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SCIENTIFIC LITERATURE · MED

Contrast Sensitivity Function in Parkinson's Disease: Effects of Illumination and Disease Stage.

Ophthalmic Physiol Opt · 2026-04-27

DOI: 10.1007/s44402-026-00091-7PMID: 42043759

Open accessresearch-article; Journal ArticleOriginal source ↗

Research overview

The text below is the source article’s original abstract under a verified reuse license. cc by

PurposeContrast sensitivity function (CSF) is a valuable tool for assessing visual function, which can be affected in neurodegenerative disorders such as Parkinson's Disease (PD). Visual perception in everyday life depends on the ability to detect objects across a wide range of spatial frequencies under different illumination conditions. However, the effect of disease progression and varying illumination on CSF in individuals with PD remains underexplored. The aim of this study was to investigate CSF in PD participants across six illumination conditions, examining disease stage influence and comparing results with age-matched healthy controls.MethodsCSF was measured with the Functional Acuity Contrast Test. This prospective, comparative study evaluated CSF under photopic, mesopic and glare conditions, across disease stages, classified according to the Hoehn and Yahr Scale. The index of contrast sensitivity (ICS) assessed overall CSF.ResultsSeventy-one PD participants and 97 healthy controls were included. PD participants demonstrated significantly poorer CSF than controls across photopic, mesopic and glare conditions (mixed-model analysis, p ConclusionsThis is the first study to assess CSF comprehensively with ICS data under six illumination conditions in PD, considering disease stage and comparing with controls. PD participants experience significant visual deficits, particularly under mesopic and glare conditions. While contrast impairments are robust in PD, stage-related differences appear partially influenced by age. These findings highlight the clinical importance of evaluating CSF under ecologically relevant lighting environments to better characterise functional visual impairment in PD and its impact on activities of daily living.

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