Glaucoma in children

Glaucoma is a pathology that is rarely encountered in childhood. Childhood glaucoma unites a large group of various diseases. Most forms of childhood glaucoma are the result of malformations of the anterior segment of the eye and structures of the anterior chamber angle.

Regardless of the pathophysiological mechanism, most forms of the disease have similar clinical symptoms, which, as a rule, differ significantly from glaucoma in adults.

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Symptoms of Glaucoma

Enlargement of the eyeball

Children's sclera and cornea are less rigid, more elastic and stretchable than those of adults. High intraocular pressure in many cases leads to stretching of the eyeball and thinning of the outer shell of the eye. These changes rarely occur in glaucoma that develops after the age of 2.

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Corneal changes

The corneal epithelium and stroma easily tolerate the increase in its diameter, but the Descemet membrane and endothelium are much worse. As the corneal stretching progresses, ruptures (Haab's striae) occur in the Descemet membrane, located concentrically or linearly. As a result of such changes, corneal edema may occur. Most symptoms of infantile glaucoma (glaucoma of early childhood) are a consequence of corneal edema.

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Photophobia and lacrimation

Apparently, photophobia accompanies the clouding and increase in diameter of the cornea. Pronounced lacrimation in some cases imitates obstruction of the nasolacrimal canal.

Optic disc excavation

In infantile glaucoma, as in older patients, excavation of the optic nerve disc occurs. However, in childhood, excavation may be reversible; the degree of excavation of the optic nerve disc in children is not an accurate prognostic sign.

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Refractive changes and strabismus

Stretching of the cornea and sclera leads to significant refractive errors. Timely correction of these errors is important for the prevention of amblyopia. Strabismus, especially in cases of asymmetric glaucoma, also provokes the development of amblyopia. If the refraction shifts towards myopia in a child with aphakia, concomitant glaucoma should be excluded.

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Primary congenital glaucoma

Primary congenital glaucoma (trabeculodysgenesis: primary infantile glaucoma) is the most common form of childhood glaucoma, occurring in 1 in 10,000 live births. The disease is usually bilateral, but asymmetrical and even unilateral forms occur. In the United States and England, it is more common in boys than in girls, but in Japan the opposite is true. In Europe and North America, inheritance is polygenic or multifactorial. In the Middle East, it is inherited in an autosomal recessive manner.

Gonioscopy reveals a number of features.

1. Iris attachment anomalies:
   • flat attachment of the iris to the trabecular zone anterior or posterior to the scleral spur.
   • concave attachment of the iris where the surface of its root shows above the trabecular meshwork, adjacent to the ciliary body and scleral spur.
2. Absence or rudiment of scleral spur.
3. Very wide, stretched anterior chamber angle.
4. Absence of visible pathology of the Schlemm's canal.
5. Sometimes pathological changes in the iris are detected.

6. Amorphous tissues with vessels passing from the iris to the Schwalbe ring (Barkan's membrane). Goniotomy or trabeculotomy are common primary surgical interventions aimed at reducing intraocular pressure.

Axenfeld-Rieger syndrome

When describing a pathologically compacted and anteriorly displaced Schwalbe ring, the term "posterior embryotaxon" is used. Axenfeld-Rieger syndrome is accompanied by:

• iridocorneal adhesions;
• high attachment of the iris to the trabecula, with coverage of the scleral spur;
• Iris defects include stromal thinning, atrophy, ectopia pupillae, and choroidal ectropion.

Glaucoma occurs in approximately 60% of people with the disease.

Rieger's syndrome

When systemic pathology is accompanied by the above-mentioned changes in the eyeball, the term "Rieger's syndrome" is used. The general pathology in this syndrome includes:

• hypoplasia of the midline of the face;
• telecanthus with a wide, flat root of the nose;
• dental anomaly - absence of maxillary incisors, microdontia, anodontia;
• umbilical hernia;
• congenital heart defects;
• conductive hearing loss;
• mental retardation;
• cerebellar hypoplasia.

Although the autosomal dominant inheritance of this disease has been established, the genetic defect has not yet been identified. There are reports of abnormalities of chromosomes 4, 6, 11, and 18 in Rieger syndrome.

Aniridia

A rare congenital bilateral anomaly that occurs in various forms: sporadic and inherited in an autosomal dominant manner. Glaucoma occurs in 50% of individuals. The pathomorphology of glaucoma has various manifestations. In some cases, the anterior chamber angle is free of goniosynechiae, while in others, progressive development of synechiae can lead to secondary closed-angle glaucoma.

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Syndromes Including Childhood Glaucoma

Some congenital diseases involve defects in the anterior segment of the eyeball, including the anterior chamber angle, iris, and lens. In some cases, these disorders lead to glaucoma.

Sturge-Weber syndrome (facial angioma)

This syndrome includes the classic triad:

1. purple telangiectasias of the face;
2. intracranial angiomas;
3. glaucoma.

Glaucoma, almost always unilateral, is diagnosed in approximately 1/3 of patients with Sturge-Weber syndrome. It may manifest itself at an early age, but in many cases it manifests in older children. The pathophysiology of the disease is diverse and is associated with the development of the same disorders as in congenital glaucoma - increased episcleral venous pressure, premature aging of the structures of the anterior chamber angle. In addition, the possibility of the formation of choroidal hemangiomas increases the risk of damage to the choroid or hemorrhagic complications during intraocular surgery. The disease occurs sporadically, there are isolated reports of familial cases.

Marbling of the skin in congenital telangiectasias

A rare syndrome that is similar in many ways to Sturge-Weber syndrome. It involves vascular disorders associated with skin lesions and includes mottled skin, episodic seizures, strokes, and glaucoma.

Neurofibromatosis

Glaucoma may occur in neurofibromatosis type I. It is often associated with ipsilateral coloboma of the iris or eyelid and plexiform neuromas of the orbit. The etiology of the process is associated with a combination of factors, including both pathology of the tissues of the anterior chamber angle and closure of the angle caused by neurofibromatosis.

Rubinstein-Taybi syndrome

A rare syndrome characterized by hypertelorism, antimongoloid slant of the eyes, ptosis, elongated eyelashes, broad fingers, and enlarged toes. Glaucoma is likely due to underdevelopment of the anterior chamber angle.

Peters Anomaly

Peters anomaly is described as a congenital central corneal opacity associated with stromal, Descemet's membrane, and endothelial defects. Glaucoma in Peters anomaly may be present from birth or may develop after penetrating keratoplasty.

Juvenile open-angle glaucoma

This form of glaucoma, inherited in an autosomal dominant manner, is rare. A link to lq markers has been noted. Clinical examination is uninformative; gonioscopy does not reveal pathology of the anterior chamber angle. Histological examination reveals isolated pathology of the trabecular meshwork.

Secondary glaucoma

Aphakic glaucoma

In patients who underwent cataract extraction in childhood, this form of glaucoma occurs with a frequency of 20-30%. The disease may begin many years after surgery. The pathogenesis is not completely clear, although in some cases it is associated with the development of pathological changes in the angle of the anterior chamber. Some sources associate aphakic glaucoma with certain types of cataracts, including nuclear cataracts and persistent vitreous hyperplasia (PVH). An important risk factor is microphthalmos. The extent to which the surgical intervention itself is responsible for the occurrence of glaucoma is unknown. The disease is difficult to treat and has an unfavorable prognosis.

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Retinopathy of prematurity

Glaucoma may occur in severe retinopathy of prematurity, characterized by total retinal damage. The mechanism of the disorder is multifactorial, including neovascularization, angle closure, and pupillary block.

Pathology of the lens and its interaction with the iris diaphragm

Patients with spherophakia (small spherical lens) are prone to anterior displacement of the lens and the development of glaucoma. The disease can manifest itself both in isolated spherophakia and in the symptom complex of Weil-Marchesani syndrome. In homocystinuria, despite the fact that the lenses are of normal size, they are also prone to anterior dislocation and the development of glaucoma.

Juvenile xanthogranuloma

Juvenile xanthogranuloma is a benign condition that often occurs in the skin and less commonly as an intraocular process that can lead to glaucoma. Glaucoma is usually a consequence of hemorrhage.

Glaucoma in inflammatory eye diseases

Glaucoma may occur as a result of uveitis. Treatment is aimed at suppressing inflammation. Acute trabeculitis or blockage of the trabecular meshwork by exudate in some cases also leads to the development of glaucoma.

Injury

Glaucoma associated with blunt trauma to the eyeball occurs when:

• hyphema (blood blocks the trabecular meshwork);
• angle recession (characteristic of late onset of glaucoma).

Classification of glaucoma

None of the existing classifications of childhood glaucoma are satisfactory. In most classifications, glaucoma is divided into primary and secondary. In primary glaucoma, the increase in intraocular pressure is caused by a congenital disorder of the outflow of intraocular fluid. In contrast, secondary glaucoma develops against the background of a pathological process in other parts of the eyeball or a systemic disease. This chapter uses an anatomical classification based on that proposed by Hoskins (D. Hoskins)

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Diagnosis of childhood glaucoma

The decrease in visual acuity in these patients is caused by damage to the optic nerve, corneal opacity, cataracts and amblyopia. The problems of amblyopia should not be overly exaggerated, it often remains undetected. With timely prescribed plsoptic treatment, visual acuity can improve.

Many standard methods of examination of adults cannot be used in small children in outpatient settings. Computer perimetry and tonometry in outpatient settings are difficult to perform in preschool children, and scars and corneal opacities complicate examination of the optic nerve. Often, for a complete diagnostic examination of a child with glaucoma, it is necessary to use anesthesia.

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Drug treatment of glaucoma

In many forms of childhood glaucoma, conservative treatment is ineffective. It is usually prescribed as an attempt to stabilize intraocular pressure before surgery. A common combination is oral or intravenous acetazolamide with betaxalol and pilocarpine. The doses used vary but should be strictly based on the kg of body weight.

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Glaucoma surgeries

Many surgical interventions have been developed to treat childhood glaucoma.

Goniotomy

The operation is particularly effective in cases of trabeculodysgenesis, but requires a clear cornea. Corneal tears can obscure the view, and in such cases a trabeculotomy is performed.

Anesthesia-guided study of young patients with glaucoma

Anesthetics or sedatives

Anesthesia or sedation are not always necessary when examining newborns. Ketamine, suxamethonium, and intubation can increase intraocular pressure. Halothane and many other drugs decrease intraocular pressure.

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Measured parameters

1. Intraocular pressure is measured immediately after induction of anesthesia. In any case, not being accurate and reliable, tonometry under anesthesia cannot serve as the only criterion for assessing the glaucomatous process.
2. The horizontal and vertical diameter of the cornea from limbus to limbus. Measurement is difficult in significantly enlarged eyes and when the limbus is not clearly defined.
3. Examination of the cornea for the presence of ruptures of the Descemet membrane and to assess its overall transparency.
4. Refraction: Progression of myopia may reflect an increase in eye size.
5. Study of the size of the eyeball using ultrasound.
6. Examination of the optic nerve disc, assessment of the ratio of the excavation diameter to the optic nerve disc, and the condition of the disc boundaries.

* It is preferable to ignore previous research data when making a diagnosis in order to avoid biased judgments.

Yttrium Aluminum Garnet (YAG) Laser Goniotomy

Whether this procedure results in longer-term compensation of intraocular pressure compared to surgical goniotomy is still unknown.

Trabeculotomy

It is the operation of choice in the treatment of primary congenital glaucoma when a good view of the anterior chamber angle is not possible.

Combination trabeculotomy-trabeculectomy

This procedure is especially useful when anterior chamber angle pathology is combined with other intraocular anomalies.

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Trabeculectomy

In young patients, filtration pads are rare. The use of 5-fluorouracil (5-FU), mitomycin, and local radiation therapy increases the duration of filtration pads.

Cyclocryotherapy

Destruction of the ciliary body, which produces intraocular fluid, is resorted to in cases where other surgical interventions have not produced the expected effect.

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Endolaser

The use of endolaser gives good results.

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Drainage implantation

Currently, a wide variety of tubular drains are used for implantation. They are usually not used during primary surgery, but only in cases where the previous operation was ineffective. After improvements in drain models and surgical techniques, serious complications such as hypotension have been reduced.