Estimation of the maximum number of argon laser burns possible in panretinal photocoagulation.

I measured the area of the retina in ten autopsy eyes and the area of 500 mu argon laser burns placed with both Goldmann and Rodenstock contact lenses in two eyes that were subsequently enucleated. The mean area of the retina available for panretinal photocoagulation is 1,050 mm2. The mean diameter of 500 mu argon laser burns is 490 mu when placed with a Goldmann contact lens and 810 mu when placed with a Rodenstock contact lens. The maximum number of 500 mu burns that can be used to treat the entire extramacular retina in the normal sized eye is approximately 5,500 when a Goldmann contact lens is used, and approximately 2,050 when a Rodenstock contact lens is used.