Intrastromal corneal ring segment implantation for ectasia after refractive surgery

ABSTRACTPurpose:To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS) implantation to correct ectasia in eyes with prior refractive surgery.Methods:Forty-one eyes of 25 patients (13 men, 12 women; mean age, 28.66 years) with ectasia after refractive surgery [photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK)] were included in a nonrandomized, retrospective, observational case series. Corneal tunnels were created by mechanical dissection in all eyes. Main outcome measures included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), refraction, keratometry, and computerized analysis of corneal topography. Patients were divided into two groups by the type of refractive surgery (Group A: PRK, Group B: LASIK).Results:The mean preoperative manifest astigmatism decreased from -1.88 to -0.84 D in Group A (p=0.096) and -3.18 to -1.77 D in Group B (p=0.000). The mean keratometric astigmatism decreased from -2.58 to -1.66 D in Group A (p=0.010) and -4.80 to -2.78 D in Group B (p=0.000). The mean spherical equivalent decreased from -2.97 to -2.05 D in Group A (p=0.065) and -3.31 to -2.42 D in Group B (p=0.014). No significant between-group differences were noted on the comparison of preoperative and postoperative results. No intraoperative or postoperative complications were observed.Conclusion:ICRS implantation is a useful treatment option for ectasia following refractive surgery, and it has significantly reduced the refractive cylinder and increased best spectacle-corrected visual acuity.

摘要
目的：评估角膜基质内环形植入物（intrastromal corneal ring segment, ICRS）植入术用于矫正既往接受屈光手术后并发角膜扩张患者的临床疗效。
方法：本研究为非随机回顾性观察病例系列研究，纳入25例患者共41只眼（男13例，女12例；平均年龄28.66岁），均为屈光手术[准分子激光屈光性角膜切削术（photorefractive keratectomy, PRK）或准分子激光原位角膜磨镶术（laser in situ keratomileusis, LASIK）]后出现角膜扩张的病例。所有患眼均通过机械分离法制作角膜隧道。主要观察指标包括裸眼视力（uncorrected visual acuity, UCVA）、最佳框架眼镜矫正视力（best spectacle-corrected visual acuity, BCVA）、屈光状态、角膜曲率以及角膜地形图的计算机分析结果。根据既往屈光手术类型将患者分为两组：A组（PRK组）与B组（LASIK组）。
结果：A组术前平均显性散光由-1.88 D降至-0.84 D（p=0.096），B组由-3.18 D降至-1.77 D（p=0.000）。A组术前平均角膜曲率性散光由-2.58 D降至-1.66 D（p=0.010），B组由-4.80 D降至-2.78 D（p=0.000）。A组术前平均球镜等效度数由-2.97 D降至-2.05 D（p=0.065），B组由-3.31 D降至-2.42 D（p=0.014）。两组术前与术后结果的组间比较均无显著差异。术中及术后均未观察到相关并发症。
结论：角膜基质内环形植入物植入术是屈光手术后角膜扩张的有效治疗手段，可显著降低屈光散光并提升最佳框架眼镜矫正视力。