KHẢO SÁT LOẠN THỊ GIÁC MẠC THEO NGUYÊN LÝ SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY Ở BỆNH NHÂN ĐỤC THỂ THỦY TINH CÓ CHỈ ĐỊNH PHẪU THUẬT

Abstract

Objectives: To investigate the characteristics of corneal astigmatism measured by Swept-Source optical coherence tomography (SS-OCT) in cataract patients aged > 60 years and to evaluate the correlations among different astigmatic components. Methods: The cross-sectional descriptive study included 247 eyes of 208 patients examined at Military Hospital 103, from July 2025 to March 2026. Corneal astigmatic parameters were directly measured using the Anterion. Results: Total corneal astigmatism (TCA) was significantly higher than anterior corneal astigmatism (ACA) (1.05 ± 0.74D vs. 0.91 ± 0.65D); p < 0.001. Posterior corneal astigmatism (PCA) was -0.29 ± 0.14D, with 96.4% demonstrating against-the-rule (ATR) astigmatism in optical terms, leading to significant alterations in TCA, including a reduction of 0.16D in with-the-rule (WTR) astigmatism and increases of 0.34D and 0.12D in ATR and oblique astigmatism, respectively. PCA also induced axis shifts, particularly in eyes with anterior WTR and oblique astigmatism. Vector analysis confirmed a predominance of ATR astigmatism in the study population (J₀ = -0.25) and demonstrated a strong correlation between TCA and ACA, as well as a moderate correlation with PCA. Conclusion: PCA is an integral component of TCA and has a significant impact on overall corneal astigmatic power. Reliance solely on ACA measurements may lead to errors in both magnitude and axis estimation of true corneal astigmatism in the elderly.