• Visual and Refractive Outcomes and Tomographic Changes of One Segment Femtolaser Assisted ICRS Implantation Based on Severity of Kcn. Description: Purpose: To assess the visual and refractive outcomes and tomographic changes after femtosecond laser-assisted implantation of a single-segment intrastromal corneal ring (ICRS; Intacs® SK) in the early stages of Keratoconus and pellucid marginal degeneration Setting: Eye Research Center, The Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences and Iranian Eye Clinic, Tehran, Iran Design: Prospective interventional case series Methods: One segment Intacs SK ICRS was inserted using a femtosecond laser into eyes with stage I–II Keratoconous. Visual and refractive outcomes and corneal tomography changes were analyzed 1 week, 2 months and 6 months postoperatively. Results: The study evaluated 155 eyes of 123 patients (mean age: 31.3 years). At six months post-operation, the spherical equivalent, mean sphere, and mean cylinder were decreased by 0.97, 1.22, and 1.29 diopters (D), respectively. The mean preoperative uncorrected (UCVA) and distance corrected visual acuity (DCVA) increased from 0.78 ± 0.20 to 0.39 ± 0.21 and from 0.45 ± 0.18 to 0.18 ± 0.14 LogMAR (P < 0.001), respectively. Steep and Flat Keratometry, Mean K and anterior and posterior best fit sphere decreased significantly (P < 0.001). Among all eyes, 94.0% gained one or more lines of DCVA. Mean internal anterior chamber depth decreased from 3.21 ± 0.33 to 3.12 ± 0.33 mm (P = 0.001), and mean irregularity in the 3‐mm zone decreased from 4.74± 1.68 to 3.89 ± 1.24 (P <0.000). Conclusion: Implantation of one segment Intacs SK is safe and effective to treat Keratoconus, especially in stage I-II, leading to significant improvement in UCVA, DCVA, and refractive error. Subspecialty: Refractive Management / Intervention Level: Advanced Uploaded By: Seyed Javad Hashemian