Pietilä Juhani, Mäkinen Petri, Uusitalo Hannu
Department of Ophthalmology, University of Tampere, Medical School, Finland.
J Refract Surg. 2002 Mar-Apr;18(2):155-61. doi: 10.3928/1081-597X-20020301-10.
Regression (often combined with significant haze) and undercorrection are the most frequent complications after photorefractive keratectomy (PRK) for myopia. PRK retreatment has been used to treat both of these complications.
Sixty-three eyes (55 patients) were reoperated (PRK) because of initial regression or undercorrection. The mean interval between the operations was 17.2 months (range 5 to 37 mo). Residual myopia before retreatment was less than -5.00 D in 62 eyes (mean -2.21 +/- 0.99 D) and was -10.50 D in one eye. The same surgical PRK technique (Aesculap-Meditec MEL 60 excimer laser with 5 or 6-mm ablation zone) was used in both operations.
One-year results were available for 51 eyes. In the group of eyes with low residual myopia (<-5.00 D), mean refraction 1 year after retreatment was -0.42 +/- 0.96 D and 43 eyes (86%) were within +/-1.00 D of emmetropia. Uncorrected visual acuity of 20/40 or better was achieved in 43 eyes (86%) after 1 year. One eye lost two lines of best spectacle-corrected visual acuity after two procedures because of haze. Mean haze was the same before and 12 months after reoperation (grade 0.39 vs. 0.38). Significant haze (>2) and high regression after the first PRK occurred after reoperation. The one eye with -10.50 D residual myopia after the first PRK showed high regression, and 1 year after the reoperation refraction was -9.50 D with grade 2 haze.
Repeated PRK was safe and in most cases effective in treating regression and undercorrection in eyes with low residual myopia after initial PRK. High regression and especially haze after the initial PRK often reappeared after reoperation.
屈光回退（常伴有明显 haze）和欠矫是近视准分子激光原位角膜磨镶术（PRK）后最常见的并发症。PRK 再次手术已用于治疗这两种并发症。
63 只眼（55 例患者）因初次手术屈光回退或欠矫而接受再次手术（PRK）。两次手术的平均间隔时间为 17.2 个月（范围 5 至 37 个月）。再次手术前 62 只眼的残余近视小于-5.00D（平均-2.21±0.99D），1 只眼为-10.50D。两次手术均采用相同的 PRK 手术技术（Aesculap-Meditec MEL 60 准分子激光，消融区直径 5 或 6mm）。
51 只眼有 1 年的随访结果。在残余近视较低（<-5.00D）的眼组中，再次手术后 1 年的平均屈光度为-0.42±0.96D，43 只眼（86%）的屈光状态在正视眼±1.00D 范围内。1 年后 43 只眼（86%）的裸眼视力达到 20/40 或更好。1 只眼在两次手术后因 haze 导致最佳矫正视力下降两行。再次手术前和术后 12 个月的平均 haze 相同（分别为 0.39 级和 0.38 级）。初次 PRK 后出现明显 haze（>2 级）和高度屈光回退。初次 PRK 后残余近视-10.50D 的 1 只眼出现高度屈光回退，再次手术后 1 年屈光度为-9.50D，haze 为 2 级。
重复 PRK 治疗初次 PRK 后残余近视较低的眼的屈光回退和欠矫在大多数情况下是安全有效的。初次 PRK 后的高度屈光回退尤其是 haze 在再次手术后常再次出现。
