Contrast letter acuity as a measure of visual dysfunction in patients with Friedreich ataxia.

Abstract

BACKGROUND:

Friedreich ataxia is a progressive neurodegenerative disorder affecting afferent cerebellar pathways and other neuronal systems, including afferent visual pathways. A systematic clinical outcome measure for examination of visual dysfunction in Friedreich ataxia has not been identified. We sought to identify a simple, reliable method for assessing clinical and subclinical visual dysfunction in patients with Friedreich ataxia.

METHODS:

Contrast letter acuity was measured binocularly in Friedreich ataxia patients and age-matched visually asymptomatic volunteers (control group) using the Low-contrast Sloan Letter Charts at three different low-contrast levels (5.0%, 1.25%, and 0.6%). Binocular high-contrast visual acuity (100% level) was also determined for each participant.

RESULTS:

Despite equal median binocular high-contrast visual acuities between the two groups, patients with Friedreich ataxia had significantly lower (worse) Low-contrast Sloan Letter Chart scores compared with controls, particularly at the lowest contrast levels (1.25% and 0.6%). Ambulation status significantly predicted Low-contrast Sloan Letter Charts scores in linear regression models accounting for patient age, suggesting a potential complementary role for Low-contrast Sloan Letter Chart testing in the assessment of disease status as well as visual function in Friedreich ataxia.

CONCLUSIONS:

This study demonstrates that Low-contrast Sloan Letter Chart testing may provide a useful clinical outcome measure for Friedreich ataxia and other neuro-ophthalmologic disorders.

• Authors: David R Lynch, Jennifer M Farmer, Dustin Rochestie, Laura J Balcer
• Journal: Journal of neuro-ophthalmology : the official journal of the North American Neuro-Ophthalmology Society (J Neuroophthalmol) Vol. 22 Issue 4 Pg. 270-4 (Dec 2002) ISSN: 1070-8022 [Print] United States
• PMID: 12464730 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Topics

• Adolescent
• Adult
• Child
• Contrast Sensitivity
• Friedreich Ataxia (complications)
• Humans
• Middle Aged
• Vision Disorders (diagnosis, etiology)
• Vision Tests
• Vision, Binocular
• Visual Acuity