Contact fiberoptic laser transscleral Cyclophotocoagulation (TSCPC) is an aqueous inflow-reducing surgical treatment for glaucoma. One delivery device uses a 600-μm diameter quartz glass fiberoptic with a hemispheric tip. A larger fiberoptic diameter would reduce fluence through conjunctiva and sclera. This study determined the relation of fiberoptic to ciliary body burn diameters after TSCPC with the IRIS Medical SLx diode laser system in human autopsy eyes.Materials and Methods
Laser energy was applied with two models of delivery probe that were identical except for fiberoptic diameter (600 or 800 μm). Both had hemispheric tips, each with the hemisphere radius equal to the radius of the fiberoptic. Six fresh human autopsy eyes (three pairs) were used, each receiving eight diode laser applications at 1.75 (2 eyes) or 2.0 (4 eyes) watts for 2.5 seconds—four applications per eye with the 600-μm fiberoptic and four with the 800-μm fiberoptic. Eyes were fixed in 10% formalin then opened coronally at the equator. Inner surface burn diameters were measured parallel and perpendicular to the limbus using calipers and an operating microscope at 10° magnification.Results
Ciliary body burns with the 600− and 800-μm fiberoptic tips had nearly the same average diameter, range of diameter, average area, and range of areas.Conclusion
The 800-μm fiber, which has a 78% larger cross-sectional area than a 600-μm fiber, reduces fluence through ocular surface tissue during diode laser TSCPC, theoretically decreasing the risk of surface burns. In this study, the larger fiber gives essentially the same size ciliary body coagulation as obtained with the 600-μm fiberoptic. This suggests that the larger fiberoptic, compared with the standard 600-μm fiberoptic, will be more safe yet equally effective for TSCPC.