Accuracy and repeatability of refractive error measurements by photorefractometry

Abstract

Purpose:To determine the accuracy of photorefraction and autorefraction as compared to cycloautorefraction and to detect the repeatability of photorefraction.Methods:This diagnostic study included the right eyes of 86 children aged 7-12 years. Refractive status was measured using photorefraction (PlusoptiX SO4, GmbH, Nürnberg, Germany) and autorefraction (Topcon RM800, USA) with and without cycloplegia. Photorefraction for each eye was performed three times to assess repeatability.Results:The overall agreement between photorefraction and cycloautorefraction was over 81% for all refractive errors. Photorefractometry had acceptable sensitivity and specificity for myopia and astigmatism. There was no statistically significant difference considering myopia and astigmatism in all comparisons, while the difference was significant for hyperopia using both amblyogenic (P = 0.006) and nonamblyogenic criteria (P = 0.001). A myopic shift of 1.21 diopter (D) and 1.58 D occurred with photorefraction in nonamblyogenic and amblyogenic hyperopia, respectively. Using revised cut-off points of + 1.12 D and + 2.6 D instead of + 2.00 D and + 3.50 D improved the sensitivity of photorefractometry to 84.62% and 69.23%, respectively. The repeatability of photorefraction for measurement of myopia, astigmatism and hyperopia was acceptable (intra-cluster correlation [ICC]: 0.98, 0.94 and 0.77, respectively). Autorefraction results were significantly different from cycloautorefraction in hyperopia (P < 0.0001), but comparable in myopia and astigmatism. Also, noncycloglegic autorefraction results were similar to photorefraction in this study.Conclusion:Although photorefraction was accurate for measurement of myopia and astigmatism, its sensitivity for hyperopia was low which could be improved by considering revised cut-off points. Considering cut-off points, photorefraction can be used as a screening method.

Performance of Plusoptix A09 Photo Screener in Refractive Error Screening in School Children Aged between 5 and 15 Years in the Southern Part of India

“…Regarding the cylindrical results, studies agree with the consistency of the cylindrical power between the Plusoptix and cycloretinoscopy. 34 A similar phenomenon was observed here with 0.50 DC higher results in comparison to retinoscopy.…”

“…One of the studies had modified the referral criteria for hypermetropia (+1.12 D and +2.60 D instead of +2.00 D and +3.50 D) to get a revised sensitivity value (65.38% to 84.62% and from 46.15% to 69.23%). 34 Few studies have reported the underestimation of refractive error and having higher accuracy in myopia than hyperopia in the pediatric population. 34 35 In this study, an overall hyperopic shift in the values was observed in comparison to retinoscopy.…”

“… 34 Few studies have reported the underestimation of refractive error and having higher accuracy in myopia than hyperopia in the pediatric population. 34 35 In this study, an overall hyperopic shift in the values was observed in comparison to retinoscopy. As per AAPOS, ≥+0.50 DS was considered hyperopic.…”

Pediatric vision screening using the plusoptiX A12C photoscreener in Chinese preschool children aged 3 to 4 years

“…During further analysis, the spherical values agreed well with the emmetropia group ( P = 0.33) compared with the hyperopia group ( P < 0.0001). Regarding the cylindrical results, several researchers agreed with the consistency of the cylindrical power between the device and CR 13 , 15 , whereas others did not 16 , 17 . In the present study, the plusoptiX overestimated the the cylindrical power in all groups, thus resulting in the partial or total underestimation of SE (all P < 0.0001).…”

“…The plusoptiX has been reported by the majority of studies to underestimate children’s refractive error and to have higher accuracy in myopic children than hyperopic children 13 – 15 . In the present study, the plusoptiX A12C led to a considerable shift towards myopic values (0.45 D), particularly in the hyperopia group (1.62 D), because of normal accommodation.…”