Comparison of Corneal Keratometry Measured by Three Different Methods

Year 2024, Volume: 11 Issue: 3, 180 - 186, 18.12.2024

Konuralp Yakar , Göksu Alaçamlı

https://doi.org/10.47572/muskutd.1523840

Abstract

To compare and evaluate the interchangeability and agreement between corneal keratometry measurements (flattest-steepest keratometry, mean keratometry and corneal astigmatism) using partial coherence interferometry reflectometry optical biometry (Nidek AL Scan, 2.4–3.3 mm zones, Nidek Technologies, Gamagori, Japan), corneal aberrometer/topographer (Nidek OPD Scan II, Nidek Technologies, Gamagori, Japan) and standard autorefractokeratometer (Topcon KR 8900, Topcon Inc., Tokyo, Japan) a total of 360 right eyes of 360 healthy volunteers with a mean age of 24.37±3.91 years were enrolled in this prospective comparative study. Paired t-tests were used to evaluate pairwise comparisons. The Bland–Altman test with 95% limits of agreement was used to evaluate the agreement between the three devices. There were no statistically significant differences between all keratometric values of the Nidek AL Scan obtained in the 2.4 and 3.3 mm zones (p>0.05). There were no statistically significant differences in AstK values between the Nidek AL Scan (2.4 -3.3 mm zone) and the Nidek OPD Scan II pairwise comparisons (p>0.05). When the K1, K2, and Kmean values measured with the Nidek OPD Scan II and Topcon KR 8900 were compared with the Nidek AL Scan (2.4 -3.3 mm zone), a statistically significant difference was found (p<0.05). AstK values were also statistically different between Topcon KR 8900 versus Nidek AL Scan (2.4 -3.3 mm zone) and Nidek OPD Scan II (p<0.05). Only the Nidek AL Scan provided comparable measurements for all keratometric parameters analyzed in the 2.4 and 3.3 mm zones. The LoA obtained for each inter-device agreement should be analyzed carefully to consider the interchangeability of these three devices.

Keywords

AL Scan, Biometry, Keratometry, OPD Scan, Topcon Autorefractokeratometre

Farklı Üç Yöntemle Ölçülen Korneal Keratometrik Verilerin Karşılaştırılması

Abstract

Kısmi koherens interferometri reflektometri optik biyometri (Nidek AL Scan, 2.4-3.3 mm zonlar, Nidek Teknoloji, Gamagori, Japonya), korneal aberrometre/topograf (Nidek OPD Scan II, Nidek Teknoloji, Gamagori, Japonya) ve standart otorefraktokeratometre (Topcon KR 8900, Topcon, Tokyo, Japonya) cihazları kullanılarak elde edilen korneal keratometri ölçümleri (en düz-en dik keratometri, ortalama keratometri ve korneal astigmatizma) arasındaki değiştirilebilirliği ve uyumu test etmek için yapılan bu prospektif karşılaştırmalı çalışmaya yaş ortalaması 24.37±3.91 yıl olan 360 sağlıklı gönüllünün 360 sağ gözü dahil edildi. İkili karşılaştırmaları değerlendirmek için eşleştirilmiş t-testi kullanıldı. Üç cihaz arasındaki uyumu değerlendirmek için %95 uyum sınırları ile Bland-Altman testi kullanıldı. Nidek AL Scan'in 2.4 ve 3.3 mm bölgelerinde elde edilen tüm keratometrik değerleri arasında istatistiksel olarak anlamlı bir fark yoktu (p>0.05). Nidek AL Scan (2.4 -3.3 mm bölgesi) ve Nidek OPD Scan II in ikili karşılaştırmaları arasında AstK değerleri açısından istatistiksel olarak anlamlı bir fark saptanmadı (p>0.05). Nidek OPD Scan II ve Topcon KR 8900 ile ölçülen K1, K2 ve ortalama K değerleri Nidek AL Scan (2.4 -3.3 mm bölge) ile ikili karşılaştırıldığında, istatistiksel olarak anlamlı bir fark olduğu görüldü (p<0.05). AstK değerleri de Topcon KR 8900 ile Nidek AL Scan (2.4 -3.3 mm zonlar) ve Nidek OPD Scan II arasında istatistiksel olarak farklıydı (p<0.05). Sadece Nidek AL Scan, kendi içinde 2.4 ve 3.3 mm korneal zonlarda elde edilen tüm keratometrik parametreler için karşılaştırılabilir ölçümler sağlamıştır. Her bir cihazlar arası uyum için elde edilen %95 uyum sınırlarının geniş olması (>1.0 D) bu üç cihazın birbirinin yerine kullanılamayacağını düşündürmektedir.

Keywords

AL Scan, Biyometri, Keratometri, OPD Scan, Topcon Otorefraktometre

Ethical Statement

samsun 19 mayıs üniversitesi 14.12.2023

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