Definition of Narrow Angle Glaucoma
Narrow angle glaucoma is a group of glaucomas in which the intraocular pressure (eye pressure) is raised as a result of obstruction of the drainage pathway (trabecular meshwork). The obstruction may be mechanical with no evident pathology or it may be because of scarring in the angle where the trabecular meshwork resides.
Narrow angle glaucoma is also called angle closure glaucoma.
How Narrow Angle Glaucoma Affects Vision
Angle is a space in the eye formed between the cornea in the front and iris on the back. The fluid (aqueous) which is formed in the eye constantly drains into trabecular meshwork situated in the angle. Any partial or complete obstruction of the angle compromises the drainage of aqueous. This gives rise to accumulation of the fluid and high eye pressure consequently.
High pressure causes damage to delicate structures of the eye especially the nerve fibers. All the nerve fibers join to form optic nerve which transmits visual information to the brain. Damage to the optic nerve gradually leads to loss of peripheral vision first and then advances to central vision in the late stages.
Angle closure glaucoma is common among women. Other risk factors associated with narrow angle glaucoma are Chinese ethnicity, age more than 60 years, family history (it is hereditary), small eyes, some medications (anticholinergic and adrenergic) and emotional stress.
Narrow Angle Glaucoma Symptoms
- Acute angle closure glaucoma: The patient may have sudden pain, clouded vision, intolerance to bright light, colored halos around lights, headache, nausea and vomiting.
- Subacute angle closure glaucoma: Headache may occur or the person may be asymptomatic.
- Chronic angle closure glaucoma: The patient is largely without any symptoms.
Narrow Angle Glaucoma is more common that formerly thought. The loss of vision is more severe than what is caused by open angle glaucoma. Early diagnosis and treatment (with medication, laser and/or surgery) of narrow angle glaucoma is the key to prevent blindness and related morbidity.