Central corneal thickness and its relationship to Parkinson’s disease severity

Evaluation of corneal parameters in patients with Parkinson’s disease

“…In our study, the scores of TBUT and Schirmer test were significantly lower and the scores of corneal fluorescein staining and OSDI were significantly increased in patients with PD comparison to the controls. Our findings agree with the pre-vious researches [8,19,[23][24][25] suggesting that PD patients may have deficits in aqueous tear production and in the tear film mucin layer. Abnormalities of the tear film in PD may be the result of autonomic dysfunction in lacrimal glands receiving both parasympathetic and sympathetic innervation and the result of reduced blink rate impairing meibomian gland function [3].…”

“…Fitzpatrick assessed the BR in patients with PD during different tasks such as watching a video, being interviewed, and reading from a book and found that BR was significantly reduced in the patients with PD compared to the healthy controls for each of the test conditions but there was no effect of disease duration, severity or treatment on BR [20]. As previously described [8,[18][19][20], in our study, we found that the patients with PD had significantly reduced BR than healthy controls and there was a significantly negative association between the BR and disease severity.…”

“…Blinking provides a regular precorneal tear film, smoothing out irregularities of corneal surface and also preserves a symmetric tear-cornea optical interface [17]. Studies reported that patients with PD had reduced blink rates compared to normal subjects, with longer pauses in voluntary blinking, small amplitude and peak velocity in spontaneous blinking [8,18,19]. A decreased BR is thought to be one of the clinical features of PD [20].…”

“…Reduced blinking in patients with PD may contribute to dry eye and disturbances the ocular surface [23]. Abnormalities in tear film tests have frequently been reported in patients with PD [8,21,23]. Ç omoglu et al found that the scores of Schirmer test were significantly decreased in the PD group than the control group [24].…”

“…Corneal thickness is significantly reduced in individuals with dry eyes [7]. One recent study evaluated central corneal thickness using an ultrasonic pachymetry in the patients with PD and the researchers found reduced central corneal thickness [8]. Although ultrasound pachymetry is frequently used for corneal thickness assessment, there are some disadvantages of ultrasonic pachymetry such as applying topical anesthesia due to the direct contact of the probe on the cornea, discomfort of the patient and difficulty in repeatability [9].…”