Classification of accommodative insufficiency by monocular subjective push-up test is poorly predictive of monocular objective amplitudes in children and young adults.

Abstract

Introduction: To determine whether classification of accommodative insufficiency (AI) based on the subjective push-up test is indicative of reduced amplitude measured objectively.

Methods: Monocular subjective accommodative amplitude was measured in participants 7-24 years of age with the push-up test; a 0.9 mm letter was moved towards the eye until first sustained blur occurred. Monocular objective amplitude was measured with the same target and an autorefractor for demands from 2.5 to 30 D. The maximum response was termed the amplitude. Near point of convergence (NPC) was measured in a subset of participants. Participants were classified into groups using subjective amplitude: normal amplitude or AI (amplitude < ((15 - 0.25 × age) - 2)). Objective amplitude was plotted by age for each group and one-way ANCOVA used to evaluate differences while controlling for age. For NPC measures, a t-test compared the magnitude of the break between those with and without AI.

Results: Fifty-five of 185 participants were classified as having AI. Objective amplitude decreased with age (0.20 D/year) and there was no significant difference in the age-adjusted mean amplitudes for the two groups (AI: 7.62 D, CI = 7.19, 8.04; Normal: 7.86 D, CI = 7.58, 8.15; p = 0.11). For the subset with NPC measures, participants classified as having AI had significantly more receded break values than those without AI (7.7 ± 5 vs. 3.7 ± 3 cm, p < 0.001).

Conclusions: Factors other than accommodative ability may be contributing to lower subjective amplitude findings in individuals meeting the criterion for AI.