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Retinopathy of prematurity (ROP) is a bilateral disorder of abnormal retinal vascularization in premature infants, especially those of lowest birth weight. Outcomes range from normal vision to blindness. Diagnosis is by ophthalmoscopy. Treatment of severe disease may include cryotherapy or photocoagulation; other treatment is directed at complications (eg, retinal detachment).
The inner retinal blood vessels start growing about midpregnancy, but the retina is not fully vascularized until term. ROP results if these vessels continue their growth in an abnormal pattern, forming a ridge of tissue between the vascularized central retina and the nonvascularized peripheral retina. In severe ROP, these new vessels invade the vitreous. Sometimes the entire vasculature of the eye becomes engorged (plus disease).
Susceptibility to ROP correlates with the proportion of retina that remains avascular at birth. More than 80% of neonates weighing < 1 kg at birth develop ROP. The percentage is higher when many medical complications exist. Excessive (especially prolonged) O2 therapy increases the risk. However, supplemental O2 is often needed to adequately oxygenate the infant even though a safe level and duration of O2 therapy have not been determined.
Diagnosis
Diagnosis is made by ophthalmoscopic examination, which shows a line of demarcation and a ridge in mild cases and proliferation of retinal vessels in more severe cases. Because significant ROP is rare in appropriately managed infants weighing > 1500 g at birth, alternative diagnoses should be considered in these infants (eg, familial exudative retinopathy, Norrie's disease).
Prognosis
Abnormal vessel growth often subsides spontaneously but, in about 4% of survivors weighing < 1 kg at birth, progresses to produce retinal detachments and vision loss within 2 to 12 mo postpartum. Children with healed ROP have a higher incidence of myopia, strabismus, and amblyopia. A few children with moderate, healed ROP are left with cicatricial scars (eg, dragged retina or retinal folds) and are at risk of retinal detachments later in life; rarely, glaucoma and cataracts can also occur.
Treatment
In severe ROP, cryotherapy or laser photocoagulation to ablate the peripheral avascular retina reduces the incidence of retinal fold and detachment. Therefore, all high-risk infants should be examined by an ophthalmologist before 6 wk of age. Retinal vascularization must be followed at 1- to 2-wk intervals until the vessels have matured sufficiently. If retinal detachments occur in infancy, scleral buckling surgery or vitrectomy with lensectomy may be considered, but these procedures are late rescue efforts with low benefit.
Patients with residual scarring should be followed at least annually for life. Treatment of amblyopia and refractive errors in the first year optimizes vision. Infants with total retinal detachments should be monitored for secondary glaucoma and poor eye growth and referred to intervention programs for the visually impaired.
Prevention
Prevention of premature birth is the best way to prevent ROP. After a preterm birth, O2 should be supplemented only as needed to avoid hypoxia documented by ABG or pulse oximetry. Vitamin E and restricted light are not effective.
Last full review/revision March 2007 by James W. Kendig, MD
Content last modified February 2012
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