Paediatrics: Retinopathy of prematurity
Retinopathy of prematurity (ROP) is a leading cause of preventable blindness. Infants born <32/40 and those weighing <1500g at birth are at the greatest risk.
Retinopathy of prematurity
Retinopathy of prematurity (ROP) is a leading cause of preventable blindness. Infants born <32/40 and those weighing <1500g at birth are at the greatest risk. The incidence is decreasing and recent data suggest that around 90% of infants born weighing >1000g will have no ROP, however, this number drops to only 38% for those <750g at birth. The cause is multifactorial. In utero, the retinal vasculature develops in a relatively hypoxic environment, with vessels stimulated to grow towards the most hypoxic regions. This development is disrupted with preterm delivery. ROP is associated with retinal arterial hyperoxic vasoconstriction and retinal ischemia during retinal development before 32wks gestation. It is, therefore, essential to monitor and prevent hyperoxia in infants requiring supplemental O2. Minimizing variability in oxygenation may also be important.
ROP is proliferative retinopathy that is classified according to internationally accepted guidelines.
- 27/40: first screen at 30–31/40 CGA.
- 27–32/40: first screen at day 28–35 of life.
- Screen 2wkly thereafter unless:
any stage 3 disease;
any plus/pre-plus disease;
vessels end in zone 1, or posterior zone 2;
a weekly screening if present.
- Screening is performed by indirect ophthalmoscopy after pharmacological pupil dilatation or increasingly by wide-field digital retinal imaging.
- Screening continues until vascularization has progressed into zone 3 (usually >36/40).
Diode laser treatment within 72hr (48hr if aggressive disease) of meeting any of the treatment criteria.
Babies should be ventilated, adequately sedated, and given a muscle relaxant. Atropine should be available.
Side effects of treatment include:
- Need for re-ventilation.
- Ocular hemorrhage.
- Eyelid trauma.
- Laser burns.
Infants should be re-examined 5–7 days following treatment, and if no regression, re-treatment should be performed at 10–14 days after initial therapy. Steroid eye drops may be useful in decreasing post-operative swelling. Direct injections of monoclonal antibodies against vascular endothelial growth factor (VEGF) are showing promise as an alternative.
Almost all cases can be treated effectively so blindness is a rare outcome. There may be reduced visual fields in severe cases. Refractive errors are common.