Cover test is a term used in ophthalmology to diagnose eye muscle weakness or strabismus. However, there are different names for this test that mean the same thing. These include the alternate cover test, the prism cover test, and the cross-cover test. Although they may differ in the materials and procedures, they all require covering and uncovering of each eye while observing eye movements. The cover test helps the doctor evaluate how the eyes work together, detect double vision, and identify the type of eye deviation, such as esotropia (inward deviation) and exotropia (outward deviation). Using various terms for the cover test makes it easier to understand and communicate the diagnosis and treatment plan.