Retinal Thickness and Microvascular Pattern in Early Parkinson's Disease

Area of Science:

• Ophthalmology
• Neurology
• Medical Imaging

Background:

• Previous studies noted intraretinal layer thinning in Parkinson's disease (PD) patients compared to healthy controls (HCs).
• Limited research has explored the relationship between retinal thickness and microvascularization in PD.

Purpose of the Study:

• To assess retinal layer thickness and microvascular patterns in early PD patients and HCs.
• To investigate the correlation between retinal thickness and microvascularization in PD.
• To evaluate the retina as a potential biomarker for PD.

Main Methods:

• Utilized spectral-domain optical coherence tomography (SD-OCT) for retinal layer thickness assessment.
• Employed SD-OCT-angiography (SD-OCT-A) to analyze retinal microvascularization.
• Included patients with clinically established/probable PD and HCs, excluding those with visual system-impairing conditions.

Main Results:

• PD patients exhibited thinner peripapillary and macular retinal nerve fiber layer (RNFL), ganglionic cell layer (GCL), inner plexiform layer (IPL), and inner nuclear layer (INL) compared to HCs.
• A positive correlation was observed between RNFL, GCL, and IPL thickness and foveal microvascular density in PD patients, even after adjusting for age, sex, and hypertension.
• These findings were present in early-stage PD and unaffected by dopaminergic treatment.

Conclusions:

• The retina shows measurable structural and vascular changes in early Parkinson's disease.
• Retinal thickness and microvascular density are correlated in PD patients.
• The retina may serve as a valuable biomarker for the early detection and monitoring of Parkinson's disease progression.