A prematurely born baby at a gestational age of 30 weeks and birth weight of 1120 grams was referred to our clinic at postmenstrual age of 37 weeks for the treatment of stage 4A ROP in her right eye. It was a zone 1 disease, and even the macula was not yet vascularized in either eye. There was a tractional retinal detachment at the nasal side of the right optic disc.
A lens-sparing vitrectomy was done with laser ablation of zone 2. Zone 1 (macula) was not lasered, and an anti-VEGF injection was given at the end of the surgery. The retina was completely attached at both 2-weeks and 6-months postoperatively. The retina was finally completely vascularized in zone 1 six months postoperatively.
Learning Points:
The current ROP classification system is based on the International Classification of Retinopathy of Prematurity, Third Edition (ICROP 3; Ophthalmology 2021;128:e51-e68), and there is no zone half in the zone descriptions. However, especially in developing countries with limited resources in neonatal intensive care units, ROP with avascular macula (even less than zone I, which could be called zone half!), as in the present case, can be seen. Such cases are usually called Aggressive ROP, which can progress to stage 4-5 very quickly.
It is generally recommended to laser the avascular retina during vitrectomy to control active disease. However, in zone 1 cases where the macular vascularization is not yet completed, as in our patient, we leave the zone 1 non-lasered to give a chance for macular vascularization after surgery. An anti-VEGF injection at the end of the surgery was therefore given to control possible disease activation due to the lack of laser treatment to the posterior nonperfused retina. To the best of our knowledge, this is the first presentation of such a treatment approach in the literature.
