Sheeza Basharatalmost 2 years ago

Acute Angle Closure Glucoma

It is an ophthalmic emergency that progresses to blindness if untreated.⠀ ⠀ ⏩It is defined as the appositional or synechial closure of the anterior chamber angle.⠀ ⠀ ⏩The narrowing or closure of the anterior chamber angle blocks the drainage of aqueous humour, resulting in elevated IOP and damage to the optic nerve.⠀ ⠀ ⏩It is caused by FACTORS that either push or pull the iris up into the angle thus blocking the drainage of aqueous humour, raising the IOP and damaging the optic nerve⠀ ⠀ ⏩It arises chiefly through a MECHANISM named pupillary block secondary to mydriasis. ⠀ ✅As the iris dilates and is pulled centripetally and posteriorly causing iris-lens contact, aqueous humour is prevented from passing between the lens and the iris into the anterior chamber. However, aqueous humour continues to be produced by the ciliary body pushing the peripheral iris anteriorly and thus closing the angle. ⠀ ⠀ ✅The RESULTANT EFFECT is to obstruct aqueous outflow and cause a rapid onset of severe intraocular hypertension.⠀ ⠀ ✅A further CAUSE of acute angle closure occurs via the non-pupillary block mechanism, whereby the ciliary body is displaced forward shallowing the peripheral anterior chamber.⠀ ⠀ ⏩It usually presents as a rapid progressive visual impairment in one or both eyes with severe ocular and periocular pain and patients may complain of nausea and vomiting. ⠀ ⠀ ✅The pupil is often fixed and semi-dilated with corneal oedema and ocular redness. On examination, the IOP will be raised (above 21 mmHg) and the optic disc appears cupped.⠀ ⠀ ⏩PREDISPOSING FACTORS include being female, of East Asian descent, having a short axial length (hypermetropia) and a shallow anterior chamber, history of glaucoma, increasing age, thick lens and having a small corneal diameter and a positive family history.