• Monkey retinas were studied histopathologically to assess the relative effects of immediate versus delayed repetitive photocoagulation with the argon laser. Immediate retreatment adds relatively little damage to that created in the retinal nerve fiber layer by the initial photocoagulation. Delayed retreatment increases destruction of all retinal layers, including the nerve fiber layer, and also increases the chance of inducing hemorrhage. When argon laser retreatment of a retinal locus is necessary, it is much safer to do so immediately (within a few hours) rather than after days or weeks.
Apple DJ, Wyhinny GJ, Goldberg MF, Bizzell JW, Broderson JP. Experimental Argon Laser PhotocoagulationIII. Relative Dangers of Immediate vs Delayed Retreatment. Arch Ophthalmol. 1976;94(2):309-312. doi:10.1001/archopht.1976.03910030157015