1. 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

2. 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

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. 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

10. 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

11. 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

12. 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