Oftalmologia Pediátrica e Estrabismo

Paediatric glaucoma

Definition

Paediatric glaucoma is a rare disease with several possible causes, but the final mechanism of the disease is equal in all its forms.

Based on the cause, there are three main types of paediatric glaucoma:

1. Primary congenital glaucoma: caused by a disorder in the development of the trabecular meshwork. This type of glaucoma is not associated with any other disease.

2. Glaucoma associated with other congenital alterations, systemic or ocular:

2.1 Examples of systemic diseases associated with paediatric glaucoma:
Sturge – Weber’s syndrome, neurofibromatosis, Marfan’s syndrome, homocystinuria, Lowe’s syndrome.

2.2 Examples of eye diseases associated with paediatric glaucoma:
Axenfeld – Rieger’s syndrome, Peters’ disorder, aniridia.

3. Glaucoma associated with other ocular alterations such as inflammation,
trauma or tumours. Examples: glaucoma related to severe cicatricial retinopathy of prematurity, foetal vascularization persistence, tumours as the retinoblastoma, uveitis, ocular traumatisms and aphakia.


Primary congenital glaucoma


Prevalence

It is rare in spite of being the most common type of congenital glaucoma. It affects 1 in every 10,000 children. In Europe and in the United States of America, it is more frequent in male individuals who represent 65% of the cases. In 70% of the cases it is bilateral.

Heredity


Most of the cases are sporadic. About 10% are familial, generally with recessive autosomal transmission, with a penetration varying between 40% and 100%. There are three identified loci related to this disease: GLC3A, GLC3B and GLC3C.

Age for diagnosis

The age for diagnosis ranges from birth to late childhood. In 40% of the cases there exists prenatal ocular hypertension and clinical signs are present at birth, with oedema and increase of the cornea diameter. This clinical frame is considered the real “congenital glaucoma”.
The start of signs and symptoms occurs in 60% of the cases during the first 6 months of life and in 86% of the cases during the 1st year. When the disease appears during this period of life, it is named babyhood glaucoma.
The designations of infantile and juvenile glaucoma concern the cases in which the disease appears later: between the 1st and the 4th year of life, and after the 4th year, respectively.

Clinical signs

They depend on the particular characteristics of the child’s eyeball and they vary according to the age at disease onset, the rapidity of increase of ocular pressure and the value of the pressure.

> Turbidity and increase of the cornea diameter: frequently the first signs of congenital glaucoma resulting from the increase of ocular pressure. The weak rigidity of the cornea eases its widening and the distension of the rim. A fast and strong increase of ocular pressure causes corneal oedema producing a turbid appearance.

> Lachrymation, photophobia and blepharospasms: the first symptoms and a consequence of the oedema and turbidity of the cornea.

> Buffthalmos: it means enlargement of the eye. It is a consequence of the increase of ocular pressure during the first 3 years of life. It is due to the weak rigidity of the sclera, which suffers a stretching and a thinning and sometimes shows a bluish appearance caused by the colour of the underlying choroid coat.

> Myopia: caused by the increase of the axial length of the eye.

> Amblyopia: it can be caused by the turbidity of the cornea or by myopia resulting from the increase of the axial length of the eye.

> Rupture of the Descemet’s membrane: these ruptures, known as Haab’s striae, are a result of the decompensation of the corneal endothelium, with sudden flowing of liquid into the corneal stroma. These alterations of the cornea can cause astigmatism in the affected eyes.

> Papillary pit: it may develop precociously, but unlike in adults, it may regress. The scleral channel may enlarge with high pressures, as part of the general enlargement of the eyeball.

Diagnosis

The diagnosis is made by the ophthalmologist, based on the alterations of the cornea (appearance and diameter), the measurement of ocular pressure and the examination of the papilla.
The paediatrician should suspect of the existence of congenital glaucoma whenever he observes a cornea with increased diameter or turbid appearance (especially when accompanied by photophobia and blepharospasm).

Treatment

Congenital glaucoma is treated through surgery. There are three main techniques: goniotomy, trabeculotomy and trabeculectomy. In more serious cases, with recurrence, it may be necessary to resort to more complex techniques, with the insertion of a draining valvular apparatus. Unlike the procedure in adult glaucoma, medical treatment with drops is only adequate initially, to precociously lower ocular pressure and to reduce the turbidity of the cornea. In case of recurrence, it is useful to save time until a new surgery.

 

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