Retinopathy of prematurity

Question 1 (10 marks)

a) Define the screening criteria for retinopathy of prematurity and state when the first examination should occur. (4 marks) Screening is offered to infants with a gestational age of 30 weeks or less or a birth weight of 1500 g or less, with some guidelines adding selected unstable infants with a higher gestational age or birth weight ^[2]. The first retinal examination should be performed at 31 weeks postmenstrual age or 4 weeks of chronological age, whichever is later ^[2].

b) Describe the three axes used to classify ROP and define plus disease. (3 marks) ROP is classified by zone, stage, and the presence of plus disease ^[4]. The zones are concentric circles centred on the optic disc: Zone I is posterior with a radius twice the disc-to-fovea distance, Zone II extends to the nasal ora, and Zone III is the temporal crescent ^[4]. Plus disease is venous dilation and arteriolar tortuosity of the posterior retinal vessels greater than or equal to the standard published photograph ^[4].

c) This infant's findings (Zone II stage 3 with plus) meet Type 1 criteria. Outline the management. (3 marks) This infant has Type 1 ROP, which requires treatment within 72 hours ^[1]. The options are laser photocoagulation of the avascular retina or intravitreal anti-VEGF therapy, chosen on the basis of zone, the infant's systemic state, and the reliability of follow-up ^[1]. After treatment the infant needs close surveillance for recurrence or reactivation, particularly if anti-VEGF is used ^[3].