Ane Murueta‐Goyena, Rocío Del Pino, Marta Galdós, Begoña Arana, Marian Acera, Mar Carmona‐Abellán, Tamara Fernández‐Valle, Beatriz Tijero, Olaia Lucas‐Jiménez, Natalia Ojeda, Naroa Ibarretxe‐Bilbao, Javier Peña, Jesus Cortes, Unai Ayala, Maitane Barrenechea, Juan Carlos Gómez‐Esteban, and Iñigo Gabilondo. Retinal Thickness Predicts the Risk of Cognitive Decline in Parkinson Disease. Annals of neurology 89: 165-176, 2021 [pdf]
Objective: This study was undertaken to analyze longitudinal changes of retinal thickness and their predictive value as biomarkers of disease progression in idiopathic Parkinson’s disease (iPD).
Methods: Patients with Lewy body diseases were enrolled and prospectively evaluated at 3 years, including patients with iPD (n = 42), dementia with Lewy bodies (n = 4), E46K-SNCA mutation carriers (n = 4), and controls (n = 17). All participants underwent Spectralis retinal optical coherence tomography and Montreal Cognitive Assessment, and Unified Parkinson’s Disease Rating Scale score was obtained in patients. Macular ganglion cell–inner plexiform layer complex (GCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thickness reduction rates were estimated with linear mixed models. Risk ratios were calculated to evaluate the association between baseline GCIPL and pRNFL thicknesses and the risk of subsequent cognitive and motor worsening, using clinically meaningful cutoffs.
Results: GCIPL thickness in the parafoveal region (1- to 3-mm ring) presented the largest reduction rate. The annual- ized atrophy rate was 0.63μm in iPD patients and 0.23μm in controls (p < 0.0001). iPD patients with lower parafoveal GCIPL and pRNFL thickness at baseline presented an increased risk of cognitive decline at 3 years (relative risk [RR] = 3.49, 95% confidence interval [CI] = 1.10–11.1, p = 0.03 and RR = 3.28, 95% CI = 1.03–10.45, p = 0.045, respec- tively). We did not identify significant associations between retinal thickness and motor deterioration. Interpretation: Our results provide evidence of the potential use of optical coherence tomography–measured parafoveal GCIPL thickness to monitor neurodegeneration and to predict the risk of cognitive worsening over time in iPD.