ABO Ocular Anatomy & Physiology

Question 1

Which structure of the eye is primarily responsible for focusing light at different distances?

Accepted Answer

Crystalline lens

Answer

The crystalline lens changes shape through accommodation to focus light from objects at varying distances onto the retina.

Question 2

What is the function of the ciliary body?

Accepted Answer

To produce aqueous humor and control lens accommodation

Answer

The ciliary body has two main functions: it produces aqueous humor and contains the ciliary muscle that controls accommodation by changing the shape of the lens.

Question 3

Which layer of the cornea is primarily responsible for maintaining corneal transparency through its pump function?

Accepted Answer

Endothelium

Answer

The corneal endothelium maintains transparency by actively pumping water out of the stroma, preventing corneal edema and clouding.

Question 4

Where are the cone photoreceptors most densely concentrated?

Accepted Answer

Fovea

Answer

The fovea contains the highest concentration of cone photoreceptors and is responsible for sharp central vision and color perception.

Question 5

What is the approximate refractive power of the human cornea?

Accepted Answer

43 diopters

Answer

The cornea contributes approximately 43 diopters (about two-thirds) of the eye's total refractive power of approximately 60 diopters.

ABO - American Board of Optometry Practice Test

ABO - American Board of Optometry Practice Test

ABO Ocular Anatomy & Physiology