Although the underlying cause of PD is not understood and not all accepted biomarkers are available for in vivo diagnosis of PD, evidence suggests that cerebral vascular disease is a potential risk factor. be there for PD. Patients with PD are also more prone to ischemic cerebral diseases.
“Diagnosis of PD is complex because it is similar to other parkinsonian conditions, including multisystemic atrophy, progressive supranuclear palsy, and corticobasal degeneration,” the researchers explained, while “noninvasive tests to develop confidence in PD judgment remains a key unmet need. ”
However, further research has suggested that structural and functional changes in the retina may act as a surrogate biomarker for cerebral vascular changes and global neurodegeneration in patients with PD.
To identify changes in the structure and microvasculature of the retina and choroid in the eyes of people with PD, the researchers used optical coherence tomography and optical coherence tomography angiography. They then compared results with control eyes.
Participants in the study group (n = 69) were age 50 or older, had PD, and were recruited from Duke Neurological Problems Clinic in Durham, North Carolina. Healthy volunteers age 50 or older with no subjective mental disorder, history of tremor, or evidence of motor deficit made up the control group (n = 137).
Any participants with a history of diabetes, glaucoma, retinal pathology, or visual examination Corrected Diabetic Early Retinopathy Study (ETDRS) worse than 20/40 Snellen were excluded. At the time of image taking, participants underwent a mental assessment using the Mini-Mental State Survey, where a higher score (0–30) indicates better performance.
VD and PFD were measured in ETDRS grid regression. “Vessel density was defined as the total length of perfused vasculature per unit area in the measurement section,” the authors wrote. “Pour density is defined as the percentage of spread vasculature per unit area in a measurement area.”
A total of 124 eyes from patients with PD and 248 control eyes were evaluated. The researchers found:
- 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) lower in the 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) lower in the eyes of participants with PD
- Total choroidal range (β coefficient = –1.74 pixels2; 95% CI, −3.12 to −0.37 pixels2; P.= .01) and luminal area (β coefficient = –1.02 pixels2; 95% CI, −1.86 to −0.18 pixels2; P.= .02) larger in the eyes of those with PD
- Individuals with PD had a lower vascularoid index (β coefficient = 0.5%; 95% CI, 0.2% –0.8%; P <.001).
However, the area under the receptor of character analyzes found that “individual retinal parameters may not have sufficient discriminatory capacity to function as an independent biomarker of disease with defined cutoff values that explain presence or absence of disease. ”
But when combined with clinical history and other existing trials, the researchers argued that the results of choroidal and retinal microscopic imaging may have the potential of clinicians’ confidence in experiencing it. PD.
“Longitudinal studies are needed that characterize the natural history of microscopic and retinal structural changes in individuals across the PD clinical spectrum,” they concluded. “Such studies may clarify whether these imaging findings could be useful as biomarkers for PD onset or the rapid decay from PD. ”
Information:
Robbins CB, Thompson AC, Bhullar PK, et al. Characterization of retinal and choroidal microvascular structural changes in Parkinson’s disease. Ophthalmol JAMA. Published online December 23, 2020. doi: 10.1001 / jamaophthalmol.2020.5730