CALCULATION OF LENS POWER WITH NEW BIOMETRIC FORMULAS

Year 2023, Volume: 86 Issue: 4, 312 - 318, 01.12.2023

Elif Ergül Emre Altınkurt Adem Uğurlu Semih Çakmak Nilüfer Gözüm

https://doi.org/10.26650/IUITFD.1260293

Abstract

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.

Keywords

Cataract surgery, biometrics, new generation formulas

LENS GÜCÜNÜN YENİ BİOMETRİ FORMÜLLERİ İLE HESAPLANMASI

Abstract

Amaç: Hastaların fakoemülsifikasyon cerrahisi öncesindeki biometrik ve refraktif verileri kullanılarak, altı biometrik formülün refraktif sonuçlara göre doğruluklarının karşılaştırılması.
Gereç ve Yöntem: Retrospektif olarak 2016 Ocak ve 2019 Temmuz tarihleri arasında İstanbul Üniversitesi İstanbul Tıp Fakültesi Göz Hastalıkları kliniğinde fakoemülsifikasyon uygulanan 43 hastanın 65 gözünün verileri retrospektif olarak incelendi. Hastalarda hedeflediğimiz refraksiyon değerine karşılık gelen göz içi lens (GİL) gücü SRK/T formülüne göre hesaplandı. Postoperatif 3. aydan sonra yapılan muayenelerde hastaların sonuç refraksiyon değerleri saptandı. Hastaların optik biometri ölçümleri kullanılarak, aynı kırma gücüne sahip GİL implante edildiğinde, Hoffer Q, T2, Ladas Süper Formülü (Ladas), Barrett Universal II (BU II) ve Hill-RBF formüllerine göre hedef refraksiyon değerleri hesaplandı. Formüllerin saptadığı hedef refraksiyon değerleriyle, hastaların sonuç refraksiyonlarının sferik eşdeğerleri arasındaki fark alındı ve formüller arasındaki refraktif sapma değerleri karşılaştırıldı.
Bulgular: Çalışmaya alınan 43 hastanın yaş ortalaması 64,65±8,23 (47-86) yıl idi. Ortalama aksiyel uzunluk 23,5±0,7mm (22,01-24,5) olarak saptandı. SRK/T ile refraktif sapma 0,29±0,29 D, T2 ile 0,27±0,27 D, Hoffer Q ile 0,3±0,24 D, Ladas ile 0,3±0,26 D, BU II ile 0,33±0,28 D, Hill-RBF ile 0,27±0,29 D idi. Formüllerin -1,00 D ile +1,00 D aralığında bulunan refraktif sapma yüzdeleri şu şekildeydi: %98,5 Hoffer Q ve Hill-RBF; %96,9 T2, Ladas, BU II ve SRK/T. Refraktif sapma değerleri açısından formüller arasında istatistiksel olarak anlamlı bir farklılık izlenmedi (p>0,05).
Sonuç: Çalışmada yer alan altı biometri formülünün ±1 D içinde refraktif sapma ile hedef refraktif değere ulaşma şansı %96,9 ve üzerindedir. Bu formüllerin her biri normal uzunluktaki gözlerde preoperatif GİL gücünü hesaplamak için güvenli bir şekilde kullanılabilir.

Keywords

Katarakt cerrahisi, biometri, yeni jenerasyon formüller

Thanks

Prof. Dr. Nilüfer Gözüm'e öneri, destek ve katkıları için teşekkür ederim.

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