Abstract：
OBJECTIVE: The aim of this study was to describe a new surgical technique for flattening the corneal curvature and to reduce progression in eyes with advanced progressive keratoconus (KC) by using Bowman layer (BL) onlay grafting and to report on the preliminary outcomes of this procedure.
METHODS: In this prospective interventional case series, 5 patients with advanced progressive KC underwent BL onlay grafting. After removal of the epithelium, a BL graft was placed and \"stretched\" onto the stroma, and a bandage lens was placed to cover the BL graft. In 1 case, BL onlay grafting could be performed immediately after ultraviolet corneal crosslinking; all other eyes were ineligible for ultraviolet corneal crosslinking. Best spectacle- and/or best contact lens-corrected visual acuity, refraction, biomicroscopy, corneal tomography, anterior segment optical coherence tomography, and complications were recorded at 1 week and at 1, 3, 6, 9, and 12 to 15 months postoperatively.
RESULTS: All 5 surgeries could be performed successfully. Average maximum keratometry went from 75 diopters (D) preoperatively to 70 D at 1 year postoperatively. All eyes showed a completely reepithelialized and a well-integrated graft. Best spectacle-corrected visual acuity improved at least 2 Snellen lines (or more) in 3 of 5 cases and best contact lens-corrected visual acuity remained stable, improving by 3 Snellen lines in case 1 at 15 months postoperatively. Satisfaction was high, and all eyes again had full contact lens tolerance.
CONCLUSIONS: BL onlay grafting may be a feasible surgical technique, providing up to -5 D of corneal flattening in eyes with advanced KC.
METHODS: In this prospective interventional case series, 5 patients with advanced progressive KC underwent BL onlay grafting. After removal of the epithelium, a BL graft was placed and \"stretched\" onto the stroma, and a bandage lens was placed to cover the BL graft. In 1 case, BL onlay grafting could be performed immediately after ultraviolet corneal crosslinking; all other eyes were ineligible for ultraviolet corneal crosslinking. Best spectacle- and/or best contact lens-corrected visual acuity, refraction, biomicroscopy, corneal tomography, anterior segment optical coherence tomography, and complications were recorded at 1 week and at 1, 3, 6, 9, and 12 to 15 months postoperatively.
RESULTS: All 5 surgeries could be performed successfully. Average maximum keratometry went from 75 diopters (D) preoperatively to 70 D at 1 year postoperatively. All eyes showed a completely reepithelialized and a well-integrated graft. Best spectacle-corrected visual acuity improved at least 2 Snellen lines (or more) in 3 of 5 cases and best contact lens-corrected visual acuity remained stable, improving by 3 Snellen lines in case 1 at 15 months postoperatively. Satisfaction was high, and all eyes again had full contact lens tolerance.
CONCLUSIONS: BL onlay grafting may be a feasible surgical technique, providing up to -5 D of corneal flattening in eyes with advanced KC.
摘要：
目的：这项研究的目的是描述一种新的手术技术，通过使用Bowman层（BL）覆盖移植来平坦化晚期进行性圆锥角膜（KC），并报告该手术的初步结果。
方法：在这个前瞻性介入病例系列中，5例晚期进行性KC患者行BL嵌体移植术。去除上皮后，放置BL移植物并“拉伸”到基质上，并放置绷带透镜以覆盖BL移植物。在1种情况下，可以在紫外线角膜交联后立即进行BL嵌体移植；所有其他眼睛都不适合进行紫外线角膜交联。最佳眼镜和/或最佳隐形眼镜矫正视力，折射,生物显微镜,角膜断层扫描,眼前节光学相干断层扫描，并记录术后1周和术后1,3,6,9和12~15个月的并发症.
结果：所有5例手术均可成功进行。平均最大角膜屈光度从术前的75屈光度（D）增加到术后1年的70D。所有的眼睛都显示出完全的上皮化和完整的移植物。在5例中的3例中，最佳眼镜矫正视力至少改善了2条Snellen线（或更多），最佳隐形眼镜矫正视力保持稳定，病例1在术后15个月改善了3条Snellen线。满意度很高,所有的眼睛都有完全的隐形眼镜耐受性。
结论：BL嵌体移植可能是一种可行的手术技术，在具有高级KC的眼睛中提供高达-5D的角膜展平。
方法：在这个前瞻性介入病例系列中，5例晚期进行性KC患者行BL嵌体移植术。去除上皮后，放置BL移植物并“拉伸”到基质上，并放置绷带透镜以覆盖BL移植物。在1种情况下，可以在紫外线角膜交联后立即进行BL嵌体移植；所有其他眼睛都不适合进行紫外线角膜交联。最佳眼镜和/或最佳隐形眼镜矫正视力，折射,生物显微镜,角膜断层扫描,眼前节光学相干断层扫描，并记录术后1周和术后1,3,6,9和12~15个月的并发症.
结果：所有5例手术均可成功进行。平均最大角膜屈光度从术前的75屈光度（D）增加到术后1年的70D。所有的眼睛都显示出完全的上皮化和完整的移植物。在5例中的3例中，最佳眼镜矫正视力至少改善了2条Snellen线（或更多），最佳隐形眼镜矫正视力保持稳定，病例1在术后15个月改善了3条Snellen线。满意度很高,所有的眼睛都有完全的隐形眼镜耐受性。
结论：BL嵌体移植可能是一种可行的手术技术，在具有高级KC的眼睛中提供高达-5D的角膜展平。
