Corneal cross-linking and keratoconus The change in treatment paradigm of keratoconus.

摘要

Keratoconus is an eye condition in which the cornea develops a conical shape due to weakening and thinning of the stromal connective tissue; it affects mostly young people in their teens and twenties and can lead to severe visual impairment. Rigid gas permeable contact lenses are the mainstay of correction of this disease; corneal transplants are performed for advanced cases.;In the past decade irradiation of the cornea with ultraviolet A-light after riboflavin instillation has been developed to "cross-link" the connective tissue and thereby stiffen the cornea. This procedure leads to stabilisation of keratoconus, thereby avoiding visual impairment. The aim of this thesis is to investigate how and to what extent corneal cross-linking (CXL) has changed the treatment paradigm for keratoconus, based on a scientifically validated analysis of the technique.;Initially the author studied standard CXL with epithelial removal: this technique proved effective at stabilising the disease. Complications in 4 out of 37 treated eyes led to corneal scarring and decreased visual acuity. Therefore a transepithelial CXL alternative has been developed, in which the epithelium, the protective layer of the cornea, does not have to be removed: the stabilising effect is less pronounced but the treatment has no side-effects.;These developments have led internationally to a hugely increased interest in keratoconus, which as such may be of great benefit to the patients. There is, however, a major drawback in this recent (r)evolution in the therapeutic approach of keratoconus: information on CXL is disseminated on the internet without scientific validation and CXL has rapidly become a mainstream treatment in many private ophthalmology practices. Costly surgical solutions for the patient seem to replace contact lens correction as a first line of treatment in refractive surgery practices. The patient who is getting his information on the internet, mostly from non peer reviewed sources, is confused by all the possibilities presented. For all these reasons we deem it important for academic centres to participate in these valuable evolutions while at the same time looking critically at the results of treatments in well-informed and consenting patients.