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Published on: November 12, 2015
Second-Generation ELZA-sub400 Protocol: Individualized High-Fluence Cross-Linking for Ultra-Thin Keratoconus Corneas
Farhad Hafezi1, Rüstü Emre Akcan2, Sabine Kling3
1Center for Applied Biotechnology and Molecular Medicine (F.H., E.A.T.N.), University of Zurich, Switzerland; ELZA Institute (F.H., L.K., M.D., N.H., M.H., E.A.T.N.), Dietikon, Switzerland; Department of Ophthalmology (F.H.), New York University Grossman School of Medicine, New York University, New York, New York, USA; Faculty of Medicine (F.H.), University of Geneva, Geneva, Switzerland; USC Roski Eye Institute, Keck School of Medicine (F.H.), University of Southern California, Los Angeles, California, USA; School of Ophthalmology and Optometry (F.H.), Wenzhou Medical University, Wenzhou, Zhejiang, China.
This study shows that a new corneal cross-linking (CXL) protocol effectively halted ectasia progression in 76% of ultrathin corneas within 12 months. The treatment demonstrated a good safety profile, making it a promising option for managing progressive keratoconus and post-LASIK ectasia.
Area of Science:
- Ophthalmology
- Corneal Ectasia Treatment
- Corneal Cross-Linking (CXL)
Background:
- Corneal ectasia, including progressive keratoconus and post-LASIK ectasia, poses a significant challenge, particularly in ultrathin corneas.
- Standard corneal cross-linking (CXL) protocols may have limitations in treating corneas with a thinnest stromal thickness below 400 µm.
- Developing safe and effective CXL methods for these challenging cases is crucial for preventing further visual deterioration.
Purpose of the Study:
- To evaluate the safety and efficacy of a second-generation individualized corneal cross-linking (CXL) protocol, ELZA-sub400, in ultrathin ectatic corneas.
- To assess the ability of this high-fluence UV-A irradiation protocol to halt ectasia progression.
- To determine the short-term safety profile of the ELZA-sub400 protocol in this patient cohort.
Main Methods:
- A retrospective, single-center study included 29 eyes of 24 patients with progressive keratoconus or post-LASIK ectasia and thinnest stromal thickness <400 µm.
- Epithelial removal, riboflavin soaking, and continuous UV-A irradiation (365 nm) at 3 or 9 mW/cm² were employed, with total fluence titrated up to 10 J/cm².
- Outcomes were assessed up to 12 months, measuring corrected distance visual acuity (CDVA), keratometry (Kmax), stromal thickness, and demarcation line depth using advanced imaging techniques.
Main Results:
- At 12 months, 76% of eyes (22/29) met the non-progression criterion (defined as <1.0 D increase in Kmax).
- The mean change in Kmax was -0.77 ± 5.10 D, indicating no statistically significant progression.
- The demarcation line remained within the stromal layer in all eyes, with no observed deep stromal haze or endothelial decompensation, indicating a favorable safety profile.
Conclusions:
- The second-generation ELZA-sub400 CXL protocol successfully halted ectasia progression in 76% of ultrathin corneas at 12 months.
- The protocol demonstrated an acceptable short-term safety profile, characterized by stromal-confined demarcation lines and absence of endothelial complications.
- While a numerical decline in CDVA was noted, it did not reach statistical significance, warranting further investigation in larger prospective studies.
