Glaucoma (Part three)

Angle-closure glaucoma

• sudden eye pain
• red eye
• seeing halos around lights
• increased intraocular pressure
• nausea, vomiting
• sudden decrease in vision
• pupil is fixed and moderately dilated

Diagnosis

Screening for glaucoma is part of the standard ophthalmologic examination performed by ophthalmologists and optometrists. A glaucoma test should include measuring intraocular pressure through tonometry, examination of the anterior chamber angle (gonioscopy), and examination of the optic nerve.

Treatment

Intraocular pressure can be reduced with medications in the form of eye drops. Different classes of drugs are used to treat glaucoma, each of which can have local and systemic effects:

• prostaglandin analogs, which increase the outflow of eye fluid through the iridocorneal angle
• beta-adrenergic receptor antagonists, reduce the production of eye fluid by the ciliary body
• alpha2 adrenergic receptor agonists, reduce the production of eye fluid and increase its outflow through the angle between the cornea and iris
• miotic agents, cause contraction of the ciliary muscles and opening of the trabecular meshwork allowing the outflow of eye fluid through the iridocorneal angle
• carbonic anhydrase inhibitors, reduce the secretion of eye fluid by inhibiting carbonic anhydrase in the ciliary body.

Surgical Treatment

Both conventional and laser surgery are used in the treatment of glaucoma.

Through laser surgery in open-angle glaucoma, either the outflow of eye fluid is increased or the blockage of fluid circulation is eliminated in angle-closure glaucoma.

Types of laser surgery in glaucoma include:

• trabeculoplasty where the laser is used to open the trabecular meshwork in the drainage space
• iridotomy where a small hole is made in the iris allowing a freer circulation of fluid
• cyclophotocoagulation through which the production of eye fluid is reduced.

Trabeculectomy

In this operation, a new channel is created for the drainage of eye fluid thereby reducing intraocular pressure.