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

The radiuscope is the appropriate instrument for checking lens warpage because it is specifically designed to measure the curvature of optical surfaces, particularly lenses. When a lens warps, the curvature can change, leading to distortions in vision. The radiuscope provides precise measurements of the radius of curvature and allows the technician to detect any irregularities in lens shape. This function is crucial for ensuring that lenses are corrected accurately for vision, particularly in eyewear prescriptions.

In contrast, the slit lamp is mainly used for examining the anterior segment of the eye, such as the cornea and lens, but does not provide the necessary measurements for assessing lens warpage. The tonometer is used to measure intraocular pressure, which is unrelated to lens shape. The retinoscope is used to determine refractive error by observing the way light reflects off the retina and is not designed to assess lens curvature. Therefore, the radiuscope is the only instrument on the list that directly addresses the measurement needed for evaluating lens warpage.