Ординатура / Офтальмология / Английские материалы / Clinical Pathways in Glaucoma_Zimmerman, Kooner_2001

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Childhood Glaucoma

Kimberly S. Warren and Füsun Gökmen

Definition

How Is Childhood Glaucoma Defined?

Childhood glaucoma is a group of disorders characterized by improper development of the eye’s aqueous outflow system. Another term for this group of disorders is developmental glaucoma. Most developmental glaucomas are seen in childhood. Infantile glaucoma is any glaucoma occurring during the first several years of life, generally accepted as the first 3 years of life. Juvenile glaucoma is a nonspecific term referring to any type of glaucoma occurring in later childhood or the teenage years.

What Is Buphthalmos?

Buphthalmos means “ox eye” in Latin and refers to the marked enlargement of the globe that can result from any type of glaucoma present in infancy. Hydrophthalmia refers to the high fluid content of buphthalmic eyes.

How Is Childhood Glaucoma Classified?

We can divide childhood glaucoma into three major categories (Table 1–1):

(1) primary congenital glaucoma, in which the developmental anomaly is restricted to a maldevelopment of the trabecular meshwork; (2) glaucoma associated with other ocular or systemic congenital anomalies; and (3) secondary glaucoma, which includes acquired ocular diseases that can cause glaucoma.1

4 Childhood Glaucoma

The common defect is believed to arise from a developmental arrest during the third trimester of gestation of tissues derived from neural crest cells. The mechanism by which this developmental defect leads to aqueous outflow obstruction, in some cases, may be a paradoxical collapse of the trabecular meshwork and Schlemm’s canal in response to contraction of the ciliary musculatur, although other patients may have additional developmental abnormalities in the aqueous outflow system as the possible mechanism of glaucoma.6

What Is Barkan’s Membrane?

In 1955 Barkan7 described a persisting fetal membrane overlying the trabecular meshwork. Recent pathologic studies have not found evidence of Barkan’s membrane. This apparent membrane may be due to the observation of thickened, compact trabecular beams in the area of the meshwork.5

What Is the Cause of Elevated IOP

in Congenital Glaucoma?

There is clinical evidence in childhood glaucoma that the obstruction to aqueous flow, with a resultant increase in IOP, is located at the level of trabecular sheets. Schlemm’s canal has been found to be open both histologically and clinically and does not appear to be the site of obstruction to aqueous flow.4,8,9

What Are the Congenital Anomalies Associated with Childhood Glaucomas?

Table 1–1 lists the congenital anomalies associated with childhood glaucoma. Each condition is described below.

What Is the Risk of Developing Glaucoma

in Familial Hypoplasia of the Iris?

This condition is characterized by hypoplasia of the anterior iris stroma, a prominent pupillary sphincter, trabeculodysgenesis, and glaucoma. Glaucoma may occur any time from birth until late adulthood, but eventually will develop in almost 100% of cases. The hereditary pattern is autosomal dominant.10, 11

What Are the Related Conditions

with Anomalous Superficial Iris Vessels?

Irregular superficial iris vessels are generally seen with the distortion or absence of the superficial iris stroma and distortion of the pupil in newborn children with glaucoma. The cornea is usually hazy. These vessels should be differentiated from the normal radial iris vessels, which are straight and have no associated distortion of the iris tissue. Generally this is a bilateral disease.

How Often Is Aniridia Associated with Glaucoma?

Aniridia is a bilateral congenital anomaly characterized by marked hypoplasia of the iris, keratopathy, foveal hypoplasia, cataract, ectopia lentis, and optic

nerve hypoplasia.12 Retardation of psychomotor development also may be evident. Trabeculodysgenesis of the anterior chamber angle or progressive pulling up of the residual iris stump and occlusion of the trabecular meshwork with synechiae formation are the proposed pathologies for the development of glaucoma. In most cases glaucoma does not develop until later childhood and sometimes does not develop at all.

Is Aniridia Hereditary?

Aniridia is most commonly a hereditary disorder transmitted as autosomal dominant. It also can occur sporadically, and approximately 20% of patients are found to have Wilms’ tumor. There is a specific syndrome caused by a partial deletion of the short arm of chromosome 11 and includes aniridia, Wilms’ tumor, mental retardation, and ambiguous genitalia.13

When Is Glaucoma Suspected in Sturge-Weber

Syndrome?

Sturge-Weber syndrome is a flat facial hemangioma that follows the distribution of the fifth cranial nerve. A meningeal hemangioma (which can produce a seizure disorder), choroidal hemangiomas, and episcleral hemangiomas may also be present.14 The glaucoma is present when the facial hemangioma involves the lids or conjunctiva. Facial hemangioma is usually unilateral but may be bilateral. Glaucoma occurs usually in infancy but may not develop until early adulthood in some cases. A combined mechanism of isolated trabeculodysgenesis and elevated episcleral venous pressure presumably plays a role in the pathology.15

When Should Glaucoma Associated with Neurofibromatosis Be Suspected?

Neurofibromatosis (von Recklinghausen’s disease) is an autosomal-dominant disease characterized by multiple café-au-lait spots, neurofibromas of the skin and peripheral and central nervous system, and absence of a portion of the sphenoid bone or other skeletal defects.16 Ocular involvement includes nodules on the iris (Lisch nodules) and eyelids, ectropion uvea, optic nerve gliomas, retinal astrocytic hamartomas, and proptosis resulting from either optic nerve gliomas or herniation of brain tissue into the orbit.

Glaucoma associated with neurofibromatosis generally is seen with neuromas involving the upper eyelid or the eye itself. Isolated trabeculodysgenesis or synechial closure caused by neurofibromatous tissue can be the mechanism of pathology. A sheet of avascular dense tissue may arise from the periphery of the iris and extend anteriorly into the angle.

What Types of Glaucoma May Be Encountered in Patients with Marfan Syndrome?

This syndrome is characterized by arachnodactyly, congenital weakness of the aorta, aortic and mitral valve disease, scoliosis, hypotonia, and ocular abnor-

Rieger’s syndrome is the association of the above ocular abnormalities with systemic abnormalities. Dental and facial anomalies are most common and include hypodentia, microdentia, molar hypoplasia, and hypertelorism. Other systemic anomalies include short stature, heart defects, neurologic problems, empty sella syndrome, deafness and mental deficiency. Glaucoma occurs in approximately 50% of the affected individuals.23

What Are the Features of Peter’s Anomaly?

Peter’s anomaly is manifested as central corneal opacification with adhesions of the central iris to the posterior surface of the cornea. These iris attachments arise from the collarette and attach to the cornea where there is an absence of Descemet’s membrane and thinning of the posterior corneal stroma. In extreme cases the lens may adhere to the corneal endothelium and become cataractous.24

Another term for Peter’s anomaly is anterior chamber cleavage syndrome. Glaucoma occurs in about 50% of the involved eyes anywhere from infancy to later childhood.

What Is Loew’s Syndrome?

Loew’s syndrome is a sex-linked recessive disease characterized by aminoaciduria and mental retardation in male infants. Another term for this group of conditions is oculocerebrorenal syndrome. Ocular abnormalities most commonly are cataracts and glaucoma. Generally, isolated trabeculodysgenesis is observed microscopically.25

How Is Microspherophakia Suspected?

The finding of a small spheric lens whose edges are clearly seen through a middilated pupil may be suspected as microspherophakia. High myopia with shallow chamber in a young person is a characteristic of this entity. Due to the laxity of the zonules, the lens may subluxate in the posterior chamber or move anteriorly, resulting in pupillary block glaucoma.26

What Are the Characteristics of Glaucoma Seen

in Rubella Syndrome?

The glaucoma may be present in infancy and accompanied by features of isolated trabeculodysgenesis. Glaucoma can also result from iridocyclitis. If there is any evidence of inflammation, this mechanism must be suspected. Rubella keratitis causes deep and diffuse corneal clouding, which must not be confused with corneal edema resulting from glaucoma.27

What Are the Chromosomal Anomalies Related to Glaucoma?

Trisomy 21, trisomy 13–15, trisomy 17–18, Turner’s syndrome, and trisomy 2q may be associated with glaucoma.28, 29

8 Childhood Glaucoma

What Is the Mechanism of Glaucoma in Persistent

Hyperplastic Primary Vitreous?

This condition results from failure of atrophy of the primary vitreous and its vascular structures, and typically occurs unilaterally in a microphthalmic eye. A retrolental fibrovascular membrane attached to the posterior lens and ciliary process draws the processes into the pupillary space. Progressive opacification and swelling of the lens may cause angle-closure glaucoma, whereas contraction of the membrane may push the lens forward.

What Are the Common Childhood Secondary Glaucomas?

The common childhood secondary glaucomas are enumerated in Table 1–1. Each condition is discussed below.

When Is Glaucoma Seen in Retinopathy of Prematurity

(Retrolental Fibroplasia)?

Retinopathy of prematurity is associated with a history of prematurity of the newborn. It is bilateral and nearly symmetric. One theory suggests that oxygen therapy causes vasoconstriction in the peripheral retinal vessels initially. Ischemia may invite neovascularization, which may grow through the internal limiting membrane into the vitreous in advanced cases. Eventually, the development of these retrolental fibrotic membranes may cause a forward displacement of the lens and iris and cause angle-closure glaucoma with some degree of pupillary block.30

What Tumors May Cause Glaucoma in Children?

Retinoblastoma is the most common intraocular tumor of childhood. The tumor may invade the iris and trabecular meshwork area. Many patients develop rubeosis iridis and intractable neovascular glaucoma.31 Juvenile xanthogranuloma is an uncommon skin disease with its onset in infancy.32 Ocular involvement is seen as a vascular, yellowish white, solitary or diffuse mass of iris. Tumor involvement of the trabecular meshwork area and ciliary body may also occur. The most common cause for glaucoma is a spontaneous hemorrhage into the anterior chamber.

What Is the Most Common Inflammatory Condition

Present with Glaucoma in Children?

Chronic iridocyclitis seen in juvenile rheumatoid arthritis is rarely associated with discomfort or redness. Many patients with this “white uveitis” may present with sequelae that may include glaucoma, cataracts, and band keratopathy.33 For other causes, see Chapter 8.

Is Traumatic Glaucoma Common in Children?

Children may present with traumatic glaucoma that is very similar to that in adults. For a complete discussion, see Chapter 13.