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Primary congenital glaucoma: causes, symptoms, diagnosis, treatment
Last reviewed: 25.06.2018
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Congenital glaucoma is a group of conditions with anomalies in the development of the system of outflow of intraocular moisture. This group includes: congenital glaucoma, in which an anomaly in the development of the anterior chamber angle is not associated with other ocular or systemic abnormalities; Congenital glaucoma with concomitant ocular or systemic abnormalities; secondary glaucoma of childhood, in which other eye pathologies cause a violation of outflow of fluid.
To classify congenital glaucoma, several different approaches are used. Most often used anatomical classification of Schaeffer-Weiss and Hoskin. The Sheffer-Weiss classification distinguishes three main groups: primary congenital glaucoma; glaucoma, associated with congenital anomalies; secondary glaucoma of childhood. The second classification is based on developmental abnormalities that are clinically determined during the examination, and also includes three groups: an isolated disruption of the development of the trabecular apparatus with malformations of the trabecular network without anomalies of the iris and the cornea; iridotrabecular dysgenesis, including anomalies of the angle and iris; corneal trabecular dysgenesis, often associated with anomalies of the iris. The definition of anatomical defects can be useful for determining the tactics of treatment and prognosis.
Primary congenital glaucoma is the most common form of childhood glaucoma, accounting for approximately 50% of all cases of congenital glaucoma. It is characterized by anomalies in the development of the trabecular network, the lack of communication with other eye and systemic diseases. In 75% of cases, primary congenital glaucoma affects both eyes. The incidence is 1 per 5000-10000 live births. More than 80% of cases occur before the age of 1 year: 40% - immediately after birth, 70% - at the age of 1 to 6 months and 80% - up to 1 year. Pathology is more common in boys (70% in boys, 30% in girls), in 90% cases are sporadic, there is no family history. Despite the development of an autosomal recessive model with variable penetrance, it is believed that most cases are the result of multifactorial inheritance involving non-genetic factors (eg, environmental factors).
[Symptoms of primary congenital glaucoma
Anamnesis
Lachrymation, photophobia and blepharospasm form a classical triad. Usually, children with congenital glaucoma prefer a semi-darkness and avoid being in the bright light. Mark excessive lacrimation. In the case of a one-sided lesion, the mother may notice asymmetry in the eyes of the child, an increase (the affected side) or a decrease (the normal side) of the size of the eyes.
Exterior inspection
The normal horizontal diameter of the cornea in full-term newborns is 10-10.5 mm. It increases to an adult size (approximately 11.5-12 mm), to two years. The diameter of the cornea in the newborn more than 12 mm indicates a high probability of congenital glaucoma.
Corneal opacities, descemet membrane ruptures (Haab striae), deep anterior chamber, intraocular pressure above 21 mm Hg, hypoplasia of the iris stroma, isolated trabeculodysgenesis in gonioscopy, an increase in the excavation of the optic nerve disk can also be detected. The Haab strata can be single or multiple, they are usually oriented horizontally or concentrically to the limb.
Evaluation of the optic nerve disc is a key moment in the diagnosis of glaucoma. Glaucomatous disc changes occur in infants faster and against a background of lower intraocular pressure than in adolescents and adults. The ratio of excavation area to the area of the optic nerve disk is more than 0.3 in normal infants rarely, indicating a high probability of glaucoma development. The same is evidenced by the asymmetry of wheel excavations, especially the difference of more than 0.2 between two eyes. Glaucomatous excavation in form can be oval, but more often it is round, located in the center. After normalization of intraocular pressure, the recovery of the excavation to the initial state is observed.
To establish an accurate diagnosis and the appointment of an adequate treatment, it is necessary to assess the angle of the anterior chamber of the eye. Developmental anomalies can be present in two basic forms: a flat attachment of the iris, in which the iris is attached directly or anteriorly from the trabecular network, its processes can be thrown over the scleral spur, and the convex attachment of the iris, in which it is visible behind the trabecular network, but covered with a dense an abnormal tissue. For comparison, a photograph of the gonioscopic picture of the normal angle of the baby's anterior chamber is presented.
An increase in intraocular pressure leads to a strong increase in the eyeball with a progressive thickening of the cornea in children under 3 years of age. With the increase in the cornea, its stretching leads to rupture of the descemet membrane, edema of the epithelium and stroma, and also to the opacity of the cornea. The stretching of the iris leads to a thinning of the stroma. The scleral canal through which the optic nerve passes also increases with increasing intraocular pressure, which leads to a rapid increase in the excavation of the optic nerve disc, which quickly returns to its original state with the normalization of intraocular pressure. In adults, such rapid recovery of excavation size does not happen, probably because of the greater elasticity of the connective tissue of the nipple of the optic nerve in infants. If intraocular pressure can not be controlled, a bufalm can develop.
Differential diagnosis of primary congenital glaucoma
The changes in the cornea also include megalocornea, metabolic diseases, corneal dystrophy, birth trauma and keratitis. Lachrymation or photophobia can occur with obstruction of nasolacrimal pathways, dacryocystitis and iritis. Changes in the optic nerve, like changes in glaucoma, include pits of the optic nerve disk, colobomas and hypoplasia.
Treatment of primary congenital glaucoma
Congenital glaucoma is always treated surgically. Drug treatment can be used for a limited period of time - before the appointment of an operation. The method of choice for such conditions is trabecular incisions. With goniotomy, a transparent cornea is required to visualize the anterior chamber angle. Goniotomy is performed with the help of goniotoma and direct goniolinase, goranoliza Barkan is preferred. Using a goniot, the incision is made in a dense anomalous tissue on the trabecular nerve network from 90 to 180 ° through a transparent cornea (Figures 10-7 and 10-8). Trabeculotomy with external access to the helmet canal does not require transparency of the cornea.
When the cornea is clouded, trabeculotomy is indicated. Form a scleral flap in which it is necessary to detect the helmets channel for the procedure. The trabecular network is cut using a trabeculotomy or using a suture (usually propylene), a channel through the helmets (the Lynch method). If the helmet canal can not be detected, a trabeculectomy is performed. Another treatment option for such patients is the installation of valvular or valveless draining devices.