Changes in Corneal Sensation and Ocular Surface in Patients With Asymmetrical Keratoconus

Purpose: To describe tear function, ocular surface changes, and corneal sensitivity in patients with asymmetrical keratoconus (KC). Methods: Thirty-one patients with asymmetrical KC (31 KC and 31 subclinical KC eyes) and 30 control subjects (1 eye in each subject) were enrolled in this prospective, case-control study. The patients and control subjects underwent ocular surface examinations including corneal sensitivity measurements, the Schirmer test using topical anesthesia, tear osmolarity test, and conjunctival impression cytology. Results: Mean corneal sensitivity and Schirmer test values were significantly lower in the KC and subclinical KC eyes compared with the control eyes. The conjunctiva of KC and subclinical KC eyes showed significantly higher grades of squamous metaplasia and goblet cell loss compared with the control group. However, no significant difference in tear osmolarity was found among the groups. Conclusions: The corneal sensitivity and ocular surface changes were significant in the subclinical KC and KC eyes compared with the control subjects. Ocular surface disease in KC was characterized by tear deficiency disorder and abnormal impression cytology results. However, no significant difference in tear osmolarity was found among the groups. The decrease in corneal sensitivity and ocular surface change may be associated with the pathogenesis of ocular surface changes in KC and the progression of the disease.