The purpose of the present Randomized Clinical Trial (RCT) is to compare the efficacy and safety of transepithelial corneal cross-linking using iontophoresis (T-ionto CL) to treat progressive keratoconus in comparison with standard cross-linking (standard CL).
Keratoconus is a progressive corneal ectatic disease causing visual impairment by inducing irregular astigmatism and corneal opacity. This disorder typically begins during the second decade of life and, in severe forms, may need a corneal transplantation. Corneal cross-linking with riboflavin and UV-A is a procedure intended to halt keratoconus progression. It generates additional chemical bonds between stromal proteins in order to stiffen the corneal tissue. Standard CL includes epithelial removal and stroma soaking with dextran-enriched 0.1% riboflavin solution for 30 minutes before being exposed to ultraviolet-A radiation using a 3mW/cm2 lamp for 30 minutes. Epithelial debridement exposes the cornea to a risk of side effects, such as pain for the first two post-operative days, temporary loss of visual acuity during the first three months, and serious complications, such as infection and stromal opacity due to corneal scarring. Iontophoresis is a non invasive technique in which a weak electric current is used to enhance the penetration of hypotonic 0.1% riboflavin-5-phosphate solution into the corneal stroma through the intact epithelium. After iontophoresis, the corneal tissue is irradiated using a 10 mW/cm2 for 9 minutes (T-ionto CL). From previous experimental work (Lombardo M. et al. JCRS 2014 and JCRS 2015), the investigators provided evidence that T-ionto CL increases the stiffness of human corneas with results almost comparable with standard CL. The new procedure holds the promise to be as effective as the standard procedure while minimizing all the related risks. It is object of the present clinical trial to randomize patients with progressive keratoconus to T-ionto CL and standard CL and compare efficacy and safety of treatments.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
30
The procedure involves a constant current source and two electrodes. The active electrode is a bath tube, which includes a stainless steel grid, placed into the cup at a minimal distance from the cornea. The reservoir is filled with dextran-free, hypotonic riboflavin-5-phosphate solution. The generator applies a constant current of 1mA for a preset period of 5 min. After the riboflavin administration by iontophoresis, the cornea is irradiated using a UVA lamp of 10mW/cm2 for 9 minutes.
In the standard CL, the epithelium is mechanically removed. Then, a solution of riboflavin is instilled each minute for 30 minutes. Corneas are irradiated using a UVA lamp of 3mW/cm2 for 30 minutes.
Fondazione G.B. Bietti, IRCCS
Rome, Italy
K-max
Measuring maximum keratometry (K-max), measured in diopters (D), derived from computerized videokeratography.
Time frame: Changes from baseline in Kmax at 12 months
Corneal Endothelial Cell Density
Endothelial cell density (ECD) will be evaluated using specular microscopy
Time frame: Changes from baseline in ECD at 12 months
Optical Aberrations
Optical aberrations of the eye will be measured using dynamic skyascopy. Corneal wavefront aberration will be measured using Placido disk topographer and Scheimpflug tomographer.
Time frame: Changes from baseline at 12 months.
Visual Acuity
Visual acuity tested using ETDRS
Time frame: Changes from baseline at 12 months.
Contrast Sensitivity
Contrast sensitivity tested using Pelli-Robson chart
Time frame: Changes from baseline at 12 months.
Central Retinal Thickness
Central retinal thickness (1 mm ETDRS map) will be measured before and after CXL procedures
Time frame: Changes from baseline at 12 months.
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.