Sir,

We thank Drs Uparkar and Kaul for their correspondence1 with regard to our paper on laser photocoagulation, posterior to the neovascular ridge in infants with severe subgroup of Type I retinopathy of prematurity.2

In addressing the suggestion that confluent secondary laser treatment be applied anterior to the ridge, we wish to confirm that all of these infants did receive laser to the avascular anterior retina and to all skip areas in addition to laser posterior to the ridge.

We agree with Drs Uparkar and Kaul that posterior laser should be considered with great caution; however, all of our infant eyes represented a very severe form of Type I ROP and were treated under general anesthesia where there was maximum control of laser application within the temporal arcades. Minimal temporal arcade traction was permitted in our treated eyes, as we commonly observe this feature in eyes with severe Type I ROP prior to treatment; however, a minimum distance of 3000 μm (two disc diameters) between the fovea and temporal ridge was required in order to minimize potential complications of posterior laser.

Two eyes in this 3-year series progressed to 4A retinal detachment and required further intervention, however 89% of eyes did not go on to stage 4 retinal detachment and experienced regression within 1 week, which we consider to be a rapid regression of very severe disease after laser treatment. Lepore and colleagues3 report fluorescein angiography cases with avascular loops, which exist posterior to the ridge, and hypothesize that these ischemic posterior retina areas may contribute significantly to the production of VEGF. We also hypothesize that additional laser to these posterior ischemic retina areas may facilitate regression of neovascularization in this subgroup of infants with very severe zone II, stage 3 ROP.

We describe clear morphological criteria for consideration of posterior laser in a group of premature infant eyes with very severe Type I ROP, which may halt progression of the disease and minimize visual loss from cicatricial macular changes or avoid advancement to stage 4 or 5 ROP warranting vitreoretinal surgery.