Journal Club Corneal Intrastromal Ring Segmentspptx

Journal Club discussing Intracorneal Allogenic Ring Segments for Keratoconus

1. JOURNAL CLUB - CORNEA Dr. Zaid Azhar SIH

2. Senay Asik Nacaroglu, Elif Ceren Yesilkaya , Fatma Feyza Nur Keskin Perk, Cafer Tanriverdi, Suphi Taneri and Aylin Kilic Efficacy and Safety of Intracorneal Allogenic Ring Segment Implantation in Keratoconus: 1-Year Results

3. Faculty of Medicine of Istanbul Medipol University, Istanbul, Turkey Duration - February 2020 and August 2021 Submitted - 18 August 2022   Published 16 June 2023 Journal Location / Time Aim To evaluate the efficacy and safety of corneal allogenic intrastromal ring segments implantations in keratoconus subjects. Study Details Eye (2023) 37:3807–3812;   Type Retrospective observational study DOI 10.1038/s41433-023-02618-5

4. Abstract Objective: To evaluate safety and efficacy of corneal allogenic intrastromal ring segments (CAIRS) in keratoconus. Design: Retrospective, nonrandomized case series (65 eyes, 49 patients). Results: UCVA improved 0.91→0.40 logMAR CDVA improved 0.87→0.27 logMAR Mean keratometry 49.23→45.63 D Minimal complications: 1 dislocation, 5 deposits. Conclusion: CAIRS provides safe and effective alternative to synthetic ICRS.

5. Introduction Keratoconus: progressive thinning and ectasia causing visual impairment. Early stage: spectacles/contact lenses. Advanced stage: keratoplasty (PKP/DALK). Synthetic ICRS effective but can cause complications. CAIRS (Jacob, 2018): allogenic ring segments offer higher biocompatibility. Aim: Evaluate safety and efficacy of sterile allogenic corneal ring segments ( KeraNatural ®).

6. Sampling Age ≥18 years Diagnosed keratoconus CDVA <0.5 Snellen Contact lens intolerance/refusal Prior corneal crosslinking (CXL) Previous ocular surgery Post-LASIK ectasia Central/paracentral scarring Other corneal lesions or viral keratitis Central corneal thickness <400 µm Inclusion Criteria Exclusion Criteria

7. Materials and Methods Design: Retrospective observational study at Istanbul Medipol University (Feb 2020–Aug 2021). Implant: KeraNatural ® (Lions VisionGift , USA). Follow-up: Preop, 1, 3, 6, 12 months. Outcome Measures: UCVA, CDVA, refraction, keratometry, pachymetry, corneal elevation.

8. CXL Technique Technique: Accelerated conventional CXL at 10 mW /cm² for 9 minutes (total energy 5.4 J/cm²). Anesthesia & Epithelium Removal: Topical 0.5% proparacaine applied. 8 mm central epithelium removed with blunt spatula. Riboflavin Application: Dextran–riboflavin (0.1%) solution instilled every 2 minutes for 30 minutes. If corneal thickness <400 µm → switched to hypotonic riboflavin to swell cornea. Irradiation: UVA exposure (9–10 mW /cm²) using Peschke Meditrade device. Progression Definition: Keratoconus progression = increase in Kmax >1.0 D within the previous 12 months .

9. Surgical Technique Topical anesthesia Femtosecond laser channel (4–7.5 mm diameter, 35% depth) Single ring segment (160° arc) No sutures Post-op care: Moxifloxacin 0.5% + Dexamethasone 0.1% drops × 2 weeks, tapered over 6 weeks.

10. Surgical Technique

11. Statistical Analysis Statistical analysis was carried out in the SPSS version 21.0. Power analysis test was performed to determine the optimal sample size for the study. The Kolmogorov–Smirnov test was performed to assess normality Repeated measures ANOVA was used when the assumption of normal distribution was met. Friedman’s test was used when normal distribution was not obtained. Pearson’s correlation coefficient was employed for correlation. P < 0.05 were accepted as statistically significant.

12. Results – Demographics 65 eyes, 49 patients (38M, 11F) Mean age: 29.5 ± 7.3 years (20–52) Interval between CXL & CAIRS: 61 ± 42 months 16 bilateral cases No intraoperative complications

13. Results – Visual Outcomes Parameter | Pre-op | 12 mo | p-value UCVA ( logMAR ): 0.91 → 0.36 | <0.01 CDVA ( logMAR ): 0.87 → 0.36 | <0.01 Spherical Eq (D): −8.82 → −2.32 | <0.01 Kaverage (D): 49.23 → 45.23 | <0.01 91.7% gained ≥1 line UCVA; 100% gained ≥1 line CDVA.

14. Visual Outcomes - Graphical Summary

15. Keratometric Changes Over Time

16. Results – Tomographic Changes Significant reduction: K1, K2, Kmax , Kaverage , anterior & posterior elevations. Central corneal thickness unchanged. Yellow-white stromal deposits in 7.6% (no visual effect). No progression within 12 months.

17. Discussion Early and sustained visual improvement. Advantages over synthetic ICRS: - Biocompatible & shallower depth (35%) - Better surface regularization - Minimal complications No correlation between elevation changes and vision improvement.

18. Study Analysis Similar surgery techniques for all cases. Data displayed in legible format. Small sample size (n=65) 12-month follow-up only No control/comparison group Longer studies needed for progression evaluation. Strengths Limitations

19. Conclusion Intracorneal allogenic ring segment implantation (CAIRS): Safe and effective Improves UCVA, CDVA, keratometry Biocompatible alternative to synthetic rings Promising short-term stability and outcomes.