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

Patients with glaucoma often require a threshold 24-degree central field test because this specific visual field testing method is designed to detect and quantify the loss of peripheral vision and sensitivity, which is crucial in glaucoma management. Glaucoma is characterized by a progressive loss of retinal ganglion cells and subsequent visual field deterioration. The 24-2 test, which focuses on a central field of 24 degrees, allows for detailed evaluation of visual field loss, particularly in the central and paracentral areas where glaucoma typically manifests first.

In contrast, cataracts primarily affect visual acuity and quality of vision but do not inherently cause peripheral vision loss, making this test less relevant for their assessment. Patients with retinal detachment may also experience visual field loss, but the pattern and type of testing done will depend on the specific circumstances of the detachment. Similarly, while macular degeneration affects central vision and may involve some peripheral loss, the threshold testing specifically used for glaucoma is tailored to monitor the particular deficits associated with that condition, making it the most applicable scenario for the need of a threshold 24-degree central field test.