Pupil barycenter configuration in patients with myopia and hyperopia

Abstract

Purpose To compare the apparent chord mu between hyperopia and myopia cases and investigate the usefulness of iris barycenter configurations as an alternative for performing kappa angle distance calculations. Methods This prospective study evaluated 394 eyes of 197 patients classified into two groups according to their spherical equivalent values: the myopic (mean spherical equivalent refraction <= - 0.50 D) and the hyperopia group (mean spherical equivalent refraction >= + 0.50 D). The two groups were further subdivided according to severity (myopic group: mild, <= - 0.50 and <= - 3.00 D; moderate, < - 3.00 and <= - 6.00 D; severe, < - 6.00 D; hyperopic group: mild, >= + 0.50 and <= + 2.00 D; moderate, > + 2.00 and <= + 4.00 D; severe, > + 4.00 D). The pupil and iris barycenter distance measurements and other parameters were obtained through optical low-coherence reflectometry. Results Of the 197 patients, 109 (55.3%) were female and 88 (44.7%) were male individuals; their ages ranged from 7 to 60 years (mean, 35.16 +/- 14.75 years). The average pupil barycenter distances were 0.38 +/- 0.15 and 0.21 +/- 0.11 mm in hyperopia and myopia patients, respectively (p < 0.01). Corneal and lens thickness measurements were higher in hyperopia patients (p < 0.01, p < 0.01, respectively), whereas anterior chamber depth and pupil diameter measurements were higher in myopia patients (p < 0.01, p < 0.01, respectively). No significant difference in astigmatism or white-to-white measurements was observed between hyperopia and myopia patients (p > 0.05). Conclusion The measurements for the apparent chord mu of the pupil and iris barycenter origins were higher in hyperopic than in myopic cases.