Long-term outcomes with Boston type 1 keratoprosthesis in ocular burns

ABSTRACT Purpose: To evaluate the long-term outcomes of Boston type I keratoprosthesis (B-Kpro) in the management of patients with ocular burn injuries. Methods: This prospective study included all patients with ocular burns who underwent B-Kpro implantation at a tertiary eye care center between February 2008 and November 2015. Twelve patients (12 eyes) were enrolled. The procedures performed for managing ocular injury were identified, and information on ocular history, surgical procedures performed, and postoperative outcomes was collected. The main outcome measures were visual acuity, prosthesis retention, postoperative complications, and required surgical procedures. Results: Twelve eyes from 12 patients met the inclusion criteria for B-Kpro implantation, including nine eyes with alkali burns and three eyes with thermal burns. A total of 13 B-Kpro devices were implanted in the 12 eyes. The mean follow-up period was 60.8 months (range, 13-91 months). Preoperative best-corrected visual acuity ranged from counting fingers to light perception. Postoperative best-corrected visual acuity was better than 20/200 in 83.3%, 66.6%, and 57.1% of patients at 12, 48, and 60 months, respectively. The initial keratoprosthesis was retained in 10 (83.3%) eyes and was successfully replaced in one eye. The major cause of worsening of initial visual acuity was advanced glaucoma (four of 12 eyes). Conclusion: The anatomical and functional results support the use of B-Kpro for managing bilateral limbal stem cell deficiency secondary to ocular burns. However, glaucoma should be carefully evaluated, as it is a continuous threat that may result in irreversible visual loss in this population.

ABSTRACT
目的：评估波士顿I型人工角膜（Boston type I keratoprosthesis, B-Kpro）治疗眼烧伤患者的长期临床疗效。
方法：本前瞻性研究纳入2008年2月至2015年11月间，于某三级眼科中心接受B-Kpro植入术的眼烧伤患者，共纳入12例患者（12只患眼）。研究收集了患者的眼部病史、实施的手术操作情况及术后转归等相关资料，并明确了针对眼外伤的处置手术。主要结局指标包括最佳矫正视力、假体留存率、术后并发症及需实施的额外手术。
结果：符合B-Kpro植入纳入标准的12只患眼来自12例患者，其中碱烧伤患眼9只，热烧伤患眼3只。12只患眼共植入13枚B-Kpro装置。平均随访时长为60.8个月（范围13~91个月）。术前最佳矫正视力范围为数指至光感。术后12、48及60个月时，最佳矫正视力优于20/200的患者占比分别为83.3%、66.6%及57.1%。初始植入的人工角膜假体留存率为83.3%（10只眼），另有1只眼成功完成假体置换。初始视力下降的主要原因为进展性青光眼（12只眼中共4例）。
结论：本研究的解剖及功能结局支持采用B-Kpro治疗眼烧伤继发的双侧角膜缘干细胞缺乏症。但需对青光眼进行严密评估，因其为本患者群体中可能导致不可逆视力丧失的持续性危险因素。