Analysis of refraction error of cataract with extreme high myopia after phacoemulsification

Abstract

Objective To investigate the affecting factors of refraction error in cataract with extreme axial myopia after phacoemulsification. Methods The data of 61 eyes of 50 cases of cataract with axial length >30 mm extreme high axial myopia from Jan. 2017 to Dec. 2017 who received phacoemulsification were retrospectively analyzed. Postoperative refractions were measured and compared with predictive refractions. The mean absolute refractive error(MAE)was calculated. Results The follow-up time was 2-6 months, with average of (3.14±0.95) months. The target spherical equivalent was (-2.82±1.02) D, postoperative spherical equivalent was (-2.14±1.30) D, the difference was significant between target and postoperative spherical equivalent(t=-6.350, P=0.000). MAE was (0.88±0.52) D. There was positive correlation between MAE and axial length(r=0.549, P=0.000). The refraction errors was within ±1.0 D of target spherical equivalent in 42 eyes(68.9%), however, only 10 eyes(43.5%)of minus-IOL showed a prediction error within ±1.0 D. Compared with plus-IOL and zero-IOL, MAE of minus-IOL was higher, the difference was statistically significant(P=0.000). Conclusion Refraction errors are increasing with axial length, which are more pronounced with minus-IOL. Key words: Myopia, extreme high; Cataract; Refractive error; Lens, intraocular, minus