A tentative mechanism for inferior punctate keratopathy

We analyzed the blinking motions of ten patients with inferior punctate keratopathy and ten normal subjects by means of time-lapse motion pictures. We also determined the frequency of blinking during one-minute intervals for each individual. Four types of blinking were distinguished: complete, incomplete, twitch, and forced blink. The average blinking frequency was about the same for both groups: 16 to 17 blinks per minute. The relative proportion of complete blinks, however, was much lower in patients with inferior punctate keratopathy than in normal subjects. The impaired blinking motion may be responsible for the punctate staining of the inferior corneal epithelium by producing exposure and inadequacies in the tear film. For this reason, these patients may benefit from blink training, application of tear substitutes, or soft contact lenses more than from the customary prescription of topical cortisone eyedrops.