HYDROGEN FLUORIDE CHEMICAL LASER SYSTEM FOR CORNEAL MICROSURGERY

IT IS PROPOSED TO DEVELOP A PULSED HYDROGEN FLUORIDE (HF) CHEMICAL LASER SYSTEM THAT IS SPECIFICALLY DESIGNED FOR USE IN CORNEAL MICROSURGERY. LASER PARAMETERS SUCH AS PULSE ENERGY, PULSE DURATION, BEAM QUALITY, AND OUTPUT SPECTRA WILL BE OPTIMIZED FOR APPLICATION IN CORNEAL MICROSURGERY. ISSUES RELATED TO USE IN A MEDICAL ENVIRONMENT, SUCH AS LASER SIZE AND PACKAGING, FUELS AND EXHAUST HANDLING, EMI SUPPRESSION, AND FIBEROPTIC DELIVERY OF LASER RADIATION, WILL BE ADDRESSED. THE SPECIFIC AIMS AND OBJECTIVES OF THE PROPOSED RESEARCH ARE: (1) TO DETERMINE OPTICAL PROPERTIES AND OPTIMAL ABLATION PARAMETERS FOR EFFICIENT MICROSURGICAL REMOVAL OF CORNEAL TISSUE; (2) TO DETERMINE SPATIAL AND TEMPORAL RESOLUTION AND CONTROL REQUIREMENTS FOR OPTIMAL TISSUE REMOVAL; (3) TO EVALUATE ADJACENT TISSUE DAMAGE BY HISTOLOGICAL EXAMINATION OF POSTIRRADIATED TISSUES; (4) TO DEVELOP A PROTOTYPE HF CHEMICAL LASER SYSTEM WITH REFINED LASER PARAMETERS FOR CORNEAL MICROSURGERY AND (5) TO CONSIDER CATHETER DELIVERY OF LASER RADIATION BY MEANS OF A FIBEROPTIC SYSTEM. THE METHODOLOGY OF PHASE I WORK WILL INCLUDE MODIFICATION OF A HELIOS MODEL PCLI-PULSED HF CHEMICAL LASER TO PROVIDE VARIATION OF LASER PARAMETERS, MICROSCALE LASER/TISSUE INTERACTION EXPERIMENTS, AND PRE-ANDPOSTIRRADIATION CHARACTERIZATION OF TISSUE SAMPLES. IF SUCCESSFUL, THE PROPOSED PROGRAM WILL BE CONTINUED IN PHASE II AND III WORK TO DEVELOP A NEW CLINICAL INSTRUMENT THAT PERMITS REFINED CORNEAL MICROSURGERY USING SAFE AND EFFECTIVE INFRARED LASER IRRADIATION.