Aim To evaluate predictability, safety, efficacy, and visual outcome of StreamLight. ™ (SL.), the newly released single-step transepithelial photorefractive keratectomy platform by Alcon WaveLight™ (WL). Methods In this prospective cohort study, photorefractive keratectomy (PRK) was conducted on 500 eyes of 250 patients seeking myopic refractive vision correction. The new single-step transepithelial PRK method was applied, using the SL. platform installed in the WL. Ex 500 excimer laser machine. Patients were followed up to monitor intensity and duration of postoperative pain, as well as speed of epithelial healing in the early post-operative period and visual acuity, postoperative refraction and development of postoperative haze for one year post-operatively. Results Average pain duration was 1.5 days, and the mean pain intensity score on a scale of 0–10 was 3.74 + 1.51. Mean postoperative spherical equivalence was 0.01 ± 0.38 D, and the final postoperative uncorrected distance visual acuity (UCDVA) was 20/20 in 98% of eyes included in this study. None of the eyes lost more than one Snellen chart line or developed visually significant postoperative haze during the follow-up period. Conclusion The new SL. platform for transepithelial PRK is a safe, accurate platform, offering an easier early post-operative recovery, with no compromise in final visual outcome.

Purpose To assess the stability, safety, predictability, and efficacy of topography-guided myopic Femto-LASIK with two different treatment protocols. Setting Ebsar Eye center, Benha, Qalyopia, Egypt. Design Single-center, retrospective, COHORT control study. Methods A total of 330 eyes enrolled in the study in group A and 322 eyes enrolled in group B underwent uncomplicated primary bilateral topography-guided Femto-LASIK. Group A was treated with the subjective clinical refraction; however, group B was treated with the modified refraction according to ALCON protocol. Results The mean preoperative refractive spherical equivalent (MRSE) was −4.85±1.90D and −5.0±1.93D in group A and B, respectively (P = 0.86), and a cylinder of −0.95±0.80 D and −0.92±0.81D, respectively. At the 12 months’ postoperatively, the residual manifest SE within ± 0.5D was achieved by 82.86% of eyes in group A compared to 83.93% in group B. Of eyes, 92.06% had ≤0.5 astigmatism dioptre, while 100% of eyes had ≤1.0 astigmatism dioptre in group A (315 eyes); however, 91.80% of eyes had ≤0.5 astigmatism dioptre, while 100% of eyes had ≤1.0 astigmatism dioptre in group B. Conclusion Topographic modification of the magnitude and axis of astigmatism treated using ALCON protocol when different from the clinical refraction may offer good refractive outcomes when we apply the Alcon precalculation considerations.

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METHODS:In this retrospective cohort study, we analyzed the tomography of 611 eyes of 4 groups of patients using manual interpretation and Hamed's Interpreter as well. RESULTS:There is a statistically significant difference between group 2 and group 1 regarding the inter eye differences in thinnest location (P-value 0.021) and also manifest refraction spherical equivalent (P-value 0.011). The mean of both was significantly high in group 1 (patients with postoperative ectasia) 17.0 ± 7.87 and -5.56 ± 2.16 respectively. There is a statistically significant difference between group 3 and group 1 regarding percent tissue altered (P-value <0.001) and residual stromal thickness (P-value <0.001). The mean of percent tissue altered was significantly higher among patients who had post-laser keratorefractive surgery ectasia group (37.23 ± 5.18) while the mean of residual stromal thickness was significantly low among this group (328.25 ± 41.6). In respect to group 4, the mean of the Inter eye score was 3.38 ± 1.04, and the mean of relative thickness map was -9.2 ± 0.596. The shape of the thickness profile map curve was a quick slope in 61.5% of eyes and normal in 38.5% of eyes in group 4. Some ectasia risk factors were missed during manual interpretation of topography that led to post LVC ectasia. CONCLUSIONS:Developing an artificial intelligence system that can interpret corneal tomography will alleviate the human errors of manual interpretation. INTRODUCTION:Detection of corneas with ectasia possibility comprises a cornerstone of preoperative screening for corneal laser vision correction. There are many investigation options like abnormal anterior and posterior corneal curvature 1 , localized corneal thinning 2 , focally decreased corneal epithelial thickness, 3 and corneal biomechanical instability. 4,5 However, no method gives absolute sensitivity and specificity, we still need to refine the existing diagnostic tools.Inter-eye asymmetry is a famous feature of keratoconus. 6,7 research studies have investigated the inter-eye asymmetry in keratoconus patients, 7-10 because normal corneas are almost symmetric. [11][12][13][14] The investigators demonstrate the significant overlap between healthy corneas and corneas with subclinical keratoconus, 1,15 also they demonstrate the increasing sensitivity by using artificial intelligence in interpreting and Using artificial intelligence in the interpretation of corneal topography for laser vision correction. EJO(MOC) 2021;4:176-188