Background and objective: To determine the effectiveness of minimal intensity diode laser (810nm) photocoagulation (MIP) for diffuse diabetic macular edema (DDME).
Methods: Patients demonstrating diffuse diabetic macular edema (DDME) were treated with minimal intensity diode 810 laser photocoagulation or modified grid photocoagulation consecutively. Patients were seen and reevaluated at regular follow up visits every 3 to 4 months and retreated if residual diffuse diabetic macular edema was still present. Selected patients were tested with Goldmann visual field, pre and post-treatment. Visual improvement, visual loss, visual field, reduction/elimination of macular edema, and a number of treatments were studied.
Results: Reduction/elimination of DDME was observed in approximately 74% of eyes with 24 months follow up. The number of treatments per eye ranged from 1 to 5. The presence of cystoid macular edema, initial poor visual acuity, the presence of coexisting macular ischemia, or a history of systemic hypertension did not effect the outcome. Patients without a history of systemic vascular disease had a better chance of visual stabilization or improvement compared to those patients with a history of systemic vascular disease. Eighty-eight percent of patients had at least stable visual acuity at the last follow up visit. No post-treatment subjective complaints of increased pericentral scotomas were encountered in this group of patients and post-treatment atrophic scarring was substantially reduced, by using minimal intensity diode laser 810 photocoagulation, compared to eyes previously treated with shorter wavelengths and more visible burns.
Conclusion: Minimal intensity diode laser 810nm modified grid laser photocoagulation for diffuse diabetic macular edema (DDME) is effective in reducing/eliminating DDME, although resolution of edema may be slightly prolonged and may require 1 or 2 additional treatments compared to eyes previously treated with shorter wavelengths and more visible burns. However, this method appears to be advantageous in that it appears to reduce the objective and subjective effect on the pericentral visual field, as well as substantially reducing the post-treatment atrophic scarring seen in patients treated with shorter wavelength lasers and move visible burns.