CALCULATION OF LENS POWER WITH NEW BIOMETRIC FORMULAS; [LENS GÜCÜNÜN YENİ BİOMETRİ FORMÜLLERİ İLE HESAPLANMASI]

Objective: Comparison of the accuracy of six biometric formulas based on refractive findings using patients' biometric and refractive data before phacoemulsification surgery. Material and Method: A retrospective analysis was conducted of the data of 65 eyes of 43 patients who underwent phacoemulsification at the Ophthalmology Department of Istanbul University Istanbul Faculty of Medicine between January 2016 and July 2019. The intraocular lens (IOL) power corresponding to the target refraction value in patients was calculated using the SRK/T formula. The patients' final refraction values were obtained by examinations conducted after the third postoperative month. After implanting IOLs with the same refractive power, target refraction values were calculated using the optical biometry measurements of the patients and the Hoffer Q, T2, Ladas Super Formula (Ladas), Barrett Universal II (BU II), and Hill-RBF formulas. The refractive refraction deviation values between the formulas were compared, as well as the difference between the target refraction values determined by the formulas and the spherical equivalents of the patients' result refractions. Result: The normal age of the 43 patients in the study was 64.65±8.23 (47-86) years. The mean axial length was 23.5±0.7mm (22.01-24.5). The refractive deviation was 0.29±0.29 D with SRK/T, 0.27±0.27 D with T2, 0.3±0.24 D with Hoffer Q, 0.3±0.26 D with Ladas, and 0.33±0.28 D with BU II, and 0.27±0.29 D with Hill-RBF. The refractive deviation percentages of the formulas in the range of -1.00 D to +1.00 D were as follows: 98.5% Hoffer Q and Hill-RBF; 96.9% T2, Ladas, BU II, and SRK/T. In terms of refractive deviation values, there was no statistically significant difference between the formulas (p>0.05). Conclusion: The probability of obtaining the target refractive value with a refractive deviation within ±1 D of the six biometry formulas included in the study is 96.9% and higher. Any of these formulas can be employed safely to compute preoperative IOL power in the eyes of normal length. © 2024 Authors.