Aims To evaluate the bilateral changes in the sub-basal nerve plexus of the cornea and ocular surface function after unilateral small incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (tPRK) procedures. Methods 34 patients were enrolled in the study and underwent unilateral SMILE (21 of 34 patients) or unilateral tPRK (13 of 34 patients). Complete ophthalmic examinations, tear film function tests and Cochet-Bonnet esthesiometry were conducted to assess the effects of the surgeries on the corneal nerves and tear function. Morphological changes were assessed using in vivo confocal microscopy to evaluate the corneal sub-basal nerve plexus and dendritic cells. ELISA was used to measure the tear neuromediators. Clinical and morphological data at each follow-up point were compared with preoperative baseline values. Results All patients who underwent unilateral SMILE or tPRK procedures exhibited bilateral corneal nerve degenerative changes, decreased corneal sensitivity, worsening of dry eye symptoms and changes in bilateral tear neuromediators. In the SMILE group, bilateral corneal sensitivity was positively correlated with corneal nerve fibre length and negatively correlated with dendritic cell area. The dry eye severity was negatively correlated with corneal sensitivity. Tear levels of substance P and nerve growth factor were positively correlated with mean dendritic cell area and dry eye severity, but negatively correlated with corneal sensitivity. In the tPRK group, bilateral corneal sensitivity was positively correlated with corneal nerve fibre density. Conclusions Unilateral refractive surgery may bilaterally affect the morphology and function of corneal nerves and ocular surface status postoperatively. Data are available upon reasonable request.

中文翻译：

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单侧 SMILE 和 tPRK 后双眼角膜神经支配和眼表功能的结构和功能变化


目的 评估单侧小切口微透镜摘除术 （SMILE） 和跨上皮光折射角膜切除术 （tPRK） 术后角膜基底下神经丛和眼表功能的双侧变化。方法 34 例患者纳入研究并接受单侧 SMILE （34 例患者中 21 例） 或单侧 tPRK （34 例患者中 13 例）。进行完整的眼科检查、泪膜功能测试和 Cochet-Bonnet 美学测定，以评估手术对角膜神经和泪液功能的影响。使用体内共聚焦显微镜评估形态学变化，以评估角膜基底下神经丛和树突状细胞。ELISA 用于测量撕裂神经介质。将每个随访点的临床和形态学数据与术前基线值进行比较。结果 所有接受单侧 SMILE 或 tPRK 手术的患者均表现出双侧角膜神经退行性改变、角膜敏感性降低、干眼症状恶化和双侧泪液神经介质变化。在 SMILE 组中，双侧角膜敏感性与角膜神经纤维长度呈正相关，与树突状细胞面积呈负相关。干眼症严重程度与角膜敏感性呈负相关。P 物质和神经生长因子的泪液水平与平均树突状细胞面积和干眼症严重程度呈正相关，但与角膜敏感性呈负相关。在 tPRK 组中，双侧角膜敏感性与角膜神经纤维密度呈正相关。结论 单侧屈光手术可能影响术后双侧角膜神经的形态和功能及眼表状态。 数据可根据合理要求提供。