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Describe congenital glaucoma with its features and management.

Ophthalmology · 3rd Professional

Nature and Presentation

Primary congenital glaucoma (buphthalmos) results from an isolated maldevelopment of the angle (trabeculodysgenesis), obstructing aqueous outflow in an eye whose coats are still distensible, so that the whole globe enlarges — the "ox eye".

Inheritance — autosomal recessive with incomplete penetrance, associated with CYP1B1 mutations. consanguinity is a major factor in India, and the family history must be asked for directly
Epidemiology — about 65% are male; 70% are bilateral, though often asymmetrical; and 40% present at birth, with most of the remainder in the first year

Sign	Detail
Buphthalmos — corneal enlargement	Normal horizontal corneal diameter is 10 to 10.5 mm at birth and 11.5 mm at one year. A diameter above 12 mm in the first year is abnormal, and asymmetry between the eyes of more than 0.5 mm is significant
Corneal oedema and haze	From pressure-driven fluid entry; it is the cause of the photophobia and the presenting appearance
HAAB’S striae	Horizontal or curvilinear breaks in descemet membrane with rolled edges, caused by corneal stretching. They are permanent and are the key distinction from birth trauma by forceps, in which the Descemet tears are vertical or oblique
Raised intraocular pressure	Normal in an infant is 10 to 12 mmHg, so a pressure over 20 is clearly abnormal. Most anaesthetics lower it and ketamine raises it.
Deep anterior chamber and a stretched limbus	With a blue-grey appearance of the thinned sclera
Optic disc cupping	Occurs early and progresses fast; but uniquely in infants it may reverse once the pressure is controlled.
Refractive consequences	Axial myopia and astigmatism from the enlarging globe, with anisometropic and deprivation amblyopia
Late	Lens subluxation from stretched zonules, and retinal detachment

Differential Diagnosis and Assessment

Causes of a large cornea — megalocornea.
Causes of a cloudy cornea in infancy — the mnemonic stumped: Sclerocornea; Tears in Descemet (birth trauma, with vertical striae, or glaucoma with horizontal ones); Ulcer and infection; Metabolic disease (mucopolysaccharidoses, which cause diffuse haze); Peters anomaly; Endothelial dystrophy (congenital hereditary endothelial dystrophy); and Dermoid
Secondary and associated childhood glaucomas — axenfeld-RIEGER anomaly (posterior embryotoxon, iris strands, corectopia, with dental and umbilical anomalies); PETERS anomaly; aniridia; STURGE-WEBER syndrome; neurofibromatosis; homocystinuria and Marfan with lens subluxation; retinopathy of prematurity; and glaucoma after paediatric cataract surgery, which is common, may appear years later and is a major cause of late visual loss

Treatment and Applied Aspects

The treatment IS surgical. Medical treatment is only a temporising measure to clear the cornea before operating; it does not control the disease
Goniotomy — an internal incision of the trabecular meshwork under direct gonioscopic view. It requires a clear cornea, and is the procedure of choice where the view allows
Trabeculotomy — an external approach in which Schlemm canal is identified and a probe rotated into the anterior chamber. Its advantage is that it does not need a clear cornea, so it is used where there is oedema — which is most Indian presentations

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