Optical coherence tomography may assist early Parkinson’s detection

Key takeaways:

• More than 240,000 individuals from two studies were examined for retinal markers indicating Parkinson’s disease.
• Those with PD had thinner ganglion cell-inner plexiform and inner nuclear layers in retinas.

Individuals with Parkinson’s disease present with reduced thickness of two key components of the retina, which may indicate retinal optical coherence tomography as a vital tool in early disease detection, data show.

“Stimulated by the postmortem finding of reduced dopamine content in the retina of people with Parkinson’s disease, researchers have sought evidence of retinal changes on in vivo imaging techniques, such as optical coherence tomography,” Siegfried Karl Wagner, MSc, MD, of the Institute of Ophthalmology at University College London, and colleagues wrote in Neurology.

Wagner and colleagues aimed to assess whether inner retinal anatomy, measured using optical coherence tomography (OCT), can detect Parkinson’s disease (PD) in live volunteers.

They conducted a cross-sectional analysis utilizing data from two studies. One was the AlzEye for retinal markers in PD, a retrospective cohort of 154,830 patients (700 with PD, 105,770 controls; 51.7% female) aged 40 years and older attending secondary care ophthalmic hospitals in London between 2008 and 2018. The other was the UK Biobank for retinal markers in incident PD, a prospective population-based cohort of 67,311 volunteers (50,405 individuals fit inclusion criteria; median age 56.1 years; 54.7% female) who were recruited between 2006 and 2010 and underwent retinal imaging.

Macular retinal nerve fiber layer (mRNFL), ganglion cell-inner plexiform layer (GCIPL), and inner nuclear layer (INL) thicknesses were extracted from fovea-centered OCT. The researchers employed linear mixed effects models to analyze associations between prevalent PD and retinal thicknesses, while frailty models were utilized to estimate hazard ratios for the association between time to PD diagnosis and retinal thickness.

According to results, participants with prevalent PD had thinner GCIPL (-2.12 m; 95% CI, -3.17, -1.07) and INL (-0.99 m, 95% CI: -1.52, -0.47).

Among those in the UK Biobank, 53 developed PD at a mean of 2,653±851 days. Thinner GCIPL (HR = 0.62 per standard deviation increase; 95% CI, 0.46, 0.84) and thinner INL (HR = 0.7; 95% CI, 0.51, 0.96) were also associated with incident PD.

“Further studies exploring the chronological sequence of retinal sublayer thickness would help elucidate the mechanism and determine whether retinal imaging could support diagnosis, prognosis and complex management of patients affected by Parkinson’s,” Wagner and colleagues wrote.