COA Ocular Anatomy and Physiology

Question 1

The avascular cornea receives oxygen primarily from which sources?

Accepted Answer

Tear film and aqueous humor

Answer

The cornea gets oxygen anteriorly from the tear film and posteriorly from the aqueous humor due to its avascularity.

Question 2

Which layer of the cornea has the greatest capacity for regeneration after injury?

Accepted Answer

Epithelium

Answer

The corneal epithelium regenerates completely within 24–72 hours because of its rapid mitotic activity.

Question 3

Aqueous humor is produced by which ocular structure?

Accepted Answer

Ciliary body

Answer

The ciliary body produces aqueous humor through active secretion and passive ultrafiltration from ciliary processes.

Question 4

The macula lutea is characterized by which feature?

Accepted Answer

High concentration of cones and the fovea centralis

Answer

The macula contains the highest cone density and the fovea centralis, providing the sharpest central vision.

Question 5

The physiologic blind spot corresponds to which ocular structure?

Accepted Answer

The optic disc where no photoreceptors exist

Answer

The optic disc contains no photoreceptors because retinal nerve fibers exit here, creating a scotoma about 15 degrees temporal to fixation.

COA - Certified Ophthalmic Assistant Practice Test