Abstract
Purpose: :
To investigate comparative cornea stiffness values in porcine corneas after standard crosslinking and a new, rapid method of crosslinking (flash-linking) using surface wave elastometry (Sonic Eye, PriaVision Inc, Menlo Park, CA).
Methods: :
Six porcine eyes were treated using a UVA double diode with 4.2 mW/cm2 UVA at 370 nm while applying 0.1% riboflavin-5-phosphate drops every 5 minutes as a photosensitizer for 30 min. The next 6 porcine eyes were treated with a single application of a customized photoactive crosslinking agent (PriaVision Inc) and 30 seconds of UVA light at the same power and wavelength. Before and following both experimental treatments, the Sonic Eye system was used to measure ultrasound surface wave propagation time between two fixed-distance transducers along central horizontal and vertical positions. Intraocular pressure was continuously monitored using a digital pressure monitor display (Infinity SC9000XL, Drager medical, Lubeck, Germany) after vitreous chamber cannulation with a 23-gauge needle.
Results: :
Mean surface wave velocity was 93.63±2.58m/s in group 1 vs. 82.78±2.58m/s in group 2 before treatment and 111.35±2.16m/s (group 1) vs. 108.48±2.42m/s (group 2) after crosslinking. The mean surface wave velocity increased by 17.7 units from 93.6 to 111.3m/s (p = 0.032) after crosslinking with UVA+riboflavin, and by 25.62m/s from 82.78 to 108.48m/s (p = 0.002) after "flash-linking" with the customized photoactive crosslinking agent. No statistically significant differences in surface wave velocity was noted after crosslinking between group 1 and group 2 (p=0.75).
Conclusions: :
A new, rapid method of crosslinking (flash-linking) is introduced by the use of a customized photoactive crosslinking agent. The method demonstrates similar efficacy in stiffening the cornea (when measured with surface wave elastometry) in comparison to standard crosslinking, but requires only 30 seconds of UVA exposure. This relatively short exposure saves significant time in the crosslinking of ocular collagen, and offers expanded flexibility of implementation to existing and potentially new clinical applications.
Keywords: cornea: clinical science • cornea: stroma and keratocytes • refractive surgery: other technologies