The Clinical Efficacy of the Haigis Formula Using A-Scan Contact Ultrasound Biometry

PURPOSE: To investigate the accuracy of the Haigis formula compared to other formulas using contact ultrasound biometry. METHODS: This study was performed on 94 patients (114 eyes) who underwent cataract surgery in our hospital. Axial length (AXL) and anterior chamber depth (ACD) were measured using both A-scan and intraocular lens (IOL) Master(R). Patients were divided into three groups based on AXL; Group I (AXL or = 25.5 mm). Before cataract surgery, predicted refraction was calculated using the Haigis, SRK/T, Hoffer Q, and Holladay 1 formulas using both A-scan and IOL Master(R) measurements. Mean absolute error (MAE) were analyzed at one month after surgery using the various IOL formulas. RESULTS: Using contact ultrasound biometry, in Group I, MAE of Haigis was 0.80 +/- 0.67 D and was significantly lower than that using SRK/T. In Group II, the Haigis MAE was 0.72 +/- 0.55 D and was significantly lower than the results of all other formulas. In Group III, the Haigis MAE was 0.76 +/- 1.13 D and not significantly different from the results of other formulas. Comparing MAE of A-scan to IOL Master(R), the Haigis formula showed 0.16 D higher error that decreased when the AXL was close to the normal range. CONCLUSIONS: Using contact ultrasound biometry, the Haigis formula provided the best predictability of postoperative refractive outcome compared to other formulas in eyes with normal axial length.

The Clinical Efficacy of the Haigis Formula Using A-Scan Contact Ultrasound Biometry

PURPOSE: To investigate the accuracy of the Haigis formula compared to other formulas using contact ultrasound biometry. METHODS: This study was performed on 94 patients (114 eyes) who underwent cataract surgery in our hospital. Axial length (AXL) and anterior chamber depth (ACD) were measured using both A-scan and intraocular lens (IOL) Master(R). Patients were divided into three groups based on AXL; Group I (AXL or = 25.5 mm). Before cataract surgery, predicted refraction was calculated using the Haigis, SRK/T, Hoffer Q, and Holladay 1 formulas using both A-scan and IOL Master(R) measurements. Mean absolute error (MAE) were analyzed at one month after surgery using the various IOL formulas. RESULTS: Using contact ultrasound biometry, in Group I, MAE of Haigis was 0.80 +/- 0.67 D and was significantly lower than that using SRK/T. In Group II, the Haigis MAE was 0.72 +/- 0.55 D and was significantly lower than the results of all other formulas. In Group III, the Haigis MAE was 0.76 +/- 1.13 D and not significantly different from the results of other formulas. Comparing MAE of A-scan to IOL Master(R), the Haigis formula showed 0.16 D higher error that decreased when the AXL was close to the normal range. CONCLUSIONS: Using contact ultrasound biometry, the Haigis formula provided the best predictability of postoperative refractive outcome compared to other formulas in eyes with normal axial length.

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.