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Can You Get Parkinson’s Disease in the Future? A Detection Through Your Eye

by | Aug 1, 2025 | Manuscripts | 0 comments

Lanisha Blessy Coelho, M.Optom.

Assistant Professor, ITM Vocational University, Vadodara, India

 

Oculomics, the study of eye-related biomarkers, explores macroscopic, microscopic, and molecular features of the eye to understand systemic diseases. The retina, as an accessible extension of the brain, provides a unique opportunity for non-invasive, real-time assessment of the central nervous system’s structure and function. The primary goal of oculomics is to develop rapid, cost-effective biomarkers to screen and diagnose diseases, including Parkinson’s Disease (PD). (1)

Optical Coherence Tomography (OCT) and OCT Angiography (OCTA) have been pivotal in advancing this field by generating “retinal fingerprints” that indicate systemic conditions. These technologies offer significant promise for early detection of PD. (2)

Parkinson’s Disease and Visual Manifestations

Parkinson’s disease, the second most common neuro-degenerative disorder after Alzheimer’s, primarily manifests with motor symptoms like tremors, bradykinesia, and stiffness. However, visual symptoms such as reduced colour discrimination, motion perception, visual acuity, and contrast sensitivity often precede motor signs, under-scoring the potential for early detection (Figure 1). (3)

Figure 1. Symptoms observed in eyes of Parkinson’s disease
Image Courtesy:
 (Created by Author)

Dopamine, essential for retinal function and visual processing, modulates photoreceptor activity, melatonin synthesis, and light adaptation. Its deficiency in PD leads to impaired visual functions, including hypometric saccades, eyelid apraxia, blepharospasm, and dry eyes. Retinal dopaminergic neurons are notably affected due to neuro-degeneration and alpha-synuclein aggregation (Figure 2). (4,5)

Figure 2: Dopamine Interacting with Normal Neurons versus Parkinson Disease Neurons
Image Courtesy:
(Created by Author)

Associated Disorders and Ocular Biomarkers

Several disorders linked to atypical Parkinsonism, such as Progressive Supranuclear Palsy (PSP) and Multiple System Atrophy (MSA), show distinctive ocular motor impairments, aiding differential diagnosis. Corneal biomarkers, such as reduced thickness and sub-basal nerve density, also suggest peripheral neuropathy in PD. (6)

PD patients have a 30% higher incidence of glaucoma, attributed to lower catecholamine levels and oxidative stress. Similarly, the risk of cataract formation is 1.48 times higher due to shared pathological pathways involving alpha-synuclein and oxidative damage. (7)

Advances in Early Detection

Recent studies have identified markers of Parkinson’s in retinal scans up to seven years before clinical diagnosis. Research from Moorfields Eye Hospital and the UCL Institute of Ophthalmology highlights the potential of OCT and OCTA, enhanced by Artificial Intelligence (AI), in detecting early retinal changes (Figure 3). (2,8)

Additionally, researchers at the Southeast Parkinson’s Disease Research Centre, in collaboration with Virginia Commonwealth University, developed eye-tracking systems to analyse subtle abnormalities in eye movements. Motion-tracking cameras detect patterns like increased latency and hypometric saccades, offering accurate and early diagnosis. (9)

Conclusion

The integration of ocular biomarkers and advanced imaging technologies provides a transformative approach to early Parkinson’s detection. Combining retinal imaging, eye-tracking systems, and AI enables timely interventions, potentially slowing disease progression and improving outcomes. These advancements represent a critical leap forward in the management of neuro-degenerative diseases.

By focusing on ocular health, we are not only refining diagnostic practices but also paving the way for innovative therapeutic avenues that prioritise the well-being of individuals at risk for Parkinson’s and related conditions.

 

References:

  1. Honavar, S. G. (2022). Oculomics – The eyes talk a great deal. Indian Journal of Ophthalmology, 70(3), 713. https://doi.org/10.4103/ijo.IJO_474_22
  2. Salehi, M., Rezagholi, F., Zakavi, S., Jahanshahi, A., Gouravani, M., Yazdanpanah, G., Seddon, I., Jabbehdari, S., & Singh, R. (2023). Optical coherence tomography angiography measurements in Parkinson’s disease: A systematic review and meta-analysis. Eye (London, England), 37. https://doi.org/10.1038/s41433-023-02483-2
  3. Doke, R., Sonawane, S., Thorat, V., Bhabad, S., Lamkhade, G., Jadhav, S., Jain, R., & Bhagwat, A. (2023). Through the eyes of Parkinson’s: A narrative review of clinical spectrum and ophthalmological challenges in Parkinson’s disease. Indian Journal of Clinical and Experimental Ophthalmology, 9(4), 489–494. https://doi.org/10.18231/j.ijceo.2023.094
  4. Devi, S., Mahalaxmi, I., Aswathy, N. P., Dhivya, V., & Balachandar, V. (2020). Does retina play a role in Parkinson’s disease? Acta Neurologica Belgica, 120(2), 257–265. https://doi.org/10.1007/s13760-019-01197-4
  5. Popova, E. (2020). Role of dopamine in retinal function. In Kolb, H., Fernandez, E., & Jones, B. (Eds.), Webvision: The Organization of the Retina and Visual System [Internet]. Salt Lake City, UT: University of Utah Health Sciences Center. https://webvision.med.utah.edu
  6. Ramirez, A. I., DeHoz, R., Salobrar-Garcia, E., Salazar, J. J., Rojas, B., Ajoy, D., et al. (2017). The role of microglia in retinal neurodegeneration: Alzheimer’s disease, Parkinson, and glaucoma. Frontiers in Aging Neuroscience, 9, 214. https://doi.org/10.3389/fnagi.2017.00214.
  7. Lee, K., Lee, G., Lee, S., & Park, C. Y. (2022). Advances in ophthalmic drug delivery technology for postoperative management after cataract surgery. Expert Opinion on Drug Delivery, 19(8), 945–964. https://doi.org/10.1080/17425247.2022.2092976
  8. Eye scans detect signs of Parkinson’s disease. (n.d.). Moorfields Eye Hospital. Retrieved January 24, 2025, from https://www.moorfields.nhs.uk/about-us/news-and-blogs/news/eye-scans-detect-signs-of-parkinson-s-disease-up-to-seven-years-before-diagnosis
  9. Eye-tracking device for early Parkinson’s detection. (2020, January 24). U.S.DepartmentofVeteransAffairs. https://www.research.va.gov/research_in_action/Eye-tracking-device-for-early-Parkinsons-detection.cfm

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