Participants and examination
This study consists of the medical records of 131 VLBW infants admitted
in NICU. The World Health Organization (WHO) defines VLBW, a subgroup of
low birth weight, as the birth weight between 1000 g and 1500
g.(12) Babies were born with a BW of ≤1500 g and/or a
GA of ≤30 weeks and those with available ROP examination records and
data of weights at the sixth weeks of life were included in the study.
Infants with unstable clinical course preventing ROP examination were
excluded from the study. The initial screening for ROP was performed in
the fourth weeks of postnatal life. Time intervals between examinations
were repeated weekly or bi-weekly based on the guidelines described by
the American Academy of Pediatrics, the American Academy of
Ophthalmology, and the American Association for Pediatric Ophthalmology
and Strabismus.(13) After pupillary dilation with
2.5% phenylephrine and 0.5% tropicamide eye drops, eye examinations
assisted with binocular indirect ophthalmoscopy, 28-diopter lens and
scleral indentation with an eye speculum were performed by the same
ophthalmologist (SG).
The retinal findings indicating the stage of disease, location by zone
and presence of plus disease were classified regarding to the current
International Classification of ROP.(14) In accordance
with the international classification, patients were divided into three
different groups as follows; the absence of any stage of ROP (no-ROP),
the presence of any stage of ROP without needing any treatment (Type-2
ROP) and severe ROP that indicates the need for an urgent intervention
via laser photocoagulation or intravitreal injections (Type-1 ROP).