Evaluation of the effectiveness and safety of TransPRK assisted by smart pulse technology for high myopia

Objective

To evaluate the effectiveness and safety of transepithelial photorefractive keratectomy (TransPRK) assisted by smart pluse technology (SPT) for the correction of high myopia.

Methods

An observational case series study was conducted.Sixty high myopic patients (107 eyes) with spherical equivalent (SE)≥-6.0 D who received TransPRK assisted by SPT from January to December 2016 in Eye Hospital of Wenzhou Medical University were enrolled.Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) of the patients were examined and recorded in logarithm of the minimum angle of resolution (LogMAR) units, and refraction was examined with a subjective refractometer.The healing of corneal epithelium and corneal haze was observed with a slit lamp.Intraocular pressure (IOP) was measured with the non-contact tonometer.Safety index (SI) and efficacy index (EI) were analyzed.The follow-up time was 12 months.This study protocol adhered to the Declaration of Helsinki and was approved by an Ethics Committee of Eye Hospital of Wenzhou Medical University (No.2019-197-k-177). Written informed consent was obtained from each patient prior to any medical examination.

Results

The mean epithelial healing time was (3.77±1.02) days.There were statistically significant differences in UCVA and BCVA between before and after surgery (Z=380.812, 267.313; both at P<0.001). And the 7-day, 6-month, and 12-month postoperative BCVA were better than preoperative BCVA, showing statistically significant differences (all at P<0.05). Mean SI was 1.10±0.12, and mean EI was 1.05±0.17 at 12 months after surgery.There was no significant difference between the attempted SE before surgery (-8.02±1.36)D and the achieved SE at 12 months after surgery (-8.04±1.51)D (P=0.523). SE in the predictive range within ±0.50 D accounted for 79% (85/107) and that within ±1.0 D accounted for 92% (98/107). The IOP was slightly increased in 3 eyes at 7 days and 7 eyes at 1 month after surgery, respectively, which returned to normal after the use of ophthalmic solution for lowing IOP.The incidence of haze severer than grade 1 was less than 1% (1 eye), and haze gradually disappeared after application of drugs.

Conclusions

TransPRK assisted by SPT for high myopia shows good safety, effectiveness and predictability.It is an ideal corneal surface surgery to correct high myopia.

Myopia/therapy; Lasers, excimer/therapeutic use; Treatment outcome; Transepithelial photorefractive keratectomy; Smart pulse technology; High myopia