OPTIC NERVE EXAMINATION The optic nerve, when visible, usually shows increased cupping in PCG. Generalized enlargement of the optic cup in very young patients with glaucoma has been attributed to stretching of the optic canal and backward bowing of the lamina cribrosa (Fig 22-4). In most cases of PCG, the cup–disc ratio exceeds 0.3; in contrast, most normal newborn eyes have a cup–disc ratio of less than 0.3. Cup–disc asymmetry greater than 0.2 between the 2 eyes is also suggestive of glaucoma. In young children, optic nerve cupping may reverse after IOP is lowered. Whenever possible, optic disc photographs should be taken for comparison during later examinations.

Figure 22-4 Optic nerve changes after treatment of congenital glaucoma. A, Preoperative enlarged optic disc cup. B, Reduction in disc cupping after intraocular pressure is reduced by goniotomy. (Courtesy of Sharon Freedman, MD.)

MEASUREMENT OF AXIAL LENGTH Serial measurement of axial length is useful for monitoring disease progression in infant eyes. Excessive growth in an eye, especially compared with the fellow eye, may indicate inadequate IOP control.

OPTICAL COHERENCE TOMOGRAPHY Newer methods of optic nerve and retinal nerve fiber analysis such as optical coherence tomography (OCT) are being evaluated for efficacy in monitoring childhood glaucoma.

Natural history

Untreated PCG almost always progresses to blindness. The cornea irreversibly opacifies and may vascularize. It may continue to enlarge through the first 2–3 years of life, reaching a diameter of up to 17 mm. As the entire eye enlarges, pseudoproptosis and an “ox eye” appearance (buphthalmos) may result. Scleral thinning and myopic fundus changes may occur, and spontaneous lens dislocation can result. Optic nerve damage progresses, leading to complete blindness.

Juvenile Open-Angle Glaucoma

JOAG is an autosomal dominant condition that presents after 4 years of age. Unlike in laterecognized PCG, the cornea is not enlarged, Haab striae are not present, and the anterior chamber angle usually appears normal. Management is similar to that of adult primary open-angle glaucoma, but the condition frequently requires surgery.