Published date: Jul 29 2020

Journal Title: Journal of Ophthalmic and Vision Research

Issue title: July–September 2020, Volume 15, Issue 3

Pages: 289 – 298

DOI: 10.18502/jovr.v15i3.7447

Aysun Sanal Doganasanaldogan@gmail.comDepartment of Ophthalmology, Saglik Bilimleri University, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey

Canan GurdaDepartment of Ophthalmology, Saglik Bilimleri University, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey

Sinan CaliskanDepartment of Ophthalmology, Saglik Bilimleri University, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey

Evrim OnderDepartment of Pathology, Saglik Bilimleri University, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey

Figen KaymazDepartment of Histology and Embryology, Hacettepe University, School of Medicine, Ankara, Turkey

Elif BilgicDepartment of Histology and Embryology, Hacettepe University, School of Medicine, Ankara, Turkey

Purpose: Ozone is a trioxygen molecule that spontaneously degrades into oxygen and oxygen free radicals. This study was designed to assess the effects of topical ozone application on outcomes after corneal collagen cross-linking (CXL).

Methods: Enucleated fresh cadaver yearling sheep eyes (n = 28) were divided into five groups: control (C, n = 6), sham (S, n = 6), ozone only (Z, n = 6), CXL only (X, n = 5), and Ozone + CXL (ZX, n = 5). In all groups, except C, the epithelial layer was removed. In group Z, 20 μg/mL liquid ozone was topically applied. In group X, CXL was performed in the accelerated pulse mode. In group ZX, both CXL and ozone were applied. Post-interventional oxygen levels were determined and corneal confocal microscopy and optical coherence tomography were performed. Corneas were evaluated using light and electron microscopy.

Results: Pre-interventional central corneal thickness (CCT) was highest in the control group and considerably similar in the remaining groups (P = 0.006). Pre- and post-interventional CCT were significantly different in the ozonated groups (Z and ZX) (P = 0.028; P = 0.043). Demarcation line depths were similar in groups Z, X, and ZX (P = 0.343). Increased stromal tissue reflectivity was observed in groups Z, X, and ZX. Oxygen levels were higher in the ozonated groups (Z and ZX) (P = 0.006), and caspase activity was higher in the CXL groups (X and ZX) (P = 0.028) as compared to the other groups. Group ZX showed tighter, more regular, and parallel fibrils.

Conclusion: Ozone increases corneal stromal oxygenation which can probably augment the effect of CXL. Future studies should investigate the safety and feasibility of ozone application during CXL.

Keywords: Ozone, Corneal Collagen Cross-linking, Corneal Confocal Microscopy, Corneal Oxygen, Experimental

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