Evaluation of corneal sublayers thickness and corneal parameters in patients with Parkinson's disease

The aim of this study was to compare the blink rate (BR), tear tests, corneal parameters, and the thickness of each corneal sublayer in patients with Parkinson's disease (PD) and healthy individuals.

A total of 64 eyes from 64 patients with PD and 64 eyes from 64 age- and sex-matched healthy individuals were included in this study. All participants underwent a detailed neurological and ophthalmological evaluation. The severity of disease was measured according to Hoehn-Yahr (H-Y) scale. The blink rate (BR), Schirmer test, and tear break-up time (TBUT) scores were assessed. Corneal parameters were measured using Pentacam. Additionally, the thickness of the corneal epithelium, Bowman layer, stroma, and Descemet membrane-endothelium complex were measured on the central cornea with anterior segment module of spectral domain optical coherence tomography (AS-OCT).

The BR, Schirmer's test, TBUT, pachymetric measurements, Bowman layer, and stromal thickness values of the patient group were significantly lower than those of the control group. The disease duration and disease severity were significantly negative correlated with the pachymetric measurements and stromal thickness. Also, the values of TBUT and the score of Schirmer test were significantly positive correlated with the pachymetric measurements and stromal thickness.

A reduced BR and poor tear quality in the PD, can result in reduced pachymetric measurements and stromal thickness.