Retinopathy of Prematurity

Retinopathy of prematurity is a neonatal complication, primarily related to exposure to elevated oxygen tension during the period in which the retina is maturing. Embryologically, the retina begins vascularization at 16 weeks gestational age, and is complete on the nasal side by 8 months, and entirely complete at term. The oxygen causes constriction of the capillaries growing in the forming retina, and results in obliteration of the capillary bed. This is followed by neovascularization of the vitreous and retinal edema. Fibrosis then occurs and is followed by traction and detachment of the retina.

Classification: ROP is classified by stage, the number of circumferential clock hours of involved retina, and by zone. Zone I is defined as 30 degrees around the macula, zone II extends to the ora serrata nasally, and to the anatomic equator temporally, and Zone III is the small crescent of remaining temporal territory.

Stage I: A demarcation line between the vascularized and still avascular retina.

Stage II: The line develops into a raised ridge, projecting into the vitreous. Histologically, there is evidence of an AV shunt in this tissue.

Stage III: Extraretinal fibrovascular proliferation extending from the ridge; vascular tufts may be present posterior to the advancing ridge.

Stage IV: Fibrosis, scarring, traction, retinal detachment (subdivided into those with or without macular involvement).

Stage V: Retinal detachment.

Plus Disease: Vessels posterior to the ridge become dilatated and tortuous, engorgement of the iris, hazy vitreous.

Diagnosis: Initial exam at 4-7 weeks of life (or at discharge, if earlier) for oxygen exposed infants less than 1800g or less than 35 weeks GA, or for any infant less than 1300 grams or 30 weeks. If negative, follow-up exams in 2-4 weeks. If ROP, more frequent follow-up may be indicated.

Treatment: Laser photocoagulation is the treatment of choice for stage III+. Cryopexy is an older technique which is less popular now. Vitamin E administration may help , possibly by functioning as a free radical scavenger. After treatment, patients will need regular eye exams.

Neonatology

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Last modification: July 8, 1997