Corneal Sensitivity and Tear Function in Neurodegenerative Diseases

Purpose: To measure corneal sensitivity and tear function in neurodegenerative diseases (NDs) and to compare them with age and sex-matched controls. Methods: Twenty patients with Alzheimer's disease (AD), 20 patients with multiple sclerosis (MS), 30 patients with Parkinson's disease (PD), 10 patients with Friedreich's ataxia (FA) and 21 patients with epilepsy (EP) who were recruited from the Kirikkale University Neurology Department during 2012 were included in this prospective study. Five groups of age and sex-matched subjects were selected as controls. Corneal sensitivity was measured using a Cochet-Bonnet esthesiometer. Tear function tests included tear break-up time (TBUT) and Schirmer's 1 tests. Results: Compared to their controls, mean corneal sensitivity was significantly reduced in AD, MS, PD and EP patients (all p<0.05), mean TBUT level was significantly shorter in patients with AD and MS (all p<0.05) and mean Schirmer's 1 test score was significantly lower in EP patients (p<0.05). When all groups were compared with each other, reduction of mean corneal sensitivity in AD and PD groups were significantly more than in FA and MS groups (overall p = 0.034). Mean TBUT levels in AD, MS and PD groups were significantly shorter than in FA and EP groups (overall p = 0.001). Mean Schirmer's 1 test scores in AD and PD groups were significantly lower than in MS, FA and EP groups (overall p = 0.040). Conclusions: Neurodegenerative diseases may be associated with reduced corneal sensitivity and abnormal tear function.