Retinopathy of prematurity- an overview

Retinopathy of prematurity is a developmental abnormality of retina occuring in premature infants. Other predisposing factors include low birth weight, hyperoxia, hyperglycaemia, anemia, apnea, mechanical ventilation, blood transfusion, intraventicular haemorrhage & sepsis. Predisposing gene mutations are also reported. Retinal area is divided into 3 zones & there are 5 stages of ROP. Plus disease is characterised by significant vasodilation & tortuosity of posterior retinal arterioles. Threshold ROP & severe forms of prethreshold ROP require immediate treatment & are included in type I ROP category. As ROP is asymptomatic in neonatal period, screening is mandatory. Screening  is recommended for infants with birth weight between 1500-2000 g or gestational age >30 weeks with risk factors. For babies with no ROP during first exam, follow up is done until retinal vessels have developed & for babies with ROP follow-up is based on location & severity. About 90% babies with Stage 1 & 2 ROP improve spontaneously without treatment. However about 50% babies with Stage 3 & majority with Stage 4 may develop serious eye damage. Types of treatment include cryotherapy, laser therapy & retinal surgeries. Anti-VEGF has been used in severe ROP. Surgical procedures include scleral buckling & vitrectomy. Babies with ROP may develop squint, strabismus, amblyopia, myopia, glaucoma, cataract, nystagmus & corneal opacity. Early intervention & sensory stimulation improves outcome. Strategies to control ROP include prevention of preterm births, improved neonatal care, early detection of infants requiring treatment & reducing oxygen toxicity by targeting lower saturations . Early intervention improves visual outcome.