Failure of pan-retinal laser photocoagulation to regress neovascularization in proliferative diabetic retinopathy

Objectives: (i) To illustrate the occurrence of failure of regression of neovascularization (NV) following adequate initial and supplemental pan-retinal laser photo- coagulation (PRP) using 3 case histories (ii) To review the literature on possible aetiogenesis and further management options Methods: The hospital records of 3 patients with proliferative diabetic retinopathy (PDR) and in whom NV did not regress following multiple sessions of PRP were reviewed. The data extracted included status of diabetic control, status of proliferative diabetic retino-pathy, and details of laser treatment and outcome. Results: The 3 patients were all middle-aged males in stable clinical condition and with non-insulin dependent diabetes of more than 12 years duration. Two of the patients were managed in Saudi Arabia where the argon green laser was used, while the third one was managed in Nigeria with the diode laser. The number of laser burns for the two patients who were undergoing laser treatment for the first time were not less than 1,750, while the amount during supplemental laser sessions for each of the 3 patients varied according to the available retinal space that had not been treated during past laser treatment sessions. The power settings were generally made to produce moderate laser burns with the spot size set at 500 micro-meters and a duration of 0.1 seconds. Conclusions: Despite adequate initial and supplemental PRP in these 3 patients, their NV failed to regress. It is recommended that a more extensive PRP be made during initial sessions and liberal use of supplemental PRP be made in cases of non-regression. Nigerian Journal of Ophthalmology Vol. 13(2) 2005: 54-5