Assessment of a Super Acuity Test Chart for Hyperopia Screening.

Purpose: To assess the repeatability of a prototype super acuity test chart for measuring visual acuity at 12.5 cm, and its ability to detect hyperopia in adolescents and young adults. Methods: Repeatability was estimated as within-subject standard deviation of three repeated super acuity measurements performed in 41 university students (19-26 years). Associations between super acuity and cycloplegic refractive errors, ocular biometry, distance visual acuity, accommodation, age, and sex were assessed in 119 high school students (16-18 years) using linear mixed-effects models. ROC curves and Youden index were used to estimate the best super acuity thresholds to detect rest hyperopia. Results: Mean super acuities in the university and high school cohorts were 0.14 {+/-} 0.13 and 0.12 {+/-} 0.11 logMAR, respectively. Repeatability was 0.031. Super acuity was poorer in those with uncorrected hyperopia [spherical equivalent refractive error (SER) [&ge;] 1.00 D] than the others [SER < 1.00 D; P = 0.039]. There were significant associations between poorer super acuity and more positive ametropia (SER; P = 0.026), poorer accommodation amplitude (P < 0.001), shorter axial length (P = 0.013), male sex (P < 0.001), and age (P = 0.037). Sensitivity and specificity for detecting hyperopia (SER [&ge;] 1.00 D) were 63.2% and 64.2%, respectively, at a super acuity threshold of 0.09 logMAR. Discussion: The super acuity prototype shows promise as a screening indicator for hyperopia. Further studies are needed to optimize the test and testing protocol, and to assess its ability to detect uncorrected hyperopia in children.