Abnormal Visual Contrast Acuity in Parkinson's Disease

Abstract

Background: Low-contrast vision is thought to be reduced in Parkinson's disease (PD). This may have a direct impact on quality of life such as driving, using tools, finding objects, and mobility in low-light condition. Low-contrast letter acuity testing has been successful in assessing low-contrast vision in multiple sclerosis. We report the use of a new iPad application to measure low-contrast acuity in patients with PD. Objective: To evaluate low-and high-contrast letter acuity in PD patients and controls using a variable contrast acuity eye chart developed for the Apple iPad. Methods: Thirty-two PD and 71 control subjects were studied. Subjects viewed the Variable Contrast Acuity Chart on an iPad with both eyes open at two distances (40 cm and 2 m) and at high contrast (black and white visual acuity) and 2.5% low contrast. Acuity scores for the two groups were compared. Results: PD patients had significantly lower scores (indicating worse vision) for 2.5% low contrast at both distances and for high contrast at 2 m (p < 0.003) compared to controls. No significant difference was found between the two groups for high contrast at 40 cm (p = 0.12). Conclusions: Parkinson's disease patients have reduced low and high contrast acuity compared to controls. An iPad app, as used in this study, could serve as a quick screening tool to complement more formal testing of patients with PD and other neurologic disorders.

Validity of low-contrast letter acuity as a visual performance outcome measure for multiple sclerosis

“…In a recent study, it was shown that patients with Parkinson’s disease had worse LCLA compared to controls using a digitized contrast letter acuity chart displayed on an iPad. 96 This supports that an electronic version of LCLA may be useful for screening patients with neurological disease, but further research is necessary to establish the validity of this technique.…”

Introducing a new method to assess vision: Computer-adaptive contrast-sensitivity testing predicts visual functioning better than charts in multiple sclerosis patients

“…1,3 Apart from the link to real-life visual functioning, LCVA might even serve as an outcome for brain network integrity as LCVA has been, for example, linked to retinal nerve fiber thinning and cognitive performance in MS or disability in Parkinson’s disease. 10,19,20 Considering that CSF correlates with functional MRI (fMRI) activation and fMRI changes are associated with short-term adaption to contrast vision, 21,22 MRI as well as OCT might help to clarify the association of AULCSF with structural and functional integrity of visual tracts and cortex. Owing to the cross-sectional design of our study, the sensitivity to changes in MS cannot be answered yet.…”

Contrast Acuity With Different Colors in Parkinson's Disease

“…2 Previous studies have shown impaired contrast sensitivity in PD patients. 3,4 This is one of the reasons that some PD patients complain of poor vision despite a normal visual acuity. 2 Previous studies of contrast sensitivity used sine-wave gratings, which lacks reliability, particularly problematic for longitudinal studies.…”

“…2 An iPad app was previously used to assess vision contrast acuity. 3 That iPad app has now been modified to compare contrast acuity for five different colors (black, blue, yellow, red, and blue) on a white background and was studied in PD and control subjects.…”

“…Direct sunlight was not allowed in the examination room, and the background illumination (white) was set at maximum as previously published. 3 The examination was performed with the fluorescent exam room lights on. The iPad application is backlit and does not require any special lighting during testing.…”