1：Experimental Design and Method Selection:

A prospective case series of 38 eyes of 26 patients with keratoconus had implantation of the 355-degree ICR keraring after tunnel creation with a femtosecond laser. The uncorrected visual acuities (UCVA) and best-corrected visual acuities (BCVA), sphere, cylinder, and manifest refraction spherical equivalent (SE), and mean keratometry (K), K max, and K min were evaluated preoperatively and 3, 6, 12, 24, and 36 months postoperatively, and all complications were reported.

2：Sample Selection and Data Sources:

38 eyes of 26 patients with mean age 25.92 ± 5.44 years were enrolled in the study, 11 were males (42.3%).

3：92 ± 44 years were enrolled in the study, 11 were males (3%). List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Femtosecond laser (iFS Advanced Femtosecond Laser, Abbott, USA), 355-degree Keraring (Mediphacos Inc., Belo Horizonte, Brazil), Pentacam rotating Scheimp?ug device (OCULUS Optikgerate GmbH, Wetzlar, Germany).

4：Experimental Procedures and Operational Workflow:

The procedure was performed under topical anesthesia using benoxinate hydrochloride followed by sterilization using Betadine (5% povidine iodine), and a sterile plastic sterile was applied to draw away the lashes, and then the speculum was used to open the eye. Procedures started by marking the corneal center when the patient was ?xating at the ?xating light, then followed by application of the suction ring onto the cornea with great care of corneal centralization within the suction ring. The corneal tunnel was created using the femtosecond laser (iFS Advanced Femtosecond Laser, Abbott, USA), with a power of 5 mJ. Passing a spatula was performed through the limbs of the tunnel to check its patency. The 355-degree Keraring (Mediphacos Inc., Belo Horizonte, Brazil) segments were implanted carefully.

5：Data Analysis Methods:

Data were analyzed using SPSS computer program version 22.0. Quantitative data were expressed as means ± standard deviation, median, and range. Qualitative data were expressed as number and percentage. The data were tested for normality using the Shapiro–Wilk test. The non-parametric Wilcoxon signed-rank test was used because the data were not normally distributed. A 5% level was chosen as a level of signi?cance in all statistical tests used in the study.