1.5 디옵터 이상의 각막 난시에서 난시 각막굴절콘택트렌즈의 효과

Effect of Toric Orthokeratology Lenses on Patients with More Than 1.5 Diopter of Corneal Astigmatism

목적: 1.5 디옵터(D) 이상의 각막난시를 가진 근시 환자에게 난시 각막굴절교정 렌즈의 효과를 알아보고자 하였다. 대상과 방법: 각막난시로 인해 구면 각막굴절교정 렌즈의 처방이 불가능하거나 실패하여 난시 각막굴절교정 렌즈(Toric Ortho-KLKTM, Lucid Korea, Seoul, Korea)를 처방 받아 6개월 이상 착용한 17명 24안을 대상으로 착용 전후 시력, 굴절이상, 각막변화와함께 각막 및 굴절 난시와 렌즈 난시, 그리고 각막난시와 나안시력 호전 정도와의 상관관계를 알아보았다. 결과: 렌즈 착용 후 나안시력(logMAR)은 0.93 ± 0.13에서 0.09 ± 0.07로 의미 있게 호전되었다(p＜0.001). 구면굴절 이상값(p ＜0.001), 원주굴절 이상값(p=0.008), 구면대응값(p＜0.001)은 모두 유의한 감소를 보였다. Simulated K (Sim K) 값은 모두 유의하게 편평해진 변화를 보이고(p＜0.001), 편심률은 유의하게 감소되었으나(p＜0.001), 각막난시는 통계적으로 유의한 차이를 보이지 않았다(p=0.803). 렌즈난시는 각막난시와는 유의한 상관관계를 보였으나(r=0.526, p=0.012), 굴절난시와는 상관관계가 없었으며(r=0.218,p=0.329), 각막난시의 정도는 나안시력 호전 정도와는 연관성이 없는 것으로 나타났다(r=0.1804, p=0.399). 결론: 구면 렌즈의 처방이 어려웠던 각막난시 환자에서 난시 각막굴절교정 렌즈는 근시 및 난시 교정에 유용하여 효과적인 치료로 생각되며, 렌즈의 난시도는 각막난시도와 관련성이 높았고, 각막난시의 정도가 높더라도 나안시력 호전에는 영향을 끼치지 않았다.

Purpose: To report the effect of toric orthokeratology lenses on myopic patients who have more than 1.5 diopter (D) of corneal astigmatism. Methods: Seventeen patients (24 eyes) who wore toric orthokeratology lenses for more than 6 months were recruited for this study. The uncorrected visual acuity (UCVA), refractive error and keratometric changes including eccentricity before and after wearing lenses were compared. The correlations between corneal astigmatism as well as refractive astigmatism and lens toricity and between corneal astigmatism and improvement of UCVA after lens fitting were assessed. Results: After wearing lenses, UCVA (log MAR) was significantly improved from 0.93 ± 0.13 to 0.09 ± 0.07 (p < 0.001). Myopia changed from -4.53 ± 1.55 D to -0.67 ± 0.80 D (p < 0.001), refractive astigmatism from -1.48 ± 0.71 D to -0.99 ± 0.72 (p = 0.008) and spherical equivalent from -5.27 ± 1.56 D to -1.12 ± 0.92 D (p < 0.001). Simulated K (Sim K) tended to be more flat (p < 0.001)and the eccentricity was significantly decreased from 0.45 ± 0.08 to -0.69 ± 0.45 (p < 0.001), but corneal astigmatism was not significantly changed from 2.05 ± 0.41 D to 2.01 ± 0.98 D (p = 0.803). Correlation between corneal astigmatism and lens toricity was statistically significant (r = 0.526, p = 0.012) but not between refractive astigmatism and lens toricity (r = 0.218, p = 0.329). The amount of corneal astigmatism was not correlated with the improvement of uncorrected visual acuity after lens fitting (r = 0.1804, p= 0.399). Conclusions: Toric orthokeratology lenses might be an effective treatment in patients with corneal astigmatism who cannot be fitted with spherical orthokeratology lenses. Lens toricity was correlated with corneal astigmatism and the amount of corneal astigmatism did not affect the improvement of uncorrected visual acuity after lens fitting.