Retinopathy of Prematurity - Diagnosis

Diagnosis

Following pupillary dilation using eye drops, the retina is examined using a special lighted instrument (an indirect ophthalmoscope). The peripheral portions of the retina are sometimes pushed into view using scleral depression. Examination of the retina of a premature infant is performed to determine how far the retinal blood vessels have grown (the zone), and whether or not the vessels are growing flat along the wall of the eye (the stage). Once the vessels have grown into Zone 3 (see below) it is usually safe to discharge the child from further screening for ROP. The stage of ROP refers to the character of the leading edge of growing retinal blood vessels (at the vascular-avascular border). The stages of ROP disease have been defined by the International Classification of Retinopathy of Prematurity (ICROP).

Retinal examination with scleral depression is generally recommended for patients born before 30–32 weeks gestation, with birthweight 1500 grams or less, or at the discretion of the treating neonatologist. The initial examination is usually performed at 4–6 weeks of life, and then repeated every 1–3 weeks until vascularization is complete (or until disease progression mandates treatment).

In older patients the appearance of the disease is less well described but includes the residua of the ICROP stages as well as secondary retinal responses.