GLAUCOMA
Glaucoma, i.e. raised intraocular pressure, is an important cause of visual impairment due to secondary pressure effects on optic nerve. Unlike adults, childhood glaucoma is almost always caused by defective drainage of aqueous fluid.
Etiologically, it may be classified as congenital glaucoma due to anatomical abnormalities of the trabecular drainage network; and Secondary glaucoma due to post- traumatic or post-inflammatory obstructive lesions (Table 26.9). However, even congenital glaucoma may not be evident at birth and develops after many weeks.
TABLE 26.9: Causes of glaucoma in children
Congenital glaucoma (gt;50%)
• Intrauterine infections: Congenital Rubella
• Chromosomal disorders: Down syndrome
• Genetic disorders: MPS, Homocystinuria
• Connective tissue defects: Marfan syndrome
• Neurocutaneous syndromes
Secondary glaucoma
• Injury: Trauma to ciliary body
• Indammations: Iridocyclitis
• Intraocular hemorrhage
• Intraocular tumors
• Iatrogenic: Prolonged steroid therapy
MPS: Mucopolysaccharoidosis
Other ocular abnormalities, e.g. aniridia, cataracts, spherophakia and ectopia lentis are commonly associated in congenital glaucoma.
Clinically, glaucoma presents with a triad of: (a) epiphora, (b) photophobia, and (c) blepharospasm, with or without vision impairment. Examination may reveal circumciliary congestion (red-eye), corneal edema and/ or enlargement (Buphthalmos) and raised intraocular pressure on tonometry. Buphthalmos is only seen in congenital glaucoma, when cornea is still stretchable and may lead to breaks in Descemet's membrane (Haab's striae) with residual corneal scarring.
Diagnosis rests on tonometry, which may require anesthesia in very young children.
Treatment is surgical in most cases, involving procedures to facilitate aqueous drainage (goniotomy or trabeculotomy) and/or to reduce its production (cyclocryotherapy or photocoagulation).
Prognosis depends on the cause, severity and damage at the time of diagnosis. Some visual impairment is common in most cases due to corneal scarring, amblyopia and pressure damage to optic disc.
26.2.10