ABO Ocular Anatomy & Physiology 2

Question 1

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

Accepted Answer

Corneal endothelium

Answer

The corneal endothelium uses Na+/K+-ATPase pumps to actively remove fluid from the stroma, maintaining corneal clarity.

Question 2

The fovea centralis has the highest visual acuity because it contains predominantly which cell type?

Accepted Answer

Cone photoreceptors

Answer

The fovea centralis is packed with cone photoreceptors and lacks rods, enabling maximum visual acuity and color discrimination.

Question 3

Which structure forms the boundary between the anterior and posterior chambers of the eye?

Accepted Answer

Iris

Answer

The iris separates the anterior chamber (between cornea and iris) from the posterior chamber (between iris and lens).

Question 4

The optic nerve head receives its blood supply primarily from which arterial source?

Accepted Answer

Short posterior ciliary arteries

Answer

The prelaminar and laminar portions of the optic nerve head are supplied mainly by branches of the short posterior ciliary arteries.

Question 5

What is the primary function of the ciliary body's pars plana?

Accepted Answer

Vitreous attachment point and surgical access site

Answer

The pars plana is a relatively avascular, flat region that serves as a safe surgical access site and anchors the vitreous base.

ABO - American Board of Optometry Practice Test