Parafoveal thinning of inner retina is associated with visual dysfunction in Lewy body diseases

Abstract

Background Retinal optical coherence tomography findings in Lewy body diseases and their implications for visual outcomes remain controversial. We investigated whether region‐specific thickness analysis of retinal layers could improve the detection of macular atrophy and unravel its association with visual disability in Parkinson's disease. Methods Patients with idiopathic Parkinson's disease (n = 63), dementia with Lewy bodies (n = 8), and E46K mutation carriers in the α‐synuclein gene (E46K‐SNCA) (n = 4) and 34 controls underwent Spectralis optical coherence tomography macular scans and a comprehensive battery of visual function and cognition tests. We computed mean retinal layer thicknesses of both eyes within 1‐, 2‐, 3‐, and 6‐mm diameter macular discs and in concentric parafoveal (1‐ to 2‐mm, 2‐ to 3‐mm, 1‐ to 3‐mm) and perifoveal (3‐ to 6‐mm) rings. Group differences in imaging parameters and their relationship with visual outcomes were analyzed. A multivariate logistic model was developed to predict visual impairment from optical coherence tomography measurements in Parkinson's disease, and cutoff values were determined with receiver operating characteristic analysis. Results When compared with controls, patients with dementia with Lewy bodies had significant thinning of the ganglion cell–inner plexiform layer complex within the central 3‐mm disc mainly because of differences in 1‐ to 3‐mm parafoveal thickness. This parameter was strongly correlated in patients, but not in controls, with low contrast visual acuity and visual cognition outcomes (P < .05, False Discovery Rate), achieving 88% of accuracy in predicting visual impairment in Parkinson's disease. Conclusion Our findings support that parafoveal thinning of ganglion cell–inner plexiform complex is a sensitive and clinically relevant imaging biomarker for Lewy body diseases, specifically for Parkinson's disease. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Retinal Thickness Predicts the Risk of Cognitive Decline in Parkinson Disease

“…More recent publications have shown that the thinning of macular GCIPL in PD is linked to cognitive impairment in de novo patients 23 and to the risk of dementia 18 . Interestingly, our group found that visual dysfunction in PD is selectively associated with the thinning of GCIPL in the 1‐ to 3‐mm diameter ring area around the fovea (parafoveal GCIPL), 20 an OCT feature that has also been identified in patients with idiopathic rapid eye movement sleep behavior disorder—the earliest (prodromal) phase of LBD 24 . So far, only few OCT studies have prospectively evaluated the progression of retinal thinning in PD patients, 25–27 and none has specifically looked at the rate of macular GCIPL atrophy and its relationship with disease worsening.…”

“…Macular and peripapillary OCT images were acquired for each eye using Spectralis spectral‐domain OCT (SD‐OCT; Heidelberg Engineering, Heidelberg, Germany), and thickness measures were calculated for peripapillary retinal nerve fiber layer (pRNFL) and for different combinations of layers and regions of the macula, as previously described 20 . Briefly, macular scans consisted of 25 single horizontal axial scans covering a 20° × 20° area (512 A‐scans per B‐scan and 49 frames per B‐scan).…”

“…The score of MoCA was considered to have declined if there was a reduction of 4 points or more, based on the upper limit of the lowest quartile of MoCA score changes across 2 timepoints in LBD patients. Predictor categorization was based on baseline measurements; we averaged baseline z scores of low‐contrast visual acuity and visual cognition tests in LBD patients for classifying iPD patients into 2 groups using K‐means clustering, 20 and including DLB and E46K‐ SNCA within the classification as models. Also, iPD patients were categorized into retinal thickness tertiles.…”

“…In line with this, the atrophy of macular ganglion cell–inner plexiform layer complex (GCIPL) measured with optical coherence tomography (OCT) has been shown to be a good marker of visual dysfunction in PD, 20 but the link between macular GCIPL thinning and overall cognitive impairment is poorly understood. Retinal neurodegeneration, neuronal loss, and anomalous α‐synuclein deposits within inner retinal layers are now well‐known pathological features of LBD patients 21 .…”

Contribution of the GABAergic System to Non-Motor Manifestations in Premotor and Early Stages of Parkinson’s Disease

“…In vivo neuroimaging studies in newly diagnosed and drug-naïve PD patients have detected structural alterations in the visual pathway, ranging from thinning of inner retinal layers to increased optic radiation mean diffusivity and reduced visual cortical volumes (Arrigo et al, 2017; Ahn et al, 2018; Murueta-Goyena et al, 2019), which might explain some visual disturbances. There is, however, a growing body of evidence highlighting the role of GABA in perceptual aspects of vision.…”