Abstract
Purpose:
Corneal crosslinking procedures are offered as a treatment for keratoconus and corneal ectasic disorders. This study was undertaken to investigate the comparative stromal changes after the UVA-crosslinking on a riboflavin-debrided and a riboflavin-transepithelial treated porcine cornea using multiphoton microscopy and second harmonic generation signals.
Methods:
Fifteen fresh pig eyes were treated using either the standard method of riboflavin-UVA crosslinking or the transepithelial method (riboflavin TRIS-EDTA) for 30 min at irradiance of 3mW/cm2. All corneas were then stained with a cell death marker and processed for non-invasive multiphoton microscopy and second harmonic signal imaging. Data collected were analyzed using image J.
Results:
Standard CXL treatment resulted in severe loss of the classic interwoven collagen architecture all the way up to 300 uM depths, whereas, similar changes were noted only up to 150 uM depth in the TE method of CXL. Significantly higher numbers of dead keratocytes were counted at all the depths in the standard CXL exposed eyes in contrast to fewer keratocyte deaths that were more pronounced only in the anterior stroma in the TE-CXL treated corneas (p<0.05). However, in both the treatment groups decreasing number of dead keratocytes were noted in deeper stroma than in the anterior stroma, suggesting the role of riboflavin for crosslinking.
Conclusions:
This is the first study that shows direct comparison between the standard and the transepithelial (RicrolinTE, Sooft Italia) method of riboflavin UVA-crosslinking. We have shown structural alterations between the cross-linked corneal stroma in the two currently used method of treatment. This information will be useful in clinical decision making when choosing the treatment strategy on diseased thin corneas.
Keywords: 484 cornea: stroma and keratocytes •
574 keratoconus