Glaucoma describes a range of disorders with a characteristic type of optic disc damage usually due to raised intraocular pressure.
Upper limit of normal intraocular pressure is 21mmHg.
2 main divisions of glaucoma are:
- Open angle = chronic
- Closed angle = acute
Open angle glaucoma
Primary open angle glaucoma occurs in 1-2% of over 40s and over 4% of over 80s
Patients are often asymptomatic – visual losses tend to occur late in the course of the disease and is often peripheral.
Fundoscopy may reveal optic disc cupping
- Major risk factors
- FH in a first degree relative
- Myopia
- Advanced age
- Afro-caribean origin
- Raised intra-occular pressure
- Other risk factors
- Diabetes
- Hypertension
- Hypothyroidism
- Steroid use
- Migraine
- Sleep apnoea
Patients of afro-caribbean origin are at higher risk of progression to blindness
Management
- Medical
- Eye drops
- First line: prostaglandin analogues (increase aqueous outflow from eye through the uveoscleral pathway) or beta blockers (reduce secretion of aqueous)
- Second line: carbonic anhydrase inhibitors and alpha agonists
- Oral medication: carbonic anhydrase inhibitors (reduce secretion of aqueous)
- Surgical
- Argon laser trabeculoplasty
- Trabeculectomy
Closed angle glaucoma
Closed angle glaucoma is a sight-threatening ophthalmic emergency characterized by a rapid rise in intraocular pressure as a result of obstruction of aqueous humour drainage from the anterior chamber of the eye.
Presentation
- Painful red eye
- Semi-dilated, non-reactive pupil
- Periocular headache
- Halos around light
- Loss of vision
- Nausea and vomiting
- Systemically unwell
- Affected eye is tender and feels hard to the touch
Risk factors for closed angle glaucoma include:
- Advanced age
- Female gender
- Far eastern origin
- Hypermetropia
- Medications (due to their pupil-dilating effects)
- SSRIs
- TCA
- Anticholingergics
Treatment
- Acetazolamide IV
- Pilocarpine 4% eye drops
- Laser iridotomy or iridoplasty
- Iridectomy if laser treatment fails
Small print gem: carbonic anhydrase drugs are strucurally similar to sulfonamides so should be avoided if patients have an allergy to these
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