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Carmen Martinez-Garcia, Irene Kochevar, Patricia Gallego-Muñoz, Lucia Ibares-Frias, Elvira Lorenzo, Susana Marcos; Corneal Wound Repair after Rose Bengal and Green Light Cross-linking: Clinical and Histological Study. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5280. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Conventional corneal cross-linking is an intervention that has been demonstrated to be effective in halting disease progression in ectatic pathologies as keratoconus. This procedure utilizes riboflavin and ultraviolet-A. However, it has some drawbacks is a long procedure time, and limitation to only treating corneas greater than 400 μm thick. For these reason, another techniques are being developed such as collagen cross-linking that uses green light to activate rose bengal (RB).Our aim was to evaluate corneal wound healing after treatment with this new collagen cross-linking protocol using rose bengal dye and green light
One cornea of 20 New Zealand rabbits was de-epithelized (DE) in an 8 mm-diameter circle and, in another group (n=25), the de-epithelialized corneas were then stained with 0.1% rose bengal for 2 minutes and exposed to green light (532 nm) for 7 minutes (RGX). The contralateral eyes of all rabbits received no treatment and served as controls. The animals were followed by clinical observations including fluorescein staining, slit lamp exam and pachymetry. After euthanasia at 2, 30 and 60 days, the healing events were analyzed. Analyses of cell death (by TUNEL), cell proliferation (by BrdU) and cell differentiation to myofibroblast (by αSMA) were carried out. In addition, the loss of keratocytes and the repopulation of the corneal stroma were quantified in hematoxylin-eosin stained sections.
Wound closure was slower after RGX (4.4 days) than after DE (3.3 days). Edema was greater in DE than RGX eyes, maximal at 2 days and decreased at day 4 in both treated groups. Cell death was restricted to the anterior central cornea stroma, where the cellular decrease in RGX corneas was not significantly different from DE eyes. Cell proliferation in the epithelium and stroma was visible at 2 days. In both DE and RGX corneas recovery of the epithelium was complete at day 30, but cell repopulation of the stroma was not complete at 60 days.
The healing response in corneas after photo-crosslinking with RGX is very similar to that observed after de-epithelialization alone suggesting that, along with its short treatment time and limited effect on keratocytes, RGX has high potential for clinical cornea stiffening.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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