Certified Ophthalmic Technician (COT) Test 2025 – 400 Free Practice Questions to Pass the Exam

An abnormal result on an electroretinogram (ERG) indicates potential retinal dysfunction. The ERG is a test that measures the electrical responses of the retina's light-sensitive cells (photoreceptors). When these responses are abnormal, it can suggest various issues, such as damage or disease affecting the retina, including conditions like retinitis pigmentosa, diabetic retinopathy, or other types of retinal degeneration.

The other options relate to visual function assessments but do not accurately describe the implications of an abnormal ERG. For example, normal visual function would typically indicate a healthy retina, and corneal opacity is associated with issues in the corneal layer of the eye rather than the retina. Similarly, healthy visual acuity refers to the sharpness of vision but does not provide information about the retinal health, thus reinforcing that an abnormal ERG is specifically linked to potential issues within the retinal structures.