Anti-VEGF therapy for retinopathy of prematurity (ROP) has shown mostly successful results, but in cases that fail (i.e., an eye needing more than one treatment session), studies haven’t described how they were managed or the descriptions of characteristics. For this study, researchers investigated the anatomic features of treatment failure and long-term follow-up.

Of the 23 eyes managed for failure, three did so after 50 weeks post-menstrual age (PMA), a measure that combines the child’s gestational and post-birth age. Failure manifested as recurrent plus in 14 eyes, recurrent stage 3 in 13 eyes and retinal detachment in five eyes.

Most patients who failed a single dose of anti-VEGF had favorable outcomes after being retreated with either laser, repeat anti-VEGF, vitrectomy or a combination of modalities.

“Our finding of three of 23 failures occurring after 50 weeks PMA reinforces the concept that eyes previously treated with anti-VEGF, who have persistent peripheral avascular retina, continue to be at risk for recurrence,” the authors explained in their study. “For this reason, laser ablation of any peripheral avascular retina after 50 to 60 weeks PMA maybe advised.”

The authors suggest this because they believe that normal appearing retinal vessels can continue to grow into avascular retina until at least 50 weeks PMA, and one reason to consider treating for vascular arrest sooner would be “for fear of a patient becoming lost to follow-up and having continued risk for recurrent ROP that could go undetected.”

This happened with one of the patients. “In this case, recurrent stage 3 and plus disease were noted at 43 weeks,” the authors noted in their study. “We treated this recurrence with repeat bevacizumab and partial laser of avascular retina hoping for continued vascularization in the untreated retina temporal to the macula. However, vascularization did not progress after laser and repeat bevacizumab.”

Instead, they said, at 64 weeks, recurrent stage 3 prompted fill-in laser in both eyes, with the right eye then stabilizing, but the left eye developed stage 4a tractional retinal detachment (TRD).

“Our findings confirm that TRD in patients with ROP treated with anti-VEGF can be different than TRD seen after laser,” the authors concluded in their study. “The fibrosis and traction that cause TRD in eyes previously treated with anti-VEGF is not necessarily located at the junction of vascular-avascular retina. Instead, the fibrosis is often found in the location of the original ridge that was present at the time of the anti-VEGF injection. This fibrosis is posterior to the new location of the vascular-avascular junction because of the progression of retinal vascularization that occurs after injection of anti-VEGF.”