Abstract
Purpose :
Blindness caused by corneal opacity is often a result of corneal scarring and vascularisation from infectious diseases, inflammation and corneal trauma. The ‘gold standard’ amniotic membrane (AM) is often applied to the ocular surface as a treatment to induce the healing process and reduce scarring, as it is capable of releasing anti-fibrotic/anti-inflammatory factors. The reproducibility and repeatability however of the clinical effects of the AM are limited due to their biological variability. Consequently a plethora of treatment strategies have previously been investigated however very few have replaced the AM. We have developed a transparent gel dressing that can be applied as an eye drop to the ocular surface that is capable of occluding the wound with sufficient lubrication as well as delivering the anti-scarring agent, decorin, in a sustained manner to the cornea.
Methods :
Gel dressings were produced by heating the hydrocolloid to melting point and by controlled temperature processing, reduced the temperature to form a gel. In vitro decorin release studies from the gel dressing were carried out using an ELISA assay. The gel was applied to the corneal surface of rat eyes and thickness was measured using OCT for 2h. The decorin containing gel was applied as a single dose to a 2mm ex-vivo corneal ulcer to observe wound healing and re-epithelialisation.
Results :
The gels containing the anti-scarring molecule released a sustained dose of decorin over 4h. Thickening of the gel occurred immediately in vivo when dropped on the surface of a rat eye. The gel evenly covered the ocular surface and remained for upto 2h whereas a PBS drop was not visible after 30min. Re-epithelialisation occurred within 48h in the presence the decorin gel in the ex-vivo models when compared to a decorin-PBS drop which showed limited wound closure over the same time. Collagen type IV deposition was significantly reduced in 14 days in the presence of the decorin gel, indicative of reduced fibrosis on the corneal surface.
Conclusions :
We have successfully demonstrated a gel ‘eye drop’ therapy for the attenuation of corneal scarring. The properties of the gel allow a sustained, effective dose of decorin to be released onto the corneal surface over 4h after application and the formation of a gel on the ocular surface provides a protective transparent dressing promoting re-epithelialisation and reducing fibrosis in ocular surface disease.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.