The comments of Vinekar and associates are valuable and support much of our approach in the management of retinopathy of prematurity (ROP). We are aware of numerous publications (reviewed recently) that have recognized ROP not as an isolated ocular disease but as a manifestation of systemic problems, to which the developing retina gets exposed in the postnatal and antenatal period. We specifically emphasized only anemia in our paper due to varying and evolving protocols among neonatologists for management of anemia. However, all other systemic factors where there has not been much difficulty in defining protocols with the neonatologists (including thrombocytopenia, sepsis, and chronic lung disease) are actively pursued by us and corrected from the time of first screening. This results in not only reduced incidence and less severe disease, but also rapid and favorable outcomes both in the spontaneous resolution group and in the laser group. Since there is no control group where the systemic factors were not attended to, the data could not be analyzed for a subset that received or did not receive treatment for systemic factors including correction of low platelet levels.
Details of our laser techniques have been published and are also mentioned in the discussion and methodology sections of our paper. Briefly, we recommend to treat aggressive posterior ROP (APROP) very early, as soon as it manifests from an immature retina to appearance of the first sign of APROP, before too many flat new vessels appear (ie, when the vessels just begin to appear). This is ensured by early screenings from day 20 in the smallest babies and not later than day 30 in all babies. Secondly, treatment should be confluent, including all the “posterior pockets” of avascular retina up to the site where the original vasculogenesis had stopped. The more advanced the disease is at presentation, the more important and difficult it is to seek out these sites because they get overwhelmed by the advancing edge of the new vessels. Lastly, alternate-day, meticulous evaluation helps to do complete ablation of all these “missed” and “exposed” posterior areas.
Only Zone I APROP cases were included, as mentioned in our methodology. The characteristics of the “closed-loop” shunt vessels, flat new vessels, posterior extent of vasculogenesis, “gliosis” and vitreous condensation around the shunts, ridge elevation, and the extent of “plus” in retinal and iris vessels are more critical to assess severity and response to therapy of APROP than its location in arbitrarily demarcated Zone I or posterior Zone II. We emphasize that current definition and classification is quite inadequate and does not recognize the different manifestations of disease severity of APROP.
We agree that disease presentation is undergoing a change in trend as care of the newborns is moving from larger cities to smaller towns and rural areas of India. An increase in ROP and APROP cases, seen in the trend graph shown in Figure 1, reflects some of these changes. Our report included babies from neonatal centers in tertiary hospitals, semi-urban areas, and also some basic centers located in rural areas, largely due to our extensive referral and screening base. The influence of type of neonatal care on ROP cases in our database is currently under analysis.