Tian Mingxia, Ma Ping, Mu Guoying, Chen Lijing, Feng Jie
Department of Ophthalmology, Jining No. 1 People's Hospital Affiliated to Jining Medical College, No. 6 Jiankang Road, Jining, Shandong, China.
Department of Ophthalmology, Shandong Provincial Hospital Affiliated to Shandong University, No. 324 Jingwuweiqi Road, Jinan, Shandong, China.
J Ophthalmol. 2020 Jul 14;2020:9834760. doi: 10.1155/2020/9834760. eCollection 2020.
To establish a porcine eye model for manual sub-Bowman layer photorefractive keratomileusis (SBPRK), which is a reformed surface ablation refractive surgery that results in preserving the corneal Bowman layer (BL).
The SBPRK group consisted of eleven eyes of 8 healthy pigs with BL flaps by mechanical technique followed by laser ablation. Regarding the remaining 5 eyes, 3 random eyes had transepithelium photorefractive keratectomy (TransPRK) (the TransPRK group), while the other 2 eyes were untreated (the blank control group). All the pigs were followed up for 8 weeks. Slit-lamp biomicroscopy and optical coherence tomography (OCT) were examined before the surgeries and at 1 week, 4 weeks, and 8 weeks after the surgeries.
In a few days after the surgery, 3 eyes of the SBPRK group were excluded from the study because of poor healing of the corneal flaps. At the 1 postoperative week, one eye had an irregular defect of about 3 mm in the central corneal epithelium area; the cornea of the other 7 eyes had just light edema with intact epithelium just like the cornea of the TransPRK group. At the 4 week, in the SBPRK group, the cornea was slightly hazy (haze stage 1). While in the TransPRK group, the cornea was hazier (haze stage 2). At the 8 week, in the SBPRK group, both corneas were almost transparent, and the edges of the BL flaps could not be clearly seen. Meanwhile, in the TransPRK group, the corneal haze became lighter and thinner. OCT showed that, in the SBPRK group, there was high reflection in the BL layer, and it was obvious at 1 week postoperation, decreased at 4 weeks, and calmed down at 8 weeks. However, in the TransPRK group, the high reflection diffused in the anterior corneal stroma at 1 week postoperation, enhanced at 4 weeks, and weakened at 8 weeks.
Preserving the BL while conducting surface refractive surgery may result in less haze than TransPRK. However, further study is still needed, and this technique still requires refining until it becomes a standard clinical procedure.
建立一种用于手动准分子激光上皮瓣下角膜磨镶术（SBPRK）的猪眼模型，SBPRK是一种改良的表面消融屈光手术，可保留角膜前弹力层（BL）。
SBPRK组由8只健康猪的11只眼组成，通过机械技术制作BL瓣，随后进行激光消融。其余5只眼中，随机选取3只眼行经上皮准分子激光角膜切削术（TransPRK）（TransPRK组），另外2只眼不做处理（空白对照组）。所有猪均随访8周。术前及术后1周、4周和8周进行裂隙灯生物显微镜检查和光学相干断层扫描（OCT）。
术后数天，SBPRK组有3只眼因角膜瓣愈合不良被排除在研究之外。术后1周，1只眼中央角膜上皮区域有一个约3毫米的不规则缺损；其他7只眼的角膜仅有轻度水肿，上皮完整，与TransPRK组的角膜情况相同。术后4周，SBPRK组角膜轻度混浊（混浊1期）。而TransPRK组角膜混浊更明显（混浊2期）。术后8周，SBPRK组两只角膜几乎透明，BL瓣边缘无法清晰看到。同时，TransPRK组角膜混浊变轻变薄。OCT显示，SBPRK组BL层有高反射，术后1周明显，4周时降低，8周时趋于稳定。然而，TransPRK组术后1周高反射在前角膜基质中弥漫分布，4周时增强，8周时减弱。
在进行表面屈光手术时保留BL可能比TransPRK产生的混浊更少。然而，仍需要进一步研究，并且该技术仍需完善，直到成为标准的临床程序。
