Update on corneal collagen crosslinking for ectasia

Abstract

Purpose of reviewCorneal collagen crosslinking (CXL) is a minimally invasive treatment that can stabilize corneal ectatic disorders including keratoconus, pellucid marginal degeneration, or postrefractive surgery ectasia. The benefits of CXL have been well documented. New research is focused on modifying current treatment protocols with the goals of maximizing corneal stability while also shortening overall procedure time. Recent findingsAccelerated CXL protocols have the goal of delivering the same ultraviolet A intensity as conventional protocols, but over a shorter time period. Accelerated protocols have shown success to date, but there are concerns for long-term corneal stability. Pulsed protocols may increase the long-term efficacy of the accelerated designs. In addition, transepithelial crosslinking protocols have been designed with the goal of reducing postoperative pain and lower the risk of infectious complications of epithelial-off conventional protocols. SummaryNewer CXL protocols attempt to make the procedure safer and more effective. Current research is promising, but long-term studies are essential to understand how the new protocols may affect corneal stability.

Prospective Safety Evaluation of the Femtosecond Laser-Assisted Keratomileusis Procedure in Correcting Residual Ametropia in Patients After Deep Anterior Lamellar Keratoplasty

“…It is certain that a refractive procedure is safer for patients who have undergone a cornea transplant than another transplant, which carries a much greater burden and poses a higher risk for the patient, especially as refractive procedures do not require corneal tissue [ 21 , 22 ]. In refractive surgery, the most important evaluated parameters are uncorrected vision acuity (UCVA), which is visual acuity expressed in D without any correction, and best-corrected vision acuity (BCVA), which is visual acuity expressed in D after the application of an appropriate vision correction, determined during the eye examination [ 23 – 25 ]. After the laser vision correction procedure, the UCVA value corresponds to the visual acuity the patient would have achieved after correction before the procedure [ 23 – 25 ].…”

“…In refractive surgery, the most important evaluated parameters are uncorrected vision acuity (UCVA), which is visual acuity expressed in D without any correction, and best-corrected vision acuity (BCVA), which is visual acuity expressed in D after the application of an appropriate vision correction, determined during the eye examination [ 23 – 25 ]. After the laser vision correction procedure, the UCVA value corresponds to the visual acuity the patient would have achieved after correction before the procedure [ 23 – 25 ]. This explains why the UCVA values before and after a successful procedure are significantly different from each other, while the corresponding BCVA values are not statistically significant [ 23 – 25 ].…”

“…After the laser vision correction procedure, the UCVA value corresponds to the visual acuity the patient would have achieved after correction before the procedure [ 23 – 25 ]. This explains why the UCVA values before and after a successful procedure are significantly different from each other, while the corresponding BCVA values are not statistically significant [ 23 – 25 ]. On the other hand, the small differences between the UCVA and BCVA values after the procedure are attributable to the fact that laser vision correction does not fully correct visual impairment [ 23 – 25 ].…”

The effect of accelerated pulsed high-fluence corneal cross-linking on corneal endothelium; a prospective specular microscopy study

“…Recent systematic literature reviews [ 1 , 27 , 28 ] found that the clinical outcomes and safety of conventional and accelerated CXL protocols were comparable. In addition, pulsed mode may increase the long-term efficacy and safety of the accelerated protocols.…”

Efficacy and Safety of Standard Corneal Cross-Linking Procedures Performed With Short Versus Standard Riboflavin Induction: A Save Sight Keratoconus Registry Study

“…[13][14][15][16] To reduce treatment times, variations in CXL protocols have arisen. [13][14][15][16][17] Different riboflavin induction times have been used across the globe. To the best of our knowledge, there are no published studies on the comparative effectiveness of different riboflavin induction times during CXL.…”