COT Study Guide 2026

Sclerotic scatter illuminates the cornea via total internal reflection from the limbus, making stromal haze and edema visible as a glow against a dark background.

The Tono-Pen and iCare rebound tonometer are less affected by corneal irregularity and scarring than applanation or air-puff tonometers. They take multiple small-area readings, which are then averaged, providing a more reliable IOP measurement on compromised corneas.

A high refractive error causes the light rays to be far from neutralized, resulting in a retinoscopic reflex that is dim, wide, and slow-moving. As lenses are added and neutrality is approached, the reflex becomes brighter, narrower, and faster. Accommodation would cause the reflex to fluctuate, not necessarily be dim and slow.

Cranial nerve VI, the abducens nerve, innervates the lateral rectus muscle, which is solely responsible for abduction (outward movement) of the eye. Therefore, a lesion of CN VI would result in an inability to abduct the eye on the affected side. CN III innervates most of the other extraocular muscles, and CN IV innervates the superior oblique.

Hand hygiene before and after each patient encounter is the single most effective way to prevent healthcare-associated infections.

The ciliary body epithelium secretes aqueous humor into the posterior chamber, where it flows through the pupil into the anterior chamber.