Which test would best assess corneal sensation?

• A. Cotton swab testing
• B. Slit lamp examination
• C. Intraocular pressure measurement
• D. Snellen visual acuity

Answer: (A)

Corneal sensation is checked by testing the tactile sensation of the cornea to gauge the function of the sensory (trigeminal) innervation. The simplest and quickest way to do this is with a small cotton wisp lightly touched to the cornea, watching for a patient-reported sensation or an intact blink reflex. This directly assesses the sensory input from the cornea.

Slit lamp examination looks at the cornea’s structure and surface abnormalities but does not measure how well the cornea can sense stimuli. Intraocular pressure measurement evaluates the eye’s pressure, not sensory nerve function. Snellen visual acuity tests how clearly a person sees but provides no information about corneal sensation. Thus, cotton wisp testing best assesses corneal sensation.