An evaluation of visual performance after trans-epithelial photorefractive keratectomy for correcting irregular corneal astigmatism

Objective To evaluate visual performance pre-and postoperatively in patients with irregular corneal astigmatism who were treated with topography-guided trans-epithelial photorefractive keratectomy (TPRK).Methods This non-randomized prospective clinical study was comprised of 15 eyes of 12 patients with irregular corneal astigmatism who were treated with topography-guided TPRK.The data included UCVA,BCVA,pre-and postoperative refractive data,and contrast sensitivity before surgery and at 1 and 3 months after surgery,the corneal epithelial timeline for healing,pain scores at 3 and 7 days after surgery,the classification of haze when it appeared,and the safety and efficacy indexes.Repeated measures analysis of variance was used to compare the changes over time.Results Mean UCVA increased from 4.11±0.28 preoperatively to 4.88±0.16 3 months postoperatively (F=36.706,P＜0.05).Mean BSCVA increased from 4.86±0.08 to 4.98±0.09 (F=5.075,P＜0.05),with no visual acuity lines lost.Safety and efficacy indexes were 1.025 and 1.004,respectively.Mean spherical equivalent (SE) was reduced from-3.73±4.62 D to-0.03±0.09 D (F=-4.034,P＜0.05),and the mean cylinder was reduced from-1.71±1.43 D to +0.38±1.14 D (F=-9.192,P＜0.05).Tbere were significant differences in contrast sensitivity were found between patients at 3,6,12 c/d spatial frequencies before surgery and 1 month after surgery (P＞0.05).But patients at 3 months after surgery showed better contrast sensitivity than patients before surgery (P＜0.05).Haze appeared in 2 eyes at 1 month postoperatively but recovered by 3 months postoperatively.Conclusion Topography-guided TPRK appears to be an effective treatment for irregular corneal astigmatism.The operation improves contrast sensitivity and visual performance in patients with irregular corneal astigmatism. Key words: Trans-epithelial photorefractive keratectomy;  Astigmatism;  Visual quality