Diagnosis of photokeratitis involves a thorough examination by an eye doctor. The patient's history, especially recent exposure to intense UV light or sunlight without proper eye protection, can be a telling indicator. The eye doctor might use a slit lamp, a device that shines a bright light into the eye, to closely examine the cornea and detect any signs of damage or inflammation. The slit lamp allows the optometrist to view the eye in detail, including the cornea, conjunctiva, and eyelids, which might exhibit signs of UV damage.