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.
Keywords: Hyperopia; Iris barycenter; Kappa angle; Myopia; Pupil barycenter.
© 2022. The Author(s), under exclusive licence to Springer Nature B.V.