{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T12:28:46Z","timestamp":1781612926284,"version":"3.54.5"},"reference-count":45,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T00:00:00Z","timestamp":1770768000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"American Academy of Neurology Career Development Award"},{"name":"American Parkinson\u2019s Disease Association Cotzias Fellowship"},{"name":"Dystonia Medical Research Foundation research grant"},{"name":"Penni and Stephen Weinberg Chair in Brain Health"},{"name":"Department of Veterans Affairs Rehab R&D SPIRE Grant"},{"name":"Allan Woll Fund and Sanford Fox Family Fund"},{"name":"Cleveland Brain Health Initiative grant"},{"name":"Research to Prevent Blindness Disney Amblyopia Award"},{"name":"Artificial Intelligence in Medicine Lerner Research Grant"},{"name":"CWRU CTSC Pilot Grant Program"},{"name":"Cleveland Clinic RPC Grant"},{"name":"Departmental Grants from Research to Prevent Blindness"},{"name":"Unrestricted Block Grant CCLCM"},{"name":"NIH-NEI P30 Core Grant Award"},{"DOI":"10.13039\/100018313","name":"Cleveland Eye Bank Foundation","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100018313","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Research to Prevent Blindness International Collaborators Award"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Brain Sciences"],"abstract":"<jats:p>Background\/Objectives: Visual dysfunction is a common non-motor symptom in Parkinson\u2019s Disease (PD), as evidenced by deficits in color vision (CV) and binocular vision (BV). Computerized CV tests, such as the Cambridge Color Test (CCT), are underutilized in this patient population despite the known limitations of common CV tests. Methods: In total, 19 PD and 12 control participants underwent a comprehensive eye exam, including ocular motility testing and the CCT, utilizing thresholds obtained along 12 contrast vectors to fit a discrimination ellipse. Findings were compared across groups, and the association with disease severity was analyzed. Results: PD participants showed increases in ellipse area (p = 0.012) and short-axis length (p = 0.009). PD participants demonstrated convergence insufficiency type exotropia (p &lt; 0.001) and impaired stereopsis (p = 0.006). No significant correlation with UPDRS scores was seen for either BV or CV. Conclusions: PD participants exhibited binocular vision dysfunction with selective changes in color vision. CV changes are more variable in PD, likely due to mixed parvocellular and cortical dysfunction. Convergence insufficiency type exotropia is more common in PD, likely due to combined cortical and subcortical neurodegeneration. Both BV and CV changes occur independently of motor severity, emphasizing the need for routine visual testing regardless of symptom progression.<\/jats:p>","DOI":"10.3390\/brainsci16020213","type":"journal-article","created":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T11:13:15Z","timestamp":1770808395000},"page":"213","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Color Vision Deficits and Binocular Vision Dysfunction in Parkinson\u2019s Disease"],"prefix":"10.3390","volume":"16","author":[{"given":"Julia","family":"Mleczek","sequence":"first","affiliation":[{"name":"School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anim","family":"Forjindam","sequence":"additional","affiliation":[{"name":"School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aasef","family":"Shaikh","sequence":"additional","affiliation":[{"name":"Daroff Dell\u2019Osso Ocular Motility Laboratory, Cleveland VA Medical Center, Cleveland, OH 44106, USA"},{"name":"Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fatema","family":"Ghasia","sequence":"additional","affiliation":[{"name":"Daroff Dell\u2019Osso Ocular Motility Laboratory, Cleveland VA Medical Center, Cleveland, OH 44106, USA"},{"name":"Ocular Motility & Vision Neurosciences Laboratory, Cleveland Clinic, Cleveland, OH 44106, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1591","DOI":"10.1002\/mds.26424","article-title":"MDS clinical diagnostic criteria for Parkinson\u2019s disease","volume":"30","author":"Postuma","year":"2015","journal-title":"Mov. Disord."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"484","DOI":"10.1111\/ene.14092","article-title":"Self-reported visual dysfunction in Parkinson disease: The Survey of Health, Ageing and Retirement in Europe","volume":"27","author":"Hamedani","year":"2020","journal-title":"Eur. J. Neurol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"e1539","DOI":"10.1212\/WNL.0000000000009214","article-title":"Seeing ophthalmologic problems in Parkinson disease: Results of a visual impairment questionnaire","volume":"94","author":"Borm","year":"2020","journal-title":"Neurology"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2827","DOI":"10.1093\/brain\/aww175","article-title":"Visual dysfunction in Parkinson\u2019s disease","volume":"139","author":"Weil","year":"2016","journal-title":"Brain"},{"key":"ref_5","first-page":"S49","article-title":"Management of Visual Dysfunction in Patients with Parkinson\u2019s Disease","volume":"10","author":"Savitt","year":"2020","journal-title":"J. Park. Dis."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1390","DOI":"10.1002\/mds.27454","article-title":"Oculo-visual abnormalities in Parkinson\u2019s disease: Possible value as biomarkers","volume":"33","author":"Guo","year":"2018","journal-title":"Mov. Disord."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2243","DOI":"10.12659\/MSM.890861","article-title":"Ophthalmological features of Parkinson disease","volume":"20","author":"Nowacka","year":"2014","journal-title":"Med. Sci. Monit."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Nieto-Escamez, F., Obrero-Gait\u00e1n, E., and Cort\u00e9s-P\u00e9rez, I. (2023). Visual Dysfunction in Parkinson\u2019s Disease. Brain Sci., 13.","DOI":"10.3390\/brainsci13081173"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"101","DOI":"10.2147\/EB.S384763","article-title":"Monitoring Eye Movement in Patients with Parkinson\u2019s Disease: What Can It Tell Us?","volume":"15","author":"Sun","year":"2023","journal-title":"Eye Brain"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Kang, S.L., Shaikh, A.G., and Ghasia, F.F. (2018). Vergence and Strabismus in Neurodegenerative Disorders. Front. Neurol., 9.","DOI":"10.3389\/fneur.2018.00299"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1016\/bs.pbr.2019.05.001","article-title":"Saccades in Parkinson\u2019s disease: Hypometric, slow, and maladaptive","volume":"249","author":"Shaikh","year":"2019","journal-title":"Prog. Brain Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"424","DOI":"10.1002\/mdc3.12453","article-title":"Prevalence of Convergence Insufficiency in Parkinson\u2019s Disease","volume":"4","author":"Irving","year":"2017","journal-title":"Mov. Disord. Clin. Pract."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1080\/01658100600742838","article-title":"Parkinson\u2019s Disease and Diplopia","volume":"30","author":"Lepore","year":"2006","journal-title":"Neuro-Ophthalmology"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Gupta, P., Murray, J.M., Beylergil, S.B., Jacobs, J., Kilbane, C.W., Shaikh, A.G., and Ghasia, F.F. (2023). Objective assessment of eye alignment and disparity-driven vergence in Parkinson\u2019s disease. Front. Aging Neurosci., 15.","DOI":"10.3389\/fnagi.2023.1217765"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"110458","DOI":"10.1016\/j.exer.2025.110458","article-title":"Binocular dysfunction in Parkinson\u2019s Disease: Decoding near triad dynamics and divergence deficits","volume":"258","author":"Nambiar","year":"2025","journal-title":"Exp. Eye Res."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"442","DOI":"10.1097\/WNO.0000000000001422","article-title":"Effects of Parkinson Disease on Blur-Driven and Disparity-Driven Vergence Eye Movements","volume":"41","author":"Gupta","year":"2021","journal-title":"J. Neuroophthalmol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"0460a5","DOI":"10.1088\/1741-2552\/ac123e","article-title":"Computational models to delineate 3D gaze-shift strategies in Parkinson\u2019s disease","volume":"18","author":"Gupta","year":"2021","journal-title":"J. Neural. Eng."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1017\/S0317167100011501","article-title":"Stereopsis in Drug Na\u00efve Parkinson\u2019s Disease Patients","volume":"38","author":"Kim","year":"2011","journal-title":"Can. J. Neurol. Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1186\/2047-783X-19-29","article-title":"Stereopsis impairment is associated with decreased color perception and worse motor performance in Parkinson\u2019s disease","volume":"19","author":"Sun","year":"2014","journal-title":"Eur. J. Med. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"178","DOI":"10.1016\/j.ophtha.2011.06.040","article-title":"Ocular Motor and Sensory Function in Parkinson Disease","volume":"119","author":"Almer","year":"2012","journal-title":"Ophthalmology"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1408","DOI":"10.1136\/bjo.86.12.1408","article-title":"New Farnsworth-Munsell 100 hue test norms of normal observers for each year of age 5\u201322 and for age decades 30\u201370","volume":"86","author":"Kinnear","year":"2002","journal-title":"Br. J. Ophthalmol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1249","DOI":"10.1001\/archneur.59.8.1249","article-title":"Progressive worsening of spatial and chromatic processing deficits in Parkinson disease","volume":"59","author":"Diederich","year":"2002","journal-title":"Arch. Neurol."},{"key":"ref_23","first-page":"715","article-title":"Oculo-Visual Dysfunction in Parkinson\u2019s Disease","volume":"5","author":"Armstrong","year":"2015","journal-title":"J. Park. Dis."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"887","DOI":"10.1212\/WNL.42.4.887","article-title":"Abnormalities in color vision and contrast sensitivity in Parkinson\u2019s disease","volume":"42","author":"Price","year":"1992","journal-title":"Neurology"},{"key":"ref_25","first-page":"167","article-title":"Altered Outer Retinal Structure, Electrophysiology and Visual Perception in Parkinson\u2019s Disease","volume":"14","author":"Tran","year":"2024","journal-title":"J. Park. Dis."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1007\/s007020050007","article-title":"Effects of apomorphine on visual functions in Parkinson\u2019s disease","volume":"107","author":"Kuhn","year":"2000","journal-title":"J. Neural. Transm."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"3427","DOI":"10.1016\/S0042-6989(97)00402-1","article-title":"Colour discrimination thresholds in Parkinson\u2019s disease: Results obtained with a rapid computer-controlled colour vision test","volume":"38","author":"Regan","year":"1998","journal-title":"Vis. Res."},{"key":"ref_28","unstructured":"(Metropsis Remote Getting Started, 2020). Metropsis Remote Getting Started, version R20."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2260","DOI":"10.1093\/brain\/awh581","article-title":"Independent patterns of damage within magno-, parvo- and koniocellular pathways in Parkinson\u2019s disease","volume":"128","author":"Silva","year":"2005","journal-title":"Brain"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Bento-Torres, N.V.O., Rodrigues, A.R., C\u00f4rtes, M.I.T., Bonci, D.M.D.O., Ventura, D.F., and Silveira, L.C.D.L. (2016). Psychophysical Evaluation of Congenital Colour Vision Deficiency: Discrimination between Protans and Deutans Using Mollon-Reffin\u2019s Ellipses and the Farnsworth-Munsell 100-Hue Test. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0152214"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"636","DOI":"10.1136\/bjo.40.10.636","article-title":"The R.A.F. Near-point Rule","volume":"40","author":"Neely","year":"1956","journal-title":"Br. J. Ophthalmol."},{"key":"ref_32","unstructured":"(2017). Titmus Fly Stereotest Manual, Optical Co., Inc."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2129","DOI":"10.1002\/mds.22340","article-title":"Movement Disorder Society-sponsored revision of the Unified Parkinson\u2019s Disease Rating Scale (MDS-UPDRS): Scale presentation and clinimetric testing results","volume":"23","author":"Goetz","year":"2008","journal-title":"Mov. Disord."},{"key":"ref_34","unstructured":"(GraphPad Prism, 2023). GraphPad Prism, version 10."},{"key":"ref_35","unstructured":"(2024). IBM SPSS Statistics Version 30.0.0.0, IBM Corp."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1016\/B978-0-12-821377-3.00018-0","article-title":"Retinal ganglion cells and the magnocellular, parvocellular, and koniocellular subcortical visual pathways from the eye to the brain","volume":"178","author":"Solomon","year":"2021","journal-title":"Handb. Clin. Neurol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"893","DOI":"10.1002\/ana.25897","article-title":"Dopaminergic Retinal Cell Loss and Visual Dysfunction in Parkinson Disease","volume":"88","author":"Lax","year":"2020","journal-title":"Ann. Neurol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"507","DOI":"10.1038\/eye.2013.4","article-title":"Use of Fourier-domain OCT to detect retinal nerve fiber layer degeneration in Parkinson\u2019s disease patients","volume":"27","author":"Satue","year":"2013","journal-title":"Eye"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1314","DOI":"10.1038\/s41433-022-02112-4","article-title":"Ability of Swept-source OCT and OCT-angiography to detect neuroretinal and vasculature changes in patients with Parkinson disease and essential tremor","volume":"37","author":"Satue","year":"2023","journal-title":"Eye"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"e009658","DOI":"10.1136\/bmjopen-2015-009658","article-title":"Visual dysfunction and its correlation with retinal changes in patients with Parkinson\u2019s disease: An observational cross-sectional study","volume":"6","author":"Polo","year":"2016","journal-title":"BMJ Open"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"462","DOI":"10.1016\/j.neuroimage.2010.12.043","article-title":"Patterns of cortical thickness and surface area in early Parkinson\u2019s disease","volume":"55","author":"Jubault","year":"2011","journal-title":"NeuroImage"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1590","DOI":"10.1002\/mds.23101","article-title":"Abnormal visual activation in Parkinson\u2019s disease patients","volume":"25","author":"Cardoso","year":"2010","journal-title":"Mov. Disord."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"E017","DOI":"10.1017\/S095252382100016X","article-title":"Superior colliculus projections to target populations in the supraoculomotor area of the macaque monkey","volume":"38","author":"May","year":"2021","journal-title":"Vis. Neurosci."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1097\/WNR.0b013e32835edbc5","article-title":"Stereopsis and extrastriate cortical atrophy in Parkinson\u2019s disease: A voxel-based morphometric study","volume":"24","author":"Koh","year":"2013","journal-title":"Neuroreport"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Ba, F., Sang, T.T., He, W., Fatehi, J., Mostofi, E., and Zheng, B. (2022). Stereopsis and Eye Movement Abnormalities in Parkinson\u2019s Disease and Their Clinical Implications. Front. Aging Neurosci., 14.","DOI":"10.3389\/fnagi.2022.783773"}],"container-title":["Brain Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-3425\/16\/2\/213\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T05:13:14Z","timestamp":1770959594000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-3425\/16\/2\/213"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,11]]},"references-count":45,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["brainsci16020213"],"URL":"https:\/\/doi.org\/10.3390\/brainsci16020213","relation":{},"ISSN":["2076-3425"],"issn-type":[{"value":"2076-3425","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,11]]}}}