Acta ophthalmologica · 2022
Predictive factors of posterior corneal shift after small incision lenticule extraction: a 5-year follow-up study.
СтатьяНазвание и аннотация: Перевод пока не подготовлен
Обработка статьи · этапы, ошибки и управление
Загрузка состояния…
Ошибки и ограничения
История · было → стало
Состояние обновляется каждые 5 секунд, пока блок открыт. Процент показывается только там, где известен объём работы. Пауза останавливает продолжение этапа; текущий запрос к источнику может завершиться.
Cao Huazheng, Zhang Lin, Liang Shuang, Chen Xuan, Jhanji Vishal, Wang Yan
Аннотация
PURPOSE: The aim of this study was to determine risk factors affecting changes in posterior corneal elevation (PCE) and predict the 5-year stability after small incision lenticule extraction (SMILE).
METHODS: This retrospective, longitudinal study enrolled 161 patients post-SMILE. The PCE values were measured at the apex, thinnest, maximal and 24 other prespecified preoperative points and at 6 months, 1 year and 5 years postoperatively.
RESULTS: Posterior corneas exhibited time-dependent, region-dependent and angle-dependent changes. For every dioptre increase in the absolute preoperative spherical equivalent (SE), 10-μm decrease in the central corneal thickness (CCT), 10-μm increase in the maximum lenticule thickness (MLT), 10-μm decrease in the residual bed thickness (RBT), 10% increase in the percentage ablation depth (PAD, MLT divided by CCT) and 10% decrease in the percentage stromal bed thickness (PSBT, RBT divided by CCT), PCE exhibited average forward displacements of 0.2-0.4, 0.2-0.7, 0.1-0.2, 0.1-0.3, 0.6-1.0 and 0.5-1.1 μm, respectively (p < 0.05). PSBT was the variable with the highest accuracy in predicting 5-year stability of posterior corneas (area under curve = 0.75). The cut-off values of SE, CCT, MLT, RBT, PAD and PSBT for increased PCE were -8.00 to -8.31 D, 481.0-498.5 μm, 139.5-144.5 μm, 255.5-263.5 μm, 26.9-28.3% and 48.9-52.6%, respectively.
CONCLUSION: Eyes with thinner corneas, higher myopia requiring greater MLT and lower RBT exhibited greater predispositions towards posterior protrusion. The thresholds for preventing forward posterior corneal displacement were 26.9-28.3% for PAD and 48.9-52.6% for PSBT. Prediction of posterior corneal stability is useful for assessing surgical risks post-SMILE.
METHODS: This retrospective, longitudinal study enrolled 161 patients post-SMILE. The PCE values were measured at the apex, thinnest, maximal and 24 other prespecified preoperative points and at 6 months, 1 year and 5 years postoperatively.
RESULTS: Posterior corneas exhibited time-dependent, region-dependent and angle-dependent changes. For every dioptre increase in the absolute preoperative spherical equivalent (SE), 10-μm decrease in the central corneal thickness (CCT), 10-μm increase in the maximum lenticule thickness (MLT), 10-μm decrease in the residual bed thickness (RBT), 10% increase in the percentage ablation depth (PAD, MLT divided by CCT) and 10% decrease in the percentage stromal bed thickness (PSBT, RBT divided by CCT), PCE exhibited average forward displacements of 0.2-0.4, 0.2-0.7, 0.1-0.2, 0.1-0.3, 0.6-1.0 and 0.5-1.1 μm, respectively (p < 0.05). PSBT was the variable with the highest accuracy in predicting 5-year stability of posterior corneas (area under curve = 0.75). The cut-off values of SE, CCT, MLT, RBT, PAD and PSBT for increased PCE were -8.00 to -8.31 D, 481.0-498.5 μm, 139.5-144.5 μm, 255.5-263.5 μm, 26.9-28.3% and 48.9-52.6%, respectively.
CONCLUSION: Eyes with thinner corneas, higher myopia requiring greater MLT and lower RBT exhibited greater predispositions towards posterior protrusion. The thresholds for preventing forward posterior corneal displacement were 26.9-28.3% for PAD and 48.9-52.6% for PSBT. Prediction of posterior corneal stability is useful for assessing surgical risks post-SMILE.