Certified Ophthalmic Technician (COT) Practice Test 2025 - Free COT Practice Questions and Study Guide

Retroillumination is a technique primarily used to visualize structures within the eye by utilizing a light source behind the structure being examined. This method enhances the contrast of various components in the eye, particularly allowing for a clear view of any opacities or defects present in the iris.

When light is shone through the pupil, any opacities in the iris will block the light and produce shadowing effects, making abnormalities or defects more apparent. This technique is particularly useful in evaluating not only the iris but also other structures like the lens and cornea. However, in this context, the primary emphasis is on identifying iris opacities or irregularities, which is why detecting defects in the iris is the main focus of retroillumination.

While retroillumination can also provide insights into lens opacities and other ocular conditions, the clarity and effectiveness of this method are especially pronounced in evaluating the iris. Thus, the ability of retroillumination to highlight iris defects makes it a valuable tool in clinical practice.