Certified Ophthalmic Technician (COT) Practice Test 2026 - Free COT Practice Questions and Study Guide

The benefit of immersion A-scan over contact A-scan primarily lies in its ability to avoid corneal contact during the measurement process. This feature is significant because it reduces the risk of corneal abrasion or irritation that may occur with contact A-scan methods. Additionally, since immersion A-scan utilizes a fluid medium, it can provide more accurate measurements by eliminating the air-to-tissue interface that can distort sound waves. This improved accuracy is particularly beneficial in assessing axial length, which is critical for calculating intraocular lens power for cataract surgery.

While considerations such as cost, required skill levels, and imaging capabilities might be relevant in choosing diagnostic methods, the avoidance of corneal contact directly contributes to patient comfort and safety, making it a notable advantage of immersion A-scan techniques.