The severity of ROP is divided into five
stages. Stage 1 can be seen as a line between
the developed and undeveloped areas of the retina. Stage 2 can be seen as a ridge between the
two areas. Stage 3 contains new, abnormal
blood vessels on and around the ridge. Stage 4
presents as leakage from the new blood vessels
and scarring resulting in some retinal detachment. Stage 5 is the detachment of the entire retina. The retina is divided into three zones, and
the Stage and Zone location of ROP determines
the level of disturbance to vision. Zone I is just
outside the optic nerve and includes the macula. If the line of ROP occurs here, vision can be
very poor, including no peripheral vision. Zone II
is the next area, outside the macula, including
most of the visual field, minus central and extreme peripheral vision. If ROP occurs here, vision can vary from limited central to loss of some
peripheral vision. Zone III includes the external,
mostly temporal area of the retina (Agarwal,
Azad, Chandra, Chawla, Deorari, & Paul, 2012)
and (Corn & Erin, 2010). Vision loss here will be
the least of all, generally some degree of periphery. The determination of and type of treatment
depend on the location and severity of
ROP (Corn & Erin, 2010).
Detection of ROP
44
Screening for ROP must be performed on a
tiny, preterm, fragile infant. Since there are no
symptoms, a dilated exam is necessary to detect
the disease. ROP doesn't usually develop earlier
than 2 weeks after birth. The median gestational
age of detection of stage 1 ROP is 34 weeks, and
vascularization of the retina is complete by 40
weeks. It is suggested that screening should be
done at 31 weeks GA, or 1 week of age (after
birth). The ophthalmologist administers numbing
and dilating drops, the eye is held open with a
