Authors' reply.

Thank you for the interesting comments on our article on “Analysis of prenatal and postnatal risk factors of retinopathy of prematurity in tertiary care hospital in South India”.[12]

In this regard, we wish to clarify the following points:

Our inclusion criteria consisted of the following:

Those infants with birth weight <1500 g, irrespective of gestational age, and all infants born at <32 weeks of gestation, irrespective of their birth weight

Those infants with a gestational age >32 weeks, with a birth weight between 1500-2000 g were screened at the discretion of the attending neonatologist, as these infants had some factors that increased their risk of retinopathy of prematurity (ROP), such as, exposure to oxygen for >30 days, respiratory distress syndrome, sepsis, multiple blood transfusions, multiple births, intraventricular hemorrhage etc.

This criteria was based on the screening guidelines mentioned in the study by Jalali et al.[3]

We have aimed to analyze the prenatal and postnatal risk factors for the development of severe ROP requiring treatment with a special reference to postnatal weight gain and hence have not explained the laser treatment in detail.

In our series, none of the infants had zone I disease or stage IV or V disease. Nine infants had stage III in zone II (qualifying to be threshold ROP) which were treated promptly. Of the 20 infants who had stage II zone II disease, 17 had type I disease. These infants were followed up more frequently and 7 eventually required treatment, because they progressed. The other 10 regressed. We also treated three infants for persisting new vessels at the edge of zone II and III, beyond 45 weeks.

The diagnostic consistency in plus disease is imperfect[4] and early intervention for zone II stage II plus disease (Type I ROP) is still controversial.[5] It is estimated that if treatment protocol is strictly adhered to in this sub-group, 44% of babies would be treated unnecessarily. It is estimated that 10 eyes must be treated to avoid 1 unfavorable outcome for zone II stage II plus disease.[6] Earlier treatment also means that treating less mature and consequently more unstable babies.[5] In our series, despite having full-fledged neonatal intensive care unit (NICU) backup, four babies out of 19 who underwent treatment, developed respiratory problems which required intervention. It is recommended that the clinical judgment is warranted in treating these babies as more research is needed to prove conclusively about the benefit of early treatment in zone II stage II plus disease. With this in mind, we followed these babies more frequently than treating them immediately. We feel that our stand is justified as 10 (59%) of these babies regressed spontaneously.