Concordance between Two Subjective Techniques Used to Determine Refraction in Young Adults

Abstract

Subjective refraction is a technique whereby one lens is compared to another in order to find alens combination that results in maximum visual acuity. Studies have evaluated intraobserver orinterobserver concordance, along with other objective or subjective techniques, mostly for theJackson Cross Cylinder (JCC), but few for fogging and use of astigmatic dials (EmD, for its initialsin Spanish). <em><strong>Objective</strong><em> To determine the reproducibility of subjective methodsEmD and JCC, aswell as their concordance with the objective procedureof static retinoscopy. <em><strong>Methodology</strong><em> A descriptiveconcordance study was carried out among 190individuals, with independent measurementfor each technique by two evaluators. Fourier transformation was used on statistical analysis ofrefractions. <em><strong>Results</strong><em> EmD showed a higher reproducibility for the spherical and cylindrical power,but the JCC methodology was better for the axis. Between the objective and subjective methodologies, concordance level was lower in the spherical equivalent (component M), and for the JCCwe can see that accuracy and precision are poor, pointing out that measurements made mostlyin the spherical component are different on average and in technique repetition. <em><strong>Conclusions</strong><em> Discrepancies between evaluators or procedures in the cylinder may be of up to ±0.50 D and 10°at the axis, but it can go up to 1.00 D in the sphere; both techniques are valid for the evaluationof subjective refraction in young individuals.