New Insights Into Vision Problems in Parkinson's

Damian McNamara

March 12, 2020

Visual problems are significantly more common in patients with Parkinson disease (PD) and adversely affect quality of life by interfering with normal daily activities, new research suggests.

In a study with more than 1000 participants, more than 82% of the patients with PD had at least one ophthalmologic symptom, in comparison with 48% of matched control persons who did not have the disease. Symptoms included double vision, blurriness, and watery eyes.

In addition, 52% of respondents with PD reported that their eye symptoms restricted reading; 33% reported that their symptoms had a negative effect on driving; and 28% experienced more difficulty watching television or working on a computer.

"Our findings emphasize a great need for a much better awareness of the debilitating ocular disorders that are commonly present in patients with Parkinson's disease. This greater awareness is needed for physicians, patients, and caregivers," lead author Carlijn D. J. M. Borm, a neurology resident at the Center for Expertise for Parkinson and Movement Disorders, Radboud University Medical Center, Nijmegen, the Netherlands, told Medscape Medical News.

The results "add new knowledge about the prevalence of a wide range of ocular symptoms and, importantly, on the effect of these symptoms on daily life functioning," she noted.

The findings were published online March 11 in Neurology.

Underreported, Overlooked

The study builds on previous basic-science research suggesting that PD can cause symptoms related to changes in the eyes or eyelids, including visual perception.

"Unfortunately, these basic findings never translated well into daily clinical practice, where ophthalmologic symptoms are underreported and often overlooked," Borm said.

"This is particularly unfortunate for patients with Parkinson's disease because they typically have problems with internally guided movements and postural control, which they can compensate for by guiding their movements visually," she added.

"Little is known about the extent and frequency of ophthalmologic symptoms and their effect on daily life activities in patients with PD. As almost 80% of visual impairments worldwide are treatable or preventable, timely recognition is pivotal," the researchers write.

To learn more, the investigators conducted a multicenter, cross-sectional study of 1098 participants (mean age, 70 years) in Austria and the Netherlands who completed the Visual Impairment in Parkinson's Disease Questionnaire (VIPD-Q).

Of these, 848 had PD (60% men); 250 acted as age-matched control participants (52% men). All completed the survey via mail, online, or in person between December 2016 and July 2018.

The customized VIPD-Q contains questions that address four domains related to ocular structure: the ocular surface, the intraocular area, oculomotor function, and the optic nerve. One additional question addresses visual hallucinations.

The researchers also asked whether participants' ophthalmologic symptoms affected their quality of life.

Screening, Treatment Implications

All ophthalmologic symptoms were significantly more prevalent in the patient group than in the control group, the researchers note.

More than 82% of the patients with PD had at least one ophthalmologic symptom, compared with 48% of the healthy control group (P < .001).

Seeing colors less brightly, having double vision, having difficulty with depth perception, and experiencing visual hallucinations occurred almost exclusively in the PD group. The prevalence of visual hallucinations, for example, was 22% in the PD group, compared with only 2% among the control group (P < .001). Both study groups reported having watery eyes, experiencing sensitivity to light, and seeing glare at night.

A significantly greater proportion of the PD cohort reported that their ophthalmologic symptoms had a "moderate" or "severe" effect on their quality of life (53%; 95% confidence interval [CI], 49% – 56%), compared with 16% of the control group (95% CI,12% – 21%; P < .001).

The investigators recognized that visual impairment could affect fall risk in this population. Patients with PD fell more frequently on a daily or weekly basis (4% vs 0%) and more frequently fell once or twice per month (28% vs 12%; both comparisons, P < .001).

Borm said she is hopeful the findings will increase awareness and promote timelier recognition of these common visual symptoms in PD.

"Our findings should motivate clinicians to proactively seek these visual disturbances, as many are potentially treatable. This can help to contribute to greater independence, a better quality of life, and possibly a reduction of falls and fractures," she said.

Routine screening may also be warranted, Borm added.

The VIPD-Q could help identify ophthalmologic symptoms "that might otherwise be missed, thereby enabling timely referral and treatment," the researchers write. However, "further work is needed to optimize the present VIPD-Q for such use in screening."

The investigators have recruited 106 patients with PD from this phase 1 study cohort for in-depth neurologic and ophthalmologic assessment. This second phase of the study will evaluate the prevalence of ocular disorders, assess the severity and clinical impact of different ocular disorders on daily life function, and evaluate fall risk.

Important Reminder

Asked to comment on the study for Medscape Medical News, Deborah Hall, MD, PhD, director of the Movement Disorders Program and the Parkinson's Foundation Chair of Neurological Sciences at Rush University Medical Center, Chicago, Illinois, said her "overall impression" is that the study reminds both neurologists and patients that eye symptoms are attributable to PD.

"Many patients may not know that the disease is associated with eye abnormalities, and busy clinicians may not be asking questions regarding eye symptoms in their practices," said Hall, who was not involved with the research.

"This study also highlights the high prevalence of ophthalmologic symptoms and that they interfere with activities of daily living," she added.

The study was funded by a research grant from the Stichting Parkinson Fonds. Borm has disclosed no relevant financial relationships. Hall has received research support from AbbVie, Biogen, Biohaven, Fujifilm, and Neurocrine.

Neurology. Published online March 11, 2020. Abstract

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