Microwave diathermy of the retina and choroid.
Microwaves were used to induce chorioretinal scar formation in normal rabbit eyes. We have developed a directional 6.8-gigahertz microwave applicator with a rectangular aperture. It was designed to mimic the shape and function of a T-shaped scleral depressor. For treatment, the applicator was placed on the conjunctiva over the sclera. Then, indentation was used to visualize probe placement during indirect ophthalmoscopy. Thermocouple-controlled heating was initiated such that conjunctival temperatures in a range of 51 degrees C to 65 degrees C were induced for 10 seconds per treatment. We found that treatment at temperatures of 51 degrees C or 52 degrees C for 10 seconds produced circular areas of acute retinal whitening. From these microwave-induced lesions, there evolved chorioretinal attenuation with and without evidence of retinal pigment epithelial hyperplasia. No evidence of scleral damage was noted at these thermal doses.
Finger
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Department of Ophthalmology, North Shore University Hospital-Cornell University Medical College, Manhasset, NY 11030.
Svitra
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McCormick
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Presser
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D000818:Animals; D001706:Biopsy; D002829:Choroid / Q000601:surgery*; D002921:Cicatrix / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D003972:Diathermy / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D004195:Disease Models, Animal; D005069:Evaluation Studies as Topic; D005451:Fluorescein Angiography; D009887:Ophthalmoscopy; D011817:Rabbits; D011829:Radiation Dosage; D012160:Retina / Q000601:surgery*; D013696:Temperature; D013817:Thermography; D013997:Time Factors