Crosslinking with Simultaneous Implantation of Intrastromal Corneal Ring Segments in Keratoconus: Safe and Efficacy Author: Luiz Antonio de Brito Martins MD Co-authors: Leon Grupenmacher MD, Luciene Barbosa de Souza MD, Arnaldo Bordon MD The authors have no financial interest in the subject matter of this poster

Purpose Intrastromal corneal rings implantation as well as corneal collagen crosslinking are first line therapies in selected keratoconus cases and decrease corneal transplantation need. To evaluate the ocular and corneal impact of combined and simultaneous intrastromal corneal rings implantation and corneal collagen crosslinking for keratoconus Evaluate efficacy and safety of the procedure

Methods Prospective and randomized clinical trial Patients with keratoconus aged 15 to 30 years Keratoconus up to 58D Pachimetry minimum of 400µm. The two eyes of the Patients were randomized in two groups Group I - riboflavin and UV-A corneal crosslinking Group II - (control group) was treated with BSS (Balanced Saline Solution) and UV-A corneal crosslinking All patients had the two eyes treated.

Methods Patients were assessed before surgery and 1, 3, 6, 9 and 12 months after surgery. Evaluation included complete ophthalmologic exam (visual acuity with and without correction, near visual acuity , biomicroscopy, applanation tonometry, fundoscopy), corneal topography, specular microscopy and retinal OCT.

Methods Preparation for surgery was performed with 3 drops of 2% pilocarpine, proximetacaine 0,5% and xylocaine gel Corneal optical center was marked A femtosecond laser was used to create the`ring tunnel (IntraLase®) Tunnel depth was set at 80% of the thinnest corneal thickness at 5 mm diameter and the cut was set at the maximum K on topography The corneal rings vary accordingly to patient’s refraction as well as corneal topography and pachymetry.

Methods After implantation of corneal rings, 1 drop of proximetacaine 0,5% was instilled followed by 8-mm-diameter corneal deepithelization (horizontal and vertical cuts). Few epithelium islands (< 0.5 mm) remained. Riboflavin (group I) or BSS (group II) was instilled every 5 minutes during 30 minutes. Corneal irradiation with UV-A 3mW/cm3 was performed for 30 minutes at 45 mm from the cornea.

Methods Instillation of riboflavin or BSS every 5 minutes continued during irradiation After the procedure, the eye was dressed with a therapeutic contact lens and one drop of topical antibiotic (4th generation quinolone) All patients used topical corticosteroid (prednisolone 1%) 6 times a day for 14 days, Moxifloxacin 6 times a day for 7 days and ketorolac tromethamine 3 times a day for 7 days.

Results No retinal lesion in any group was found Corneal haze were found in the two groups, but in none lost line of visual acuity The analisis of the variables probabilistic distribution was made by the Shapiro-Wilk Test Groups comparison to free pattern: Mann-Witney test Times comparison to relative pattern: Friedman test Differences were considered significant if p <0.05.

Results According to Friedman test, uncorrected visual acuity and BCVA had statistical change (were improved) during observation period in both groups. According to Mann-Whitney test, no statistic difference was observed in uncorrected visual acuity and BCVA

Results According to Friedman test, myopia was reduced in group Riboflavin+ring, and in control group it reduced in the beginning and increased six months later According to Mann-Whitney test, there wasn’t statistic difference in myopia and astigmatism in both groups

Results According to Friedman test, flattest axis in topography changed statistically in both groups, but no evidence of statistical change was found in the steepest axis According to Mann-Whitney test, there wasn’t evidence of statistical change in dynamic refraction of both groups

Conclusions Crosslinking with Simultaneous Implantation of Intrastromal Corneal Ring Segments is a good option to treat patients with Keratoconus The Riboflavin group treatment had better stability in myopia than the BSS group A long and a larger study must be done, to confirm the conclusion