Publication Exclusive: Combination of ROP treatments may help eliminate ‘destructive’ laser therapy

Retinopathy of prematurity is a disease in premature infants who today, secondary to advanced neonatal intensive care units, are surviving at ever lower birth weights and weeks of gestation. These infants almost universally require oxygen supplementation, and both excess oxygen and hypoxia can contribute to the disease.

At about 16 weeks, the retina begins to develop vascularization, and this process is mediated by many cytokines and growth factors, including VEGF. The vessels grow outward from the optic nerve toward the retinal periphery, and this process is not fully completed in the temporal periphery until after full-term birth. The normal growth of blood vessels is directed toward relatively low oxygen areas of the retina. If excess oxygen is given, these normal blood vessels can fail to develop or regress. When the excess oxygen is removed, the blood vessels grow rapidly and are associated with fibrous tissue proliferation, which can also extend outside the retinal plane into the vitreous. Vitreous hemorrhage, retinal detachment, cataract, myopia, secondary glaucoma, strabismus and amblyopia are frequently associated with ROP.

All infants with a gestational age of less than 31 weeks or a birth weight of less than 1,250 g (2.76 lb) require screening for ROP. The examination requires indirect ophthalmoscopy with scleral depression, and significant skill is required to detect subtle changes. In some centers, retinal photography with a RetCam (Clarity Medical Systems) is utilized and reviewed by an ophthalmologist expert in diagnosis and staging.

The International Classification of Retinopathy of Prematurity (ICROP) uses a number of parameters to stage the disease. The retina is divided into zones. Zone 1 extends from the optic disc in a radius two times the distance to the macula. Zone 2 is the distance to the nasal ora serrata extended in a circle temporally. Zone 3 is the residual temporal crescent. These zones are utilized to localize the disease, and then it is staged. Stage 1 is a faint demarcation line, stage 2 has an elevated ridge, stage 3 includes extraretinal fibrovascular tissue, stage 4 has a sub-total retinal detachment, and stage 5 has a total retinal detachment. Plus disease describes complicating factors such as significant vessel dilation or tortuosity, vitreous or anterior chamber haze, iris vascular engorgement, or a persistent tunica vasculosa.

Click here to read the full publication exclusive, Lindstrom's Perspective, published in Ocular Surgery News U.S. Edition, December 10, 2015.