Wavefront-Optimized Refractions Are an Option for Patients With Down Syndrome

Objective, wavefront–optimized refractions provide visual acuity correction equivalent to expert clinical refractions for adults with Down syndrome, according to research published in Optometry and Vision Science.

Researchers assessed 30 adult patients with Down syndrome (mean age 29±10 years, 21 routine spectacle wearers), provided them with a clinical refraction, and administered the Vineland Adaptive Behavior Test. Results revealed that 9 participants had strabismus, 18 had low adaptive functioning, 11 had moderately low adaptive functioning, and 1 had adequate functioning.

In addition to the clinical refraction, investigators obtained objective refractions on all participants via dilated wavefront aberration measures. They utilized each of 2 image quality metrics; a pupil fraction tessellated refraction and a visual Strehl ratio objective refraction. They dispensed all 3 refractions to the participants and instructed them to wear each one for a period of 2 months. Patients were randomly assigned to 1 of 6 treatment arms depending on the order in which they received their refractions.

The researchers identified a significant effect of treatment (F = 5.00, P =.01) for monocular acuity. Visual Strehl ratio refractions achieved a 0.04 logMAR improvement compared with the other 2 treatments (pupil fraction tessellated vs visual Strehl ratio t = 2.73, P =.03, visual Strehl ratio vs clinical t = -2.74, P =.02).

Estimated least square means for binocular acuity at 2 months were 0.34 (95% CI 0.25-0.39) for clinical refractions, 0.31 (95% CI 0.25 to 0.36) for pupil fraction tessellated refractions, and 0.33 (95% CI 0.27 to 0.38) for visual Strehl ratio refractions.

A total of 26 participants (87%) experienced acuity gains with at least 1 treatment, and 15 gained at least 1 line of visual acuity in a treatment. The spherical equivalent was associated with the number of hours patients wore their glasses per day.

The researchers reported patients had high satisfaction across treatment types, with no serious adverse events. Among non serious adverse events reported, 15 of the 36 were classified as “unrelated to study treatment.”

“Overall, this study demonstrates that objective, wavefront–optimized refractions provide distance visual acuity equivalent to expert clinician refractions in adults with Down syndrome with both myopic and hyperopic refractive errors,” according to the researchers. “With additional methodological development, metric-optimized refraction may be a beneficial tool in the future for practitioners who are not experienced in the examination of adults with Down syndrome or who wish to have additional refractive data to determine their prescriptions.”

Limitations of the study include how clinically derived prescriptions considered binocular vision and measurements of a range of pupil diameters, while the metric-optimized refractions considered monocular measurements with a fixed pupil diameter. 

Reference

Anderson HA, Marsack JD, Benoit JS, Manny RE, Fern KD. Visual acuity outcomes in a randomized trial of wavefront metric-optimized refractions in adults with Down syndrome. Optom Vis Sci. 2022;99(1):58-66. doi:10.1097/OPX.0000000000001834