Your health care professional will ask you about your symptoms, your vision, and your health in general. Your doctor, or an eye specialist, will use an instrument that magnifies the surface of the cornea to look for a tiny ulcer caused by viral infection. This ulcer when due to herpes simplex tends to send out star-like branches, and is best seen after a dye is used to stain the cornea temporarily. Herpes simplex infection of the cornea may be accompanied by infection of the eyelid. In this case, tiny, painful blisters resembling cold sores of the lips may appear on the eyelid.
Your doctor also may:
Test your visual sharpness and clearness (visual acuity)
Test of how well your pupil responds to light
Examine your eye using a special instrument called a slit lamp
Gently swab inside the eyelid to get a sample to send to the laboratory for culture.