Did Collagen Cross-Linking Reduce the Requirement for Corneal Transplantation in Keratoconus? The Canadian Experience

Abstract

Purpose: To investigate the relationship between corneal collagen cross-linking (CXL) and the number of corneal transplants required for the treatment of keratoconus (KCN) in 2 major Canadian provinces. Methods: This is a retrospective review of all corneal transplantation performed in Ontario and British Columbia over an 18-year period (1998–2016). Data were collected at the Eye Bank of Canada—Ontario/British Columbia Divisions. The primary outcome was to determine the change in proportion and absolute number of corneal transplants required for treatment of KCN since the introduction of CXL in Canada in 2008. Results: A total of 31,943 grafts were included. Overall, the mean age of participants was 39.3 ± 2.2 years, with our cohort being composed of 28% of women and 72% of men. The results showed a significant decrease in the proportion of total transplants required for KCN between 1998 and 2016 [1998–2008 (pre-CXL), range: 14.77%–12.63%; 2009–2016 (post-CXL), range: 12.98%–5.50%, P < 0.001]. However, there was no change in the absolute number of grafts performed for KCN over this time (pre-CXL: 179 ± 26 grafts; post-CXL: 198 ± 27 grafts; P = 0.5), whereas the total number of grafts (pre-CXL: 1318 ± 183 grafts; post-CXL: 2181 ± 404; P < 0.001) and endothelial keratoplasties (pre-CXL: 59 ± 108; post-CXL: 966 ± 431 grafts; P < 0.001) increased significantly. In addition, there were no changes in penetrating keratoplasty/deep anterior lamellar keratoplasty (DALK) performed for indications other than KCN (pre-CXL: 1080 ± 157; post-CXL: 1017 ± 92; P > 0.5). Conclusions: Although there has been a significant decrease in the proportion of corneal graft rates for KCN since the introduction of CXL as a factor of all transplants performed for all indications, this result is most likely because of an increase in endothelial keratoplasties rather than decreased transplants performed for definitive treatment.

Changing Trends in Corneal Transplantation in Aotearoa/New Zealand, 1991 to 2020: Effects of Population Growth, Cataract Surgery, Endothelial Keratoplasty, and Corneal Cross-Linking for Keratoconus

“…A Canadian study found a significant decrease in the proportion of total corneal transplants performed for keratoconus but no change in the absolute numbers of grafts performed for keratoconus, and therefore, was believed to represent an increasing demand for endothelial keratoplasty rather than a decrease in requirement for keratoconus 25 ; however, this study did not normalize data to account for population growth. Normalizing the number of transplants per year and per population in NZ and performing piecewise analysis suggest that we are beginning to see the beneficial effects of CXL on keratoconus-related transplantation.…”

Dramatic Reduction in Corneal Transplants for Keratoconus 15 Years After the Introduction of Corneal Collagen Crosslinking

“…Although other studies have reported a significant decrease in the proportion of corneal transplants for KC, this was because of an increase in the number of endothelial keratoplasties rather than a decrease in the absolute number of transplants. 42,43 Furthermore, although CXL was introduced in Europe 20 years ago, KC remains the most common cause of corneal transplants in many regions. [44][45][46] Reports have found a reduction in the number of keratoplasties for KC, suggesting that improved contact lens technology is the main reason for this reduction.…”

Prevalence of Keratoconus in the Young Eastern Population of Saudi Arabia

“…In 2003, a novel treatment known as corneal collagen crosslinking was introduced, effectively strengthening the cornea and stabilizing the disease [ 8 ]. This treatment has globally reduced the need for corneal transplantation, as recent data indicates [ 9 - 10 ]. Early diagnosis, especially with the availability of cross-linking treatment, is critical to preventing further vision impairment.…”