Evaluation of a KTP (potassium-titanyl-phosphate) 532 nm laser for endovaporization of choroidal melanomas

BACKGROUND AND OBJECTIVES: The purpose of this in vitro study is to evaluate the use of the KTP (potassium-titanyl-phosphate) 532 nm laser for future use in endovaporization of large choroidal melanomas. STUDY DESIGN/MATERIALS AND METHODS: A KTP 532 nm green laser coupled to a 0.3 mm fiberoptic probe was used to perform in vitro studies on human cadaver eyes and on one enucleated melanoma eye. The specimens were examined by histological staining (Masson-Trichrome) and scanning electron microscopy (SEM). RESULTS: Histological analysis of sclera, choroid, retina, and melanoma revealed different zones of collateral thermal tissue damage. These zones were analyzed quantitatively. We determined the best suitable laser parameters and the time for sclera penetration. CONCLUSIONS: The KTP-laser showed good potential in intraocular vaporization of choroidal melanomas. However, great differences in laser absorption between sclera and melanoma can cause significant complications such as perforation.