Visual acuity and contrast sensitivity in multiple sclerosis--hidden visual loss: an auxiliary diagnostic test

Area of Science:

• Neuroscience
• Ophthalmology
• Clinical Neurology

Background:

• Conventional clinical tests for visual acuity in multiple sclerosis (MS) primarily focus on fine detail.
• These tests may fail to detect subtle visual defects affecting everyday life and perception.
• There is a need for more sensitive methods to identify early-stage visual impairments in MS.

Purpose of the Study:

• To evaluate the utility of sine-wave gratings in assessing visual sensitivity for varying detail levels (coarse, medium, fine) in patients with multiple sclerosis.
• To compare the diagnostic capability of this novel test against conventional methods like the Snellen test.
• To identify specific patterns of visual defects indicative of neural origin in MS.

Main Methods:

• A cohort of 48 patients diagnosed with multiple sclerosis underwent visual sensitivity testing using sine-wave gratings.
• The test assessed sensitivity to coarse, medium, and fine visual details, unlike traditional visual acuity measurements.
• Results were analyzed to identify visual defects not detectable by the standard Snellen test.

Main Results:

• A significant visual defect of neural origin was identified in 20 out of 48 patients.
• In 11 patients, sensitivity to medium detail was markedly reduced, while coarse and fine detail sensitivity remained intact.
• Three patients exhibited selective degradation of sensitivity to coarse detail, with no clinical evidence of visual involvement in 8 of these cases.

Conclusions:

• Sine-wave grating testing reveals visual defects in multiple sclerosis patients that are undetectable by conventional acuity tests.
• These defects, particularly those affecting medium and coarse detail sensitivity, can lead to significant visual problems and distorted perception.
• This test shows promise for earlier diagnosis of multiple sclerosis and understanding its impact on visual function.