Purpose:The aim of this study was to introduce a revised tissue-saving technique for combined topography-guided photorefractive keratectomy (PRK) and cross-linking for keratoconus (KC) treatment and to evaluate its efficacy, safety, and stability.Methods:This retrospective, noncontrolled study was performed at Maadi Eye Subspecialty Center and Eye Care Center, Cairo, Egypt. The technique was performed on virgin keratoconic corneas with 3 different morphological patterns of ectasia. It involves performing topography-guided PRK before epithelial removal, followed by customized phototherapeutic keratectomy (PTK) that is tailored to each cornea after studying the treatment profile on the laser treatment screen. The electronic medical records were explored for preoperative and postoperative data, including subjective refraction and topographic data (using Sirius topographer).Results:The study was conducted on 123 eyes of 93 patients with a mean age of 27.98 years ±6.06. The follow-up ranged from 6 to 36 months (mean ± SD of 16.2 months ±10.4). The results showed statistically nonsignificant differences among the 3 ectasia subgroups in treatment spherical equivalent, treatment maximum depth, thickness of removed epithelium, and thinnest residual stromal bed. There were statistically significant differences in almost all values between the preoperative and postoperative data, with significant postoperative patients' improvement (P value <0.001). The subgroups' results were almost the same as the whole cohort's results. The safety and efficacy indices of the performed procedure showed remarkably high values (1.48 ± 0.21 and 0.87 ± 0.40, respectively).Conclusions:This revised protocol for KC management maximally preserves stromal tissue with proven efficacy, safety, and stability.

Purpose To compare between two accelerated corneal cross-linking (A-CXL) protocols in the management of keratoconus (KC) as regard to the extent of corneal treatment. Methods This retrospective, comparative study included patients having mild to moderate, progressive KC. The study population was divided into two groups; group 1 enrolled 103 eyes of 62 patients who received pulsed light A-CXL (pl-CXL) at a power of 30 mW/cm 2 with an irradiation time of 4 minutes, while group 2 comprised 87 eyes of 51 patients who received continuous light A-CXL (cl-CXL) at a power of 12 mW/cm 2 with an irradiation time of 10 minutes. Recordings of the central and peripheral demarcation line depths (DD), and the maximum (DDmax) and minimum (DDmin) DD, using anterior segment optical coherence tomography, were compared between the two studied groups one month after the treatment protocol. Treatment stability was also evaluated pre and postoperatively (one year following surgery) by comparing the refractive and keratometric outcomes in both groups. Results The differences between the preoperative corneal thickness (minimum and central) and the epithelial thickness measurements between both groups were not statistically significant. Although group 1 had slightly larger central DD (223.4 ± 62.3 um), DDmax (240.4 ± 61.8 um), and DDmin (201 ± 54 um) than those of group 2 (221.8 ± 37 um, 229.1 ± 38.4 um, and 212 ± 37.2 um, respectively), the differences between both groups’ measurements were not statistically significant. Also, the two groups showed statistically insignificant differences regarding the subjective refraction and the average and maximum keratometry pre and postoperatively, denoting visual, refractive, and keratometric stability in both groups. Conclusion Longer duration cl-CXL seems to be as effective as pl-CXL regarding both postoperative stability and the extent of corneal tissue penetration by the ultraviolet treatment.

Purpose The aim of the present study was to validate the use of a novel technique that can improve the efficacy of corneal cross-linking (CXL) in cases with post LASIK ectasia. Methods This is a retrospective, comparative study that was conducted on patients who sought medical advice at Ain Shams University Hospitals and Maadi Eye Subspeciality Center, Cairo, Egypt. It included two groups of patients with post LASIK ectasia. Group 1 included patients who performed our proposed protocol (topo-guided PRK, followed by customized phototherapeutic keratectomy “PTK” to transmit the laser treatment to the corneal stroma, then CXL). For group 2, accelerated CXL was performed. Subjective refraction and relevant topographic/tomographic parameters (Sirius topographer) compared between the two groups. Recorded follow-ups included the 2 to 3-month follow-up visit and the last visit (mean ± SD of 17.2 months ± 10.2). Results Patients of group 1 (22 eyes of 22 patients) experienced significant improvements in most of the evaluated parameters at the 2- to 3-month follow-up visit and showed stability of the ectatic condition at the last follow-up visit, whereas patients of group 2 (10 eyes of 10 patients) showed stability of their ectatic condition at the 2- to 3-month follow-up visit, and one patient developed ectasia progression at the last follow-up visit. Conclusion The present study validates the use of our novel protocol in cases having post LASIK ectasia with proven efficacy, safety, and stability, providing regularization for the corneal surface while simultaneously avoiding the unnecessary loss of cross-linking effect within the LASIK flap that no longer shares in the corneal biomechanical strength.

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