Spectacles for Patients With Down Syndrome

This study tests the hypothesis that objectively derived spectacle prescriptions based on wavefront aberration measurements of the eyes of individuals with Down syndrome can provide an improvement in visual acuity over that obtained with spectacle prescriptions based on standard clinical prescribing techniques. The objectively derived prescriptions are derived using strategies to optimize retinal image quality as measured by image quality metrics, and thus these prescriptions will be referred to as metric-derived.

Individuals with Down syndrome suffer from significant ocular complications including high levels of lower-order refractive error (sphere and cylinder) and elevated levels of higher-order aberrations. These optical factors likely contribute to the poor acuity observed in this population. Current clinical prescribing practices may under-serve this community, as the cognitive demands of the subjective refraction sequence are difficult for this population and often leave clinicians to prescribe from objective clinical findings that target full correction of sphero-cylindrical refractive error. This prescribing practice can lead to sub-par outcomes given the fact that full lower-order corrections can exacerbate the effects of higher-order aberrations in more aberrated eyes. For this study, individuals with Down syndrome will be dispensed three pairs of spectacles for 2 months each, in random order: one clinically-derived, and two objectively-derived refractions based upon methods designed to optimize a given metric of retinal image quality which takes into consideration the wavefront aberration measurements of the eye. Both initial and adapted visual acuity in the presence of each correction will be evaluated to determine whether the objectively-derived refractions outperform clinically-derived refractions.

Each subject will receive all three spectacle prescription interventions dispensed in randomized order for 2 months of wear each. Subjects in this arm of the study will receive the clinically derived prescription first, followed by the metric-derived #1, and lastly the metric-derived #2.

Each subject will receive all three spectacle prescription interventions dispensed in randomized order for 2 months of wear each. Subjects in this arm of the study will receive the clinically derived prescription first, followed by the metric-derived #2, and lastly the metric-derived #1.

Each subject will receive all three spectacle prescription interventions dispensed in randomized order for 2 months of wear each. Subjects in this arm of the study will receive the metric-derived #1 prescription first, followed by the clinically derived prescription, and lastly the metric-derived #2 prescription.

Each subject will receive all three spectacle prescription interventions dispensed in randomized order for 2 months of wear each. Subjects in this arm of the study will receive the metric-derived #2 prescription first, followed by the clinically derived prescription, and lastly the metric-derived #1 prescription.

Each subject will receive all three spectacle prescription interventions dispensed in randomized order for 2 months of wear each. Subjects in this arm of the study will receive the metric-derived #1 prescription first, followed by the metric-derived #2 prescription, and lastly the clinically derived prescription.

Each subject will receive all three spectacle prescription interventions dispensed in randomized order for 2 months of wear each. Subjects in this arm of the study will receive the metric-derived #2 prescription first, followed by the metric-derived #1 prescription, and lastly the clinically derived prescription.

Prescription spectacle lenses determined by clinically derived techniques. The specific techniques employed for each subject are left up to the masked examiner and are dependent upon the information needed for refraction determination, as well as ability of the participant to cooperate for testing. Measures may include autorefraction obtained pre or post dilation, retinoscopy obtained pre or post dilation, and subjective refraction obtained pre or post dilation.

Prescription spectacle lenses determined by metric-derived objective technique #1. For this method, wavefront error will be measured with the COAS (complete ophthalmic analysis system) wavefront aberrometer post-dilation with the goal of obtaining 3 to 5 high quality captures per eye. Wavefront measures will be re-sized to the patient's habitual pupil diameter and averaged. Post-measurement analysis will then be performed using a computer algorithm to identify the refractive correction predicted to produce the best image quality, as measured by maximization of the image quality metric Visual Strehl ratio in the spatial domain (VSX). The refractive correction determined from this analysis will be produced in prescription spectacle lenses and dispensed to the patient as the Intervention: Spectacles - Metric Technique #1 Derived.

Prescription spectacle lenses determined by metric-derived objective technique #2. For this method, wavefront error will be measured with the COAS (complete ophthalmic analysis system) wavefront aberrometer post-dilation with the goal of obtaining 3 to 5 high quality captures per eye. Wavefront measures will be re-sized to the patient's habitual pupil diameter and averaged. Post-measurement analysis will then be performed using a computer algorithm to identify the refractive correction predicted to produce the best image quality, as measured by maximization of the image quality metric Pupil Fraction tessellated (PFSt). The refractive correction determined from this analysis will be produced in prescription spectacle lenses and dispensed to the patient as the Intervention: Spectacles - Metric Technique #2 Derived.

Aided LogMAR distance visual acuity obtained with either the British Standard Letters or HOTV - matching for subjects unable to name letters.

Aided LogMAR distance visual acuity obtained with either the British Standard Letters or HOTV - matching for subjects unable to name letters.

Total wear time of each pair of spectacles as measured objectively by a temperature sensor data logger mounted to the spectacle temple.

Participants were asked to select a face from a survey with five expressions (large frown, small frown, neutral, small smile, large smile) depicting their response to the question 'Do you like wearing this pair of glasses?' Responses were coded 1 through 5 with 5 = large smile.

Participants were asked to select a face from a survey with five expressions (large frown, small frown, neutral, small smile, large smile) depicting their response to the question 'How well do you see with this pair of glasses when looking far away?' Responses were coded 1 through 5 with 5 = large smile.

Participants were asked to select a face from a survey with five expressions (large frown, small frown, neutral, small smile, large smile) depicting their response to the question 'How well do you see with this pair of glasses when looking up close?' Responses were coded 1 through 5 with 5 = large smile.

Inclusion Criteria: Diagnosis of Down syndrome Exclusion Criteria: Nystagmus (Involuntary beating movement of the eyes) Visually significant media opacities (e.g. cataracts or corneal scars) Strabismic amblyopia (reduced vision in one eye related to a constant eye-turn) Anisometropic amblyopia (reduced vision in one eye related to a long-standing uncompensated difference in prescription between the two eyes)

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 Jan 1;99(1):58-66. doi: 10.1097/OPX.0000000000001834.

Anderson HA, Benoit JS, Marsack JD, Manny RE, Ravikumar A, Fern KD, Trast KR. A Randomized Trial of Objective Spectacle Prescriptions for Adults with Down Syndrome: Baseline Data and Methods. Optom Vis Sci. 2021 Jan 1;98(1):88-99. doi: 10.1097/OPX.0000000000001631.