: Glaucoma is characterized by elevated intraocular
pressure causing optic neuropathy.
7. Which refractive error is caused by an elongated eyeball?
A. Myopia
B. Hyperopia
C. Presbyopia
D. Astigmatism
Answer: A. Myopia
Rationale: Myopia (nearsightedness) occurs when the eye is too
long, causing light to focus in front of the retina.
8. Which refractive error is due to aging and loss of lens
elasticity?
A. Myopia
B. Hyperopia
C. Presbyopia
D. Astigmatism
Answer: C. Presbyopia
Rationale: Presbyopia is age-related farsightedness due to
decreased lens accommodation.
9. Which structure of the eye has the highest concentration of
cone photoreceptors?
A. Fovea
, B. Peripheral retina
C. Optic disc
D. Ciliary body
Answer: A. Fovea
Rationale: The fovea, located in the center of the macula, is
densely packed with cones for high-acuity vision.
10. Which part of the eye is transparent and contributes most
to the eye’s focusing power?
A. Lens
B. Cornea
C. Vitreous humor
D. Iris
Answer: B. Cornea
Rationale: The cornea provides ~70% of the eye’s refractive
power and is transparent to light.
11. Which type of photoreceptor is responsible for vision in
dim light?
A. Cones
B. Rods
C. Bipolar cells
D. Ganglion cells
Answer: B. Rods
Rationale: Rods are highly sensitive to low light and mediate
scotopic (night) vision.
12. Which layer of the retina contains photoreceptors?
A. Ganglion cell layer
