Ocular Anatomy and Physiology Questions and Answers Flashcards
6 cards from real ABO NOCE Basic Opticianry practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Ocular Anatomy and Physiology Questions and Answers flashcards as text
Which layer of the cornea is responsible for maintaining corneal transparency through active fluid pumping?
Answer: Corneal endothelium
The corneal endothelium uses active Na+/K+ ATPase pumps to remove fluid from the stroma, maintaining dehydration and transparency.
The fovea centralis is important in opticianry because:
Answer: It provides the highest visual acuity and is the target for optical center placement
The fovea centralis contains the highest density of cone photoreceptors, providing maximum visual acuity. Optical centers should align with the line of sight to the fovea.
What is the function of the ciliary muscle in accommodation?
Answer: It contracts to release zonular tension, allowing the crystalline lens to become more convex
Ciliary muscle contraction releases tension on the zonules, allowing the elastic crystalline lens to increase curvature (become more convex) for near focus.
The aqueous humor is produced by the:
Answer: Ciliary body (ciliary processes)
The ciliary processes of the ciliary body secrete aqueous humor, which fills the anterior and posterior chambers and maintains intraocular pressure.
Which cranial nerve controls most of the extraocular muscles responsible for eye movement?
Answer: Cranial nerve III (oculomotor)
CN III (oculomotor nerve) innervates the superior rectus, inferior rectus, medial rectus, inferior oblique, and levator palpebrae — controlling most eye movements.
Intraocular pressure (IOP) is measured with which instrument, and what is the normal range?
Answer: Tonometer; normal range is 10–21 mmHg
IOP is measured with a tonometer (applanation or non-contact type). Normal IOP is 10–21 mmHg; elevated IOP is a major glaucoma risk factor.