Abstract
Purpose:
To evaluate the effect of laser welding on wound strength in penetrating keratoplasty and characterize the microscopic changes induced by laser corneal welding
Methods:
Five eye bank corneoscleral rims were cut using the Intralase femtosecond laser in a modified zigzag configuration. Following the placement of 8 interrupted 10-0 nylon sutures, a saturated indocyanine green (ICG) solution was applied to the wound interface. The ICG-stained wound edges were irradiated using a 25 gauge endoprobe connected to a 810 nm diode laser emitting at low power (70 mW), held 1-2 mm away from the wound edge. Wound burst pressure was evaluated before and after laser welding. Laser welded corneas were then sectioned and examined under high magnification light microscopy and second harmonic generation (SHG) microscopy to evaluate stromal collagen organization within the wound margin.
Results:
There was no statistically significant difference in wound burst pressure before (24.9 +/- 13.9 mmHg) and after laser welding (28.9 +/- 9.1 mmHg, p=0.76). Fragility of the wound interface was also observed during tissue sectioning. High magnification microscopy and SHG imaging of laser welded corneas showed ICG uptake at the wound edges, irregular stromal melt at the wound interface, and tissue disruption with prominent wound gape and no detectible collagen renaturation.
Conclusions:
While diode laser welding does result in stromal melt and uptake of ICG in cadaver corneas pre-cut with the femtosecond Zig-Zag incision, it does not add significant mechanical stability to the wound.