Randomized bilateral study of trans-epithelial corneal cross-linking
Research type
Research Study
Full title
A Randomized, Bilateral, Controlled, Prospective Study to Investigate the efficacy of Trans-epithelial Riboflavin/Ultraviolet A Corneal Collagen Cross-linking using Iontophoresis to halt the progression of Keratoconus
IRAS ID
133912
Contact name
David P S O'Brart
Contact email
Sponsor organisation
R&D Department, Guy's and St. Thomas' NHS Foundation Trust
ISRCTN Number
ISRCTN04451470
Research summary
Keratoconus is characterized by central corneal thinning and ectasia (bulging). The irregular corneal shape results in reduced vision. The condition is bilateral, often asymmetrical. Onset is usually around puberty with progression until the third or fourth decade. It affects approximately 1 in 1750 individuals, occurring in all ethnic groups and equally affects males and females. Quality of life analysis indicates that its magnitude of public health impact is disproportionate to its prevalence, with scores similar to severe macular degeneration.
Riboflavin (vitamin B2)/ultraviolet A (UVA) (370nm) corneal collagen cross-linkage (CXL) is the first treatment modality which appears to stabilize the cornea and halt the progression of keratoconus. It involves removing the central corneal skin (epithelium), applying vitamin B2 drops, which soak into the substance of the cornea (its stroma), and then shining ultraviolet light at 370nm onto the cornea. This has been shown to increase the strength of the cornea by cross-linking the molecules within it. In clinical studies it has been shown to halt the progression of keratoconus with up to 6 years follow-up as well as improve the overall corneal shape in the majority of eyes. Complications are few but removal of the epithelium results in significant post-operative pain as well as increasing the rare risks of post-operative infection and scarring.
Riboflavin is poorly lipid soluble so it does not penetrate the intact epithelium well and reach the underlying corneal tissue. However, Riboflavin is a small molecule which is negatively charged and Iontophoresis has been shown to be effective in allowing Riboflavin to enter the corneal stroma without the need to remove the corneal epithelium, thereby speeding post-operative recovery, reducing pain and risk of infection and scarring. The aim of this present study is to compare the efficacy of an epithelium-on (trans-epithelial)technique with the standard epithelium off procedure.REC name
London - Bromley Research Ethics Committee
REC reference
13/LO/1895
Date of REC Opinion
26 Feb 2014
REC opinion
Further Information Favourable Opinion