Assessment of a Super Acuity Test Chart for Hyperopia Screening.

PurposeTo 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. MethodsRepeatability 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. ResultsMean 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. DiscussionThe 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.