Visual Image Quality Reduced in Down Syndrome, Even With Special Lenses

Both visual acuity and visual image quality are reduced in those with Down syndrome, even while wearing optimized spectacle correction, according to a study in the journal Optometry & Vision Science. A sensory deficit in the visual system, in either the eye or retina or at the cortical level may be part of the reason along with uncorrected aberrations. Differences are seen in both retinal thickness and dendritic spines in patients with Down syndrome.

The team enrolled 30 adult patients with Down syndrome (average age, 29±10 years) to understand if an association exists between a reduction in visual acuity and visual image quality. Wavefront aberration was recorded from the patients, and a computer program was utilized to apply 20,000 refractions to the uncorrected wavefront error of each eye and calculate the optimized logVSX using the visual Strehl ratio (VSX). This measure of visual image quality is known to be correlated with visual acuity in this patient population. Both logVSX and visual acuity data were compared between the patients with Down syndrome and values for a typical population. 

The report finds optimized logVSX values were significantly poorer for those with Down syndrome (average: −0.56±0.19) compared with the minimum (average: −0.47±0.12) or mean (average: −0.26±0.10) values predicted in the normal population.

Furthermore, their visual acuity was also reduced and there was a significant relationship between visual acuity and optimized logVSX (P =.03), though modest correlation, suggesting that other factors may also contribute to the reduction in visual acuity.

Even with the best spectacle correction, patients with Down syndrome have uncorrected aberrations.

“These residual aberrations may account for some of the reduction in best-corrected visual acuity, although neural deficits cannot be ruled out,” according to the researchers.

They suggest that treatment with rigid contact lenses may reduced high order aberrations, but may only work in a portion of those with Down syndrome and adaptations to the lens comfort and insertion and removal process may be difficult.

This article originally appeared on Optometry Advisor