Table 6-3
Since PCG is a relatively rare disease, primary care doctors and general ophthalmologists may never have seen a case. Milder cases have fewer signs and symptoms and may be misdiagnosed as nasolacrimal duct obstruction; this misdiagnosis results in delayed diagnosis and irreversible damage (see Table 6-3). Physicians must be vigilant about adequately assessing and referring infants who present with the classic triad of epiphora, photophobia, and blepharospasm. Left untreated, almost all cases of PCG will progress to blindness.
Treatment of PCG typically requires surgical intervention, which is discussed later in this chapter (see the section Surgical Management). Medical therapy has limited long-term value but may be used to temporize or reduce corneal edema to improve visualization during surgery.
Walton DS, Katavounidou G. Newborn primary congenital glaucoma: 2005 update. J Pediatr Ophthalmol Strabismus. 2005;42(6):333–341.
Juvenile Open-Angle Glaucoma
Juvenile open-angle glaucoma (JOAG) is a form of primary open-angle glaucoma that presents with elevated IOP between the ages of 4 and 35. Since most cases of JOAG are inherited as an autosomal dominant trait, many families may be aware of their risk of developing this condition, leading to earlier screening and detection. Although the IOP is elevated, it does not usually cause corneal enlargement or Haab striae; rather, progressive myopia may continue to develop until 10 years of age. The angles appear normal. Medical therapy is usually unsuccessful, and most patients require trabeculectomy or implantation of a glaucoma drainage device. Angle procedures may be helpful in select cases.
Developmental Glaucomas of Childhood With Associated Ocular or Systemic Anomalies
The childhood glaucomas may be associated with various ocular and systemic abnormalities, as summarized in Tables 6-1 and 6-2. Following are discussions of the more common of these conditions.
Axenfeld-Rieger Syndrome
Axenfeld-Rieger (A-R) syndrome is a spectrum of disorders characterized by bilateral anomalous development of the neural crest–derived anterior segment structures. Affected structures include the anterior chamber angle, the iris, and the trabecular meshwork. Autosomal dominant inheritance occurs in most cases, but A-R syndrome can also occur sporadically. Approximately 50% of cases are associated with glaucoma that usually develops in middle or late childhood.
Although this syndrome was initially separated into Axenfeld anomaly (posterior embryotoxon with multiple adherent peripheral iris strands), Rieger anomaly (Axenfeld anomaly plus iris hypoplasia and corectopia), and Rieger syndrome (Rieger anomaly plus developmental defects of the teeth or facial bones, including maxillary hypoplasia, redundant periumbilical skin, pituitary abnormalities, or hypospadias), these disorders are now considered variations of the same clinical entity and are combined under the name Axenfeld-Rieger syndrome.
The typical corneal abnormality is a posterior embryotoxon (a prominent and anteriorly displaced Schwalbe line), with the remainder of the cornea being normal. Iridocorneal adhesions to the Schwalbe line range from threadlike to broad bands of iris tissue. The iris itself may range from normal to markedly atrophic with corectopia, hole formation, and ectropion uveae. The disorder is bilateral, with no sex predilection. A-R syndrome can be distinguished from other conditions that involve abnormalities of the iris, cornea, and anterior chamber, as outlined in Table 6-4.
Table 6-4
Peters Anomaly
Peters anomaly is a developmental condition presenting with an annular corneal opacity (leukoma) in the central visual axis. The leukoma corresponds to a defect in the corneal endothelium and underlying Descemet membrane and posterior stroma. Typically, there are adhesions between iris strands, and these strands extend from the collarette to the corneal opacity. The lens may be in its normal position, with or without a cataract, or the lens may be adherent to the posterior layers of the cornea. Patients with corneolenticular adhesions have a higher likelihood of ocular abnormalities, such as microcornea and angle anomalies, and of systemic abnormalities, including those of the heart, genitourinary tract, musculoskeletal system, ear, palate, and spine.
Peters anomaly is usually sporadic, although autosomal dominant and autosomal recessive forms have been reported. The majority of cases are bilateral, and angle abnormalities cause glaucoma in approximately 50% of affected patients.
The glaucoma associated with Peters anomaly is very difficult to treat because of the iridocorneal dysgenesis. Angle surgery is performed if possible; alternative treatments include medications, trabeculectomy, glaucoma drainage devices, and cyclodestructive procedures.
Aniridia
Aniridia is a bilateral congenital disorder characterized by iris hypoplasia. Most patients with aniridia have only a rudimentary stump of iris; however, the iris appearance may vary greatly, with some patients having nearly complete but thin irides. Aniridia is often associated with other ocular anomalies, including small corneas, cataracts that may be present at birth or develop later in life, and optic nerve and foveal hypoplasia with resulting pendular nystagmus and reduced vision.
Approximately 50%–75% of patients with aniridia develop glaucoma. Though occasionally associated with congenital glaucoma, glaucoma in aniridia usually develops after the rudimentary iris stump rotates anteriorly to progressively cover the trabecular meshwork, resulting in synechial angle closure. This is a gradual process, and glaucoma may not occur until the second decade of life or later. Primary maldevelopment of the drainage angle may also result in elevated IOP at a younger age.
Patients with aniridia may have limbal stem cell abnormalities that eventually result in a corneal pannus, which begins in the peripheral cornea and slowly extends centrally. There may be a role for limbal stem cell transplants in these patients.
Most cases of aniridia are familial and are transmitted with an autosomal dominant inheritance pattern; however, about one-third of cases are isolated sporadic mutations. Approximately 20% of sporadic cases are associated with a large chromosomal deletion that includes the Wilms tumor 1 gene (WT1), a tumor suppressor gene, which results in an increased risk of Wilms tumor; relatively few cases of Wilms tumor are seen in the familial form.
There are 2 less common forms of aniridia that are associated with systemic abnormalities. WAGR (Wilms tumor, aniridia, genitourinary anomalies, and mental retardation) syndrome is an autosomal dominant form seen in 13% of patients with aniridia. Gillespie syndrome, an autosomal recessive form of aniridia, is associated with cerebellar ataxia and intellectual disability and occurs in 2% of those with aniridia.
Prophylactic goniosurgery in infants with a strong family history of aniridic glaucoma may be beneficial. Young children with progressive angle narrowing may also benefit from goniosurgery if the angle is not fully closed. Once the angle is closed, trabeculectomy, glaucoma drainage devices, and cyclophotocoagulation may be required for long-term control. Thus, it is important to closely follow the angle anatomy with serial gonioscopy.
Sturge-Weber Syndrome
Sturge-Weber syndrome (also known as encephalotrigeminal angiomatosis) is a phakomatosis with ipsilateral facial cutaneous hemangioma (nevus flammeus or port-wine stain), ipsilateral cavernous hemangioma of the choroid, and ipsilateral leptomeningeal angioma. The condition is usually unilateral but can present bilaterally in rare instances. There is no race or sex predilection, and no inheritance pattern has been established. Glaucoma occurs in 30%–70% of children with this syndrome and is more common when the nevus flammeus involves the eyelids. When seen in infants with this syndrome, the glaucoma is thought to be due to congenital anterior chamber anomalies (similar to congenital glaucoma). Elevated episcleral venous pressure may be involved in glaucoma that develops after the first decade of life. Involvement of the central nervous system may cause seizures, focal neurological defects, or intellectual disability. Trabeculectomy should be performed with caution in patients with Sturge-Weber syndrome because their risk of choroidal effusion and choroidal hemorrhage is substantially increased.
Neurofibromatosis
Neurofibromatosis (NF) is the most common phakomatosis. Two forms of NF are recognized.