Ulcerative keratitis, also referred to as corneal ulcer, is an acute, progressive and painful peripheral ulcer of the cornea. It mainly afects only adults and is difcult to treat. It usually afects one eye or both eyes successively with an interval of several years. The ulcer develops from the periphery to the center and is extremely painful. In general, if there is no secondary infection, it will not perforate the eye, but it can erode the entire corneal surface, and eventually form an extensive corneal scar, which afects the vision seriously. The ulcers may be caused by an infection or an abrasion, but ofen, the etiology remains unknown. Recent research suggests that there may be an underlying immune conditions, a possible association with the hepatitis C virus or vitamin A defciency.

The features of the disease are similar to the TCM pattern huā yì bái xiàn (花翳白陷, petaloid nebula with a sunken center), which is a condition characterized by nebulae in the cornea that is raised on the sides, sunken in the center and is fowershaped. It changes and grows rapidly. Due to its rapid onset, and the severity of the condition it requires immediate treatment. If treatment is delayed, it can develop into purulent keratitis; which presents with an upward rushing purulent fuid along with a shrinking pupil. If rupture of the cornea occurs, corneal perforation and iridoptosis may also occur. Even afer recovery, it may result in a thick nebula that severely afects visual acuity.

This condition is usually caused by hidden fre in the liver channel combined with atack of external wind evil. This results in external wind heat pathogen in the lung and liver channels that travels upward to the eyes. Alternatively, accumulation of heat in the zang-fu organs combined with external evil entering the interior can cause excessive heat to ascend the eyes. Furthermore, if there is yang defciency, it can lead to cold evil damaging the liver channel and invading upwards to the eyes.