Efficacy And Safety Of PTK And PRK Combined With CXL On The Post-LASIK Keratectasia

BackgroundIn recent years,with the increase patients of myopia,the demand for refractive surgery is becoming more and more.LASIK(Laser in situ keratomileusis),the excimer laser in situ keratomileusis,is widely used in the correction of ametropia because of its advantages of strong predictability,high accuracy,safety and efficacy.The main operation is in the intercorneal interlamellar,in order to keep the corneal surface tissue completely,to reduce the possibility of corneal opacity caused by corneal epithelial hyperplasia.It has the advantages of good corneal transparency and quick recovery after operation.But at the same time,there are many LASIK related complications have been reported,among them post-LASIK keratecatasia is one of the complications that seriously danger the visual function of the patients.The main manifestations are the conical protuberance of the central cornea,the increase Kmax of the corneal curvature and the progressive visual acuity,that are difficult to be completely corrected by the frame glasses.It is a huge threat to the postoperative visual quality of patients,and there is no safe and effective targeted therapy.The combination treatment of CXL with PTK and PRK was used for the treatment of postoperative keratecatasia,and the above combined treatment was analyzed and evaluated on its safety and efficacy.The combined treatment is aimed to delay the progression of post-LASIK keratectasia and reconstruct the refraction,in order to improve the patient' s visual quality at its extend.ObjectiveTo evaluate the efficacy and safety of PTK,PRK combined with CXL in preventing the progression of post-LASIK keratectasia.MethodsIn this prospective,self-controlled study,16 eyes of 14 patients with post-LASIK keratectasia underwent PTK and PRK combined with CXL procedures.None of the 14 patients had keratoconus before LASIK.The main outcomes were measured and recorded at baseline and at months 1,3 and 6 after LASIK.The measured parameters included logarithm of the minimum angle of resolution(LogMAR)of the uncorrected visual acuity(UCVA),LogMAR of the best-corrected visual acuity(BCVA),central corneal thickness(CCT),maximum front keratometry(Kmax)and endothelial cell density(ECD).Data were analyzed using Wilcoxon rank sun test.Results1.LogMAR UCVA improvements were statistically significant(P<0.01)at 1,3,and 6 months postoperatively(0.10 ± 0.12,0.09 ± 0.16 and 0.04 ± 0.15 respectively)compared with preoperatively(0.61 ±0.25).2.Statistically significant(P<0.05)Kmax reduction were observed at 1,3 and 6 months postoperatively.The Kmax was 49.14 ± 4.86D before surgery,and was 47.89±5.31 D,44.08 ±4.88 D and 43.41 ±4.37 D at 1,3,and 6 months after surgery.3.The central corneal thickness was 401.25 ±32.44 and 394.00 ±28.12 at 3 and 6 months after surgery.There was significant difference compared with preoperative(P<0.01).4.There was no statistical significance in changes of LogMAR BCVA or ECD during 6 months of follow-up.ConclusionsPTK+PRK+CXL is effective and safe in treating the keratectasia of post-LASIK.It can improve UCVA and reduce Kmax after surgery.PTK,PRK combined with CXL appeared to halt the progression of post-LASIK keratectasia without apparent complication in our cohort.