Chronic Closed Angle Glaucoma

Excerpt

Glaucoma is a progressive optic neuropathy generally associated with elevated intraocular pressures, leading to visual field loss. In its advanced stage, it has the potential to culminate in total blindness. Angle-closure glaucoma occurs due to the narrowing or closure of the anterior chamber angle, typically responsible for facilitating the drainage of aqueous humor.

Acute angle-closure glaucoma is a condition that occurs when there is a gradual narrowing of the anterior chamber angle, which obstructs the drainage of aqueous humor, leading to elevated intraocular pressure and subsequently damaging the optic nerve. Chronic angle-closure glaucoma occurs when a portion of the angle is intermittently obstructed, resulting in subsequent scarring and narrowing of the angle further over time. Characteristic features of chronic angle-closure glaucoma include the gradual formation of peripheral anterior synechiae (PAS) and irreversible iridotrabecular adhesions, which impede aqueous outflow, leading to elevated intraocular pressures. In all forms of angle-closure glaucoma, iridotrabecular contact occurs, wherein the iris is observed to make contact with the anterior chamber angle, either at the posterior pigmented trabecular meshwork or more anterior structures.

Angle-closure glaucoma can be classified as either primary or secondary. Primary angle-closure (PAC) glaucoma is attributed to a physiological predisposition and is not associated with any other ocular condition or eye disease. In contrast, secondary angle-closure glaucoma is associated with one or more additional ocular conditions. In PAC, the lens is positioned too far forward, pressing against the iris and causing the peripheral iris to bulge due to increased pressure in the posterior chamber. Certain factors such as iris neovascularization, trauma, and uveitis can push the iris or ciliary body forward or deform the iris, leading to its retraction into the angle and resulting in secondary angle-closure glaucoma. Individuals with PAC glaucoma are predisposed to this condition, whereas those with secondary angle-closure glaucoma have an underlying condition that contributes to the narrowing of the anterior angle.

Acute angle-closure glaucoma is characterized by decreased visual acuity, headache, severe eye pain, nausea and vomiting, and halos around lights. This condition is considered a medical emergency and requires swift treatment to prevent permanent vision loss. Chronic angle-closure glaucoma can manifest with or without symptoms and may later cause potential damage to the optic nerve. Intraocular pressure gradually increases with chronic angle-closure glaucoma, leading to the designation of "silent" angle-closure glaucoma. This condition primarily involves iridotrabecular contact, resulting in synechiae formation and subsequent angle closure, and it is also referred to as "creeping" angle-closure glaucoma.