Characterization of Retinal Microvascular and Choroidal Structural Changes in Parkinson Disease

Abstract

IMPORTANCENoninvasive retinal imaging may detect structural changes associated with Parkinson disease (PD) and may represent a novel biomarker for disease detection.OBJECTIVE To characterize alterations in the structure and microvasculature of the retina and choroid in eyes of individuals with PD and compare them with eyes of age-and sex-matched cognitively healthy control individuals using optical coherence tomography (OCT) and OCT angiography (OCTA). DESIGN, SETTING, AND PARTICIPANTSThis cross-sectional study was conducted at the Duke Neurological Disorders Clinic in Durham, North Carolina. Individuals aged 50 years or older with a diagnosis of PD were eligible for inclusion and underwent an evaluation and diagnosis confirmation before enrollment. Control individuals aged 50 years or older and without subjective cognitive dysfunction, a history of tremor, or evidence of motor dysfunction consistent with parkinsonism were solicited from the clinic or the Duke Alzheimer's Disease Prevention Registry. Individuals with diabetes, glaucoma, retinal pathology, other dementias, and corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity worse than 20/40 Snellen were excluded. Data were analyzed between January 1, 2020, and March 30, 2020.EXPOSURES All participants underwent OCT and OCTA imaging. MAIN OUTCOMES AND MEASURESGeneralized estimating equation analysis was used to characterize the association between imaging parameters and PD diagnosis. Superficial capillary plexus vessel density (VD) and perfusion density (PFD) were assessed within the ETDRS 6 × 6-mm circle, 6 × 6-mm inner ring, and 6 × 6-mm outer ring, as was the foveal avascular zone area. Peripapillary retinal nerve fiber layer thickness, macular ganglion cell-inner plexiform layer thickness, central subfield thickness, subfoveal choroidal thickness, total choroidal area, luminal area, and choroidal vascularity index (CVI) were measured.RESULTS A total of 124 eyes of 69 participants with PD (39 men [56.5%]; mean [SD] age, 71.7 [7.0] years) and 248 eyes of 137 control participants (77 men [56.2%]; mean [SD] age, 70.9 [6.7] years) were analyzed. In the 6 × 6-mm ETDRS circle, VD (β coefficient = 0.37; 95% CI, 0.04-0.71; P = .03) and PFD (β coefficient = 0.009; 95% CI, 0.0003-0.018; P = .04) were lower in eyes of participants with PD. In the inner ring of the 6 × 6-mm ETDRS circle, VD (β coefficient = 0.61; 95% CI, 0.20-1.02; P = .003) and PFD (β coefficient = 0.015; 95% CI, 0.005-0.026; P = .004) were lower in eyes of participants with PD. Total choroidal area (β coefficient = -1.74 units 2 ; 95% CI, −3.12 to −0.37 units 2 ; P = .01) and luminal area (β coefficient = -1.02 units 2 ; 95% CI, −1.86 to −0.18 units 2 ; P = .02) were greater, but CVI was lower (β coefficient = 0.5%; 95% CI, 0.2%-0.8%; P < .001) in eyes of individuals with PD.CONCLUSIONS AND RELEVANCE This study found that individuals with PD had decreased retinal VD and PFD as well as choroidal structural changes compared with age-and sex-matched control participants. Given the ...

Foveal Remodeling of Retinal Microvasculature in Parkinson’s Disease

“…Studying the morphometric variations of capillary networks in PD might provide key information about the regional neuronal structure, and the basis for investigating retinal vascular morphological features as potential biomarkers of cerebral microcirculation in PD. Although to date few studies have explored retinal vascular alterations in PD using OCT-A, the observations so far support the view that retinal vascular alterations are present in PD (Kromer et al, 2016;Kwapong et al, 2018;Rascunà et al, 2020;Shi et al, 2020;Zou et al, 2020;Robbins et al, 2021).…”

“…However, these correlations were mostly restricted to the foveal zone, and in the present study, we showed that such associations were not specific to PD, as they were also observed in controls. More recently, Robbins et al (2021) used larger sample sizes, including 124 eyes of 69 PD patients and 248 eyes of 137 controls, concluding that retinal superficial capillary vessel density and perfusion density around the foveal zone are decreased in PD compared to age and sex-matched control participants, but no correlation analyses with retinal thickness were performed. Intriguingly, we observed that the association between parafoveal GCIPL thickness and microvascular parameters in PD was mainly driven by PD-MCI patients, whose parafoveal GCIPL was significantly reduced compared to PD-NC patients.…”

Applicability of optical coherence tomography angiography (OCTA) imaging in Parkinson’s disease

“…They described a reduced retinal microvascular density in PD patients as well as a correlation between microvascular impairment and inner retinal thinning. Recently, Robbins and co-workers confirmed these OCTA findings 16 . Apart from this work, previous studies on the retina in PD patients were exclusively based on structural OCT scans.…”

“…This could be at least considered when focusing on quantitative OCTA analyses in PD patients, but needs to be weighed up against the risk of accidents due to blurry vision, especially in a motorically handicapped cohort. Interestingly, the status of the pupil during examinations was neither reported by Kwapong and colleagues nor Robbins and co-workers 15,16 .…”

“…Several OCTA studies reported on Alzheimer's disease and found a reduced retinal flow density 13,14 . However, corresponding data on PD is sparse, as to date, only two groups reported on retinal microvascular abnormalities in PD patients using OCTA 15,16 .…”