Visual Function in Patients with Amyotrophic Lateral Sclerosis

Abstract

 

Purpose

 

Amyotrophic Lateral Sclerosis is the most common form of progressive motor neuron disease with an incidence in most societies of 1-3 per 100,000. Approximately 90% of cases are due to sporadic mutations (Sporadic ALS) while 10% are due to an inherited genetic trait (Familial ALS). ALS is a neurodegenerative disease of both upper and lower motor neurons that is classically thought of as sparing sensory and autonomic pathways that are necessary for visual function. However, ophthalmoparesis has been reported, particularly in patients with prolonged survival, as well as retinal pathology in the anterior visual pathway in an ALS genetic variant (ALS5 [SPG11]). In order to better characterize visual function in these patients, we undertook this study to assess detailed measures of visual function in ALS patients and compare visual function among different genetic variants.

 

Methods

 

Patients with either Familial variants or Sporadic ALS were recruited from the Northwestern University Neurology Department’s Les Turner/Lois Insolia ALS Center. These patients underwent a complete ophthalmologic examination in the Ophthalmology Department. Visual assessment included refraction/best-corrected visual acuity, intraocular pressure, and a visual function questionnaire (VFQ-25). Best corrected visual acuity was converted to the LogMAR scale for statistical analysis. Color testing using the Lanthony D-15 test and Pelli-Robson contrast sensitivity were added to the visual assessment testing after the 10^th patient was enrolled. Visual function results from Sporadic and Familial ALS patients were compared using a two-sample T test.

 

Results

 

We have collected data from 23 patients with 3 different Familial variants of ALS (ALS5 [SPG11], c9orf72, CHCHD10) as well as Sporadic ALS. Sporadic ALS demographics (n=15): Gender - 73% male; Mean age - 57; Race - all Caucasian. Familial ALS demographics (n=8): Gender - 50% male; Mean age - 34; Race - 7 Caucasian, 1 Hispanic. Mean LogMAR visual acuity in Familial was .11; Mean LogMAR visual acuity in Sporadic was .016 (T test comparison, p=.07). Average VFQ-25, contrast sensitivity, and color testing were not statistically significant. Additionally, we plan to correlate these clinical values with disease severity.

 

Conclusions

 

ALS represents a wide spectrum of diseases. This ongoing study will attempt to identify visual dysfunction and correlate it to disease severity parameters among different variants of ALS.