Keratoconus and corneal collagen cross-linking

Abstract

Keratoconus, a degenerative disorder of the cornea, causes significant visual distortion and photophobia. Diagnosed in early life, it has a considerable influence on the patient's daily activities and visual needs. A study of the rural population in Central India gave a prevalence of 2.3% +/- 0.2% among those aged 30 years and above.[1] The conventional treatment of keratoconus has been the fitting of contact lenses and surgical treatments such as keratoplasty and intrastromal corneal ring segments. In spite of these therapies, the condition can be progressive and hence distressing to the patient. Lending hope is a parasurgical treatment that was developed in 1998 in Germany called “Corneal Collagen Cross-linking.”[2] The ability of adjacent collagen fibrils to form strong chemical bonds is called “cross-linking.” This helps to halt the progression of ectasia by strengthening the cornea. Glycation and oxidation are some of the pathways that are essential to this process of cross-linking. After adequate riboflavin absorption, the patient is subjected to UV irradiance (typically 365–370 μm) with the resultant corneas being stiffer and more resistant to enzymatic digestion. This special issue will cover all aspects of keratoconus and cornea collagen cross-linking. It is an honor that “father” of crossing-linking Prof. Dr. Theo Seiler has written the editorial. Basic science researchers have discussed the genetic, proteomic, and biomechanical perspectives. This will allow us to better understand the pathophysiology of keratoconus. Imaging investigations play an important role in both the diagnosis and follow up. Dr. Michael Belin has extensively covered Scheimpflug Imaging for Keratoconus and ectatic disease. A stepwise approach to the management of keratoconus is of utmost importance. In the current issue, all the available modalities of treatment are deliberated upon with special emphasis on cornea collagen cross-linking. The principles behind cross-linking along with the newer protocols are described by Michael Mrochen and Arthur B. Cummings. George D. Kymionis has given an overview of the management of pediatric keratoconus. The current indications for combined very high-fluence collagen crosslinking and laser in situ keratomileusis surgery have been listed by Prof. Anastasios Kanellopoulos. Recent advances in the surgical management of keratoconus have also been discussed in depth. With the available armamentarium of therapies for keratoconus we should be able to provide better visual rehabilitation to patients afflicted with this condition. Combining early diagnosis and treatment with a preventive approach will help to reduce the visual morbidity caused by keratoconus. This issue was made possible due to the efforts of our dynamic editor Dr. S. Natarajan and his team. We were able to put together a group of authors who are doing extensive work in the fields of keratoconus and collagen cross-linking. I hope that the readers find this special issue as intellectually stimulating as we did making it.