ORIGINAL RESEARCH article
Front. Neuroimaging
Sec. Clinical Neuroimaging
Deciphering Neurodegeneration in Parkinson's Disease: A Comprehensive OCT Analysis of Retinal Structural Changes
- SP
Stefano Pio 1
- MS
Marco Simonelli 2
- PS
Patrizia Sucapane 3
- CS
Cesarano Simone 1
- LS
Lelio Sabetti 1
- FP
Francesca Pistoia 1
1. University of L'Aquila, L'Aquila, Italy
2. Universita degli Studi di Trieste, Trieste, Italy
3. Ospedale S.Salvatore, L'Aquila, Italy
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Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder characterized by motor and non-motor symptoms. No reliable biomarkers are currently available for early diagnosis or disease monitoring. As the retina is embryologically and anatomically part of the central nervous system, its alterations may mirror neurodegenerative processes occurring in PD. Optical coherence tomography (OCT) is a noninvasive imaging technique that allows detailed assessment of retinal layers and may serve as a source of imaging biomarkers. The aim of this study was to identify OCT-detectable retinal alterations in patients with PD and to investigate their relationship with disease phenotype, severity, and pharmacological treatment. In this cross-sectional study, 46 patients with PD underwent neurological and ophthalmological evaluation, including spectral-domain OCT, and were compared with 46 healthy controls without systemic or ocular comorbidities. Retinal layer thicknesses were analyzed using Early Treatment Diabetic Retinopathy Study (ETDRS) sectors and Garway-Heath peripapillary classification. Patients with PD showed significant reduction of thickness in sector TI in pRNFL layers as compared to healthy controls. Phenotypic analysis did not demonstrate significant retinal alterations in the akinetic-rigid dominant phenotype compared to the tremor-dominant phenotype. Correlations between retinal thickness, Montreal Cognitive Assessment (MoCA) scores, Unified Parkinson's Disease Rating Scale (UPDRS) motor scores, and levodopa daily dose equivalent (LEDD) suggested a negative correlation for LEDD in the PD group for the RPE sector. These findings support the role of retinal OCT as a valuable tool for identifying structural biomarkers of neurodegeneration in Parkinson's disease.
Summary
Keywords
biomarkers, Dopamine, neurodegeneration, Optical Coherence Tomography, Parkinson's disease, Retina, retinal nerve fiber layer
Received
30 January 2026
Accepted
25 May 2026
Copyright
© 2026 Pio, Simonelli, Sucapane, Simone, Sabetti and Pistoia. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Francesca Pistoia
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