System for Objective Assessment of the Accommodation Response During Subjective Refraction

PURPOSE: To evaluate a system based on a Hartmann–Shack wavefront sensor attached to a phoropter that allows the user to obtain real-time information about the refractive state of the eye and the accommodation response (AR). METHODS: The objective refractions (M(E)) and ARs of 73 subjects (50 women, 23 men; ages, 19–69 years) were assessed with the system developed while placing in the phoropter the subjective refraction (M(S)) plus a set of trial lenses with differences in spherical equivalent power (ΔM) between ±2 diopters (D). RESULTS: The objective estimations (M(E)) showed a good correlation with the subjective values (M(S)) (r = 0.989; P < 0.001). The means of the ARs presented a region where the accommodation remained stable (ΔM from +2 D to about 0 D), followed by another in which the response increased progressively (ΔM from about 0 to −2 D) with the magnitude of the accommodation stimulus. The analysis of variance within subjects applied to ARs introducing age and M(S) as covariates showed an increasing effect size of age from medium to large between ΔM of −0.5 and −2 D. In contrast, M(S) had a medium effect size (between ΔM of +2 and 0 D). CONCLUSIONS: The implemented system permitted an objective estimation of the refraction of the eye and its AR. Because it is coupled to a phoropter, the system can be used to retrieve the AR during subjective refraction procedures. TRANSLATIONAL RELEVANCE: The developed system can be used as a supporting tool during subjective refraction to provide certainty about the true state of accommodation.