Laser soldering of the cornea in a rabbit model using a controlled-temperature CO₂ laser system

Purpose. To determine the feasibility and reproducibility of laser welding of cornea with a CO₂ laser system capable of real times infrared fiberoptic radiometric control of tissue temperature. Methods; A fiberoptic radiometric temperature control system for the CO₂ 10.6μm laser was developed that enabled a real time nontactile temperature measurement of welding surface. The system was tested on the cornea in 40 in vitro bovine eyes, and also in 6 in vivo corneas of rabbit eyes. Welds performed at a set point temperature of 65c°, with or without adjuvant 50% albumin solder. Leaking pressure, surgical time and histologic evaluation were determined for welding and for suturing controls of 6 mm central corneal perforating cuts. Results. Effective watertight corneal welds were achieved. The mean (±SD) leaking pressure of welded bovine corneas with adjuvant albumin solder was 109 ± 30 compared to 51± 7mm Hg in suture controls (N=20; P<0.001). Mean welding time of in vivo rabbit corneas was 140± 17 and 330 ± 30 seconds for corneal suturing (N=12; P<0.001). Histologic examination of rabbit corneas one day after welding revealed sealed corneal edges with a small gap bridged over by coagulated albumin solder. Stromal lamellae were organized with minimal inflammatory reaction, in contrast to marked inflammatory response in suture controls. There was no thermal damage seen in stroma along wound edges. Conclusions. The technology described appears to be a rapid reliable and versatile closure technology that can overcome many of the technical difficulties and disadvantages of conventional corneal suture technique.