Corneal Nerve Fiber Length, Density Differ in Patients with Parkinson Disease

Corneal biomarkers can offer insight into Parkinson disease severity.

Impairment of the corneal nerves in patients with Parkinson disease (PD) correlates with severity grades, according to findings presented at the American Academy of Ophthalmology (AAO) 2022 annual meeting, held in Chicago from September 30 to October 3.

Researchers conducted a study to observe the clinical characteristics of corneal nerve parameters in PD compared with age-matched healthy controls by laser confocal microscopy. 

The study included 16 participants with PD and 18 additional participants as a  healthy control group. The Movement Disorders Society-Unified Parkinson Disease Rating Scale (MDS-UPDRS), as well as demographic data and PD clinical examinations, including Hoehnand Yahr (H&Y) staging, were performed by a movement disorder specialist. 

Parameters of the corneal nerve were also obtained, including corneal nerve fiber length (CNFL), corneal nerve fiber density (CNFD), tortuosity, and branching. A multilevel mixed model was used to match eyes. 

The researchers found differences between PD and controls in CNFL (P <.0001) and CNFD (P <.0001), as well as correlations between multiple corneal nerve parameters and H&Y grading, motor scale, smelling score, depression score, total levodopa dose, corneal sensitivity, and OSDI score.


Yaisawang S, Sringean J, Kasetsuwan N, Pongpirul K., Reinprayoon U, Bhidayasiri R. The corneal analysis in PD patients compared to age-matched healthy controls. Poster presented at: The American Academy of Ophthalmology (AAO) 2022 annual meeting; September 30-October 3; Chicago. PO073