Accuracy of Intraocular Lens Power Calculations According to the Formulas and Anterior Chamber Depth in Short Eyes

PURPOSE: To evaluate the accuracy of intraocular lens (IOL) power calculations according to the chosen formulas and anterior chamber depths in eyes with short axial lengths. METHODS: A retrospective analysis was performed on 57 eyes of 50 patients (axial length < 22.0 mm) and 42 eyes of 36 patients (22.0 mm < or = axial length < 25.0 mm) who underwent cataract surgery. IOL power was calculated with the SRK II, SRK/T, Binkhorst, Holladay I, and Hoffer Q formulas. The differences between the predicted refraction and the actual refraction were compared and analyzed. The errors according to the anterior chamber depth were also evaluated. RESULTS: The SRK II formula showed a lower predictive accuracy, and the other formulas showed similar accuracies in eyes with short axial lengths. The Holladay 1 and Hoffer Q formulas showed good predictive accuracies in eyes with short axial lengths. Hyperopic shift tended to occur with all formulas in eyes with short axial lengths. When using SRK II and SRK/T formulas, a correlation between axial length and hyperopic shift was observed, with shorter axial length patients shifting to more hyperopic conditions. In eyes with short axial lengths, larger hyperopic shifts tended to occur in eyes with relatively deeper anterior chambers. CONCLUSIONS: In eyes with short axial lengths, preoperative predicted IOL power showed good accuracies with Holladay 1 and Hoffer Q formulas. Preoperative anterior chamber depth and axial length had a strong influence on the accuracies of predicted IOL power.

Comparison of IOL Formulas in Pediatric Intraocular Lens Implantation

PURPOSE: To evaluate the refractive outcomes using 5 different IOL power calculation formulas (SRK II, Holladay I, Hoffer Q, SRK T, Binkhorst II) in pediatric cataract patients. METHODS: A retrospective analysis of biometric and refractive data was performed on 63 eyes of 44 pediatric patients, who successfully underwent primary and secondary IOL implantation. For analysis, the eyes were divided into three groups: those with axial length or =22 mm but or =24.5 (group L). And also divided into another three groups: those with mean keratomery value or =42.5D but or =44.5D (group III). The postoperative refractive outcome was taken as a spherical equivalent of the refraction at 1 week and 2 to 3 months after surgery. The 'predictive error' was defined as absolute error between the target and actual postoperative refraction. RESULTS: SRK II had a best predictive error but there was no statically significant in short eye group and medium eye group at 1 week and 2 to 3 months after the surgery. And SRK II also had a best predictive error but there was no statically significant in group I, II, and III at 1 week and 2 to 3 months. CONCLUSIONS: In our study, theoretical formulas did not outperform the regression formula in pediatric IOL implantation. This may be related to the variability of the relationship between axial length and corneal curvature in pediatric eyes and to dependent variables inherited in the formulas.