With around ten per cent of UK blindness attributed to glaucoma, it is critical that pharmacists have a deep understanding of this condition.
An insight into glaucoma
By Timothy McClure
Glaucoma is one of the most common eye conditions encountered in primary care. It is a disease of the optic nerve including characteristic damage to the optic nerve head and typical defects in the visual field, with or without increased intraocular pressure (IOP)1. This generally leads to a progressive loss of sight affecting one or both eyes, though it often progresses more quickly in one eye than in the other2. Glaucoma is a leading cause of blindness with approximately ten per cent of UK blindness registrations attributed to the disease and on a global scale, it is the second leading cause of blindness after cataracts1,3. Therefore it is critical that we as pharmacists should have a deep understanding of this condition, how it presents and the medication used to treat it.
Risk factors associated with glaucoma include:
- Positive family history – incidence increases two to four fold if have an affected sibling
- Age – glaucoma becomes more likely as get older, with most people aged over 75 at diagnosis
- People of African, Afro-Caribbean or Asian descent are at increased risk of developing certain types of glaucoma
- Raised IOP
- Myopia (short sightedness)
- Female gender
- Conditions that significantly restrict blood flow to eye eg, diabetic retinopathy
- Prolonged use of steroids
- Eye trauma
- Systemic hypertension2
There are several different types of glaucoma. Table one outlines the most common types.
|Type of Glaucoma||Causes|
|Chronic open-angle glaucoma (COAG)||A partial blockage within the trabecular meshwork restricts the drainage of aqueous humour from eye|
|Acute angle-closure glaucoma|
|Bowing of the iris against the trabecular meshwork blocks the drainage of aqueous humour from eye|
|Secondary glaucoma||Caused by another eye problem eg, uveitis, eye trauma, ocular tumour or steroid-induced|
|Childhood glaucoma||Incorrect development of the eyes drainage system before birth|
|Normal-tension / low-tension glaucoma||Unknown. Some evidence to suggest vascular dysregulation is a contributing factor|
|Table 1: Types of glaucoma and their causes2,4,5,6|