ABO Ocular Anatomy & Physiology 5

Question 1

The lacrimal gland produces the aqueous component of the tear film. Its secretory activity is stimulated primarily by:

Accepted Answer

Parasympathetic fibers from the facial nerve (CN VII)

Answer

Parasympathetic fibers traveling with the facial nerve (CN VII) via the pterygopalatine ganglion stimulate lacrimal gland secretion.

Question 2

The retinal blood supply from the central retinal artery nourishes which retinal layers?

Accepted Answer

The inner two-thirds of the retina (inner nuclear layer and inward)

Answer

The central retinal artery supplies the inner two-thirds of the retina (from the nerve fiber layer to the inner nuclear layer), while the outer retina is supplied by the choroid.

Question 3

Which muscle is the sole abductor of the eye, innervated exclusively by CN VI?

Accepted Answer

Lateral rectus

Answer

The lateral rectus is the only extraocular muscle innervated by the abducens nerve (CN VI) and is the primary abductor of the eye.

Question 4

What is the approximate normal central corneal thickness in adults?

Accepted Answer

520-560 microns

Answer

Normal central corneal thickness averages approximately 520-560 microns (about 0.5 mm), which is clinically important for IOP measurement correction.

Question 5

The scleral spur is a ridge of dense connective tissue that serves as the attachment point for which structure?

Accepted Answer

The ciliary muscle and the posterior portion of the trabecular meshwork

Answer

The scleral spur anchors the ciliary muscle and the posterior trabecular meshwork, and its position is a key gonioscopic landmark.

ABO - American Board of Optometry Practice Test

ABO - American Board of Optometry Practice Test

ABO Ocular Anatomy & Physiology 5