|Primary juvenile glaucoma|
|A child with right eye buphthalmos, developed due to congenital glaucoma.|
Primary juvenile glaucoma is glaucoma that develops due to ocular hypertension and is evident either at birth or within the first few years of life. It is caused due to abnormalities in the anterior chamber angle development that obstruct aqueous outflow in the absence of systemic anomalies or other ocular malformation.
The typical infant who has congenital glaucoma usually is initially referred to an ophthalmologist because of apparent corneal edema. The commonly described triad of epiphora (excessive tearing), blepharospasm and photophobia may be missed until the corneal edema becomes apparent.
JOAG is an autosomal dominant condition. The primary cause is the myocilin protein dysfunction. Myocilin gene mutations are identified in approximately 10% of patients affected by juvenile glaucoma.
The diagnosis is clinical. The intraocular pressure (IOP) can be measured in the office in a conscious swaddled infant using a Tonopen or hand-held Goldmann tonometer. Usually, the IOP in normal infants is in the range of 11-14 mmHg. Buphthalmos and Haab's striae can often be seen in case of congenital glaucoma.
Corneal cloudiness may have myriad of causes. Corneal opacity that results from herary dystrophies is usually symmetric. Corneal enlargement may result from megalocornea, a condition in which the diameter of the cornea is larger than usual and the eye is otherwise normal.
The preferred treatment of congenital glaucoma is surgical, not medical. The initial procedures of choice are goniotomy or trabeculotomy if the cornea is clear, and trabeculectomy ab externo if the cornea is hazy. The success rates are similar for both procedures in patients with clear corneas. Trabeculectomy and shunt procedures should be reserved for those cases in which goniotomy or trabeculotomy has failed. Cyclophotocoagulation is necessary in some intractable cases but should be avoided whenever possible because of its potential adverse effects on the lens and the retina.
In the United States, the incidence of primary congenital glaucoma is about one in 10,000 live births. Worldwide, the incidence ranges from a low of 1:22,000 in Northern Ireland to a high of 1:2,500 in Saudi Arabia and 1:1,250 in Romania. In about two-thirds of cases, it is bilateral. The distribution between males and females varies with geography. In North America and Europe, it is more common in boys, whereas in Japan it is more common in girls.