GLAUCOMA
glAUcomA g
laucoma 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
Type of Glaucoma chronic open-angle glaucoma (coAg) Acute angle-closure glaucoma (AAcg) Secondary glaucoma childhood glaucoma Normal-tension / low-tension glaucoma Table 1: Types of glaucoma and their causes2,4,5,6 18 - PhARmAcY IN focUS
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
Causes
A partial blockage within the trabecular meshwork restricts the drainage of aqueous humour from eye
Bowing of the iris against the trabecular meshwork blocks the drainage of aqueous humour from eye
caused by another eye problem eg, uveitis, eye trauma, ocular tumour or steroid-induced
Incorrect development of the eyes drainage system before birth
Unknown. Some evidence to suggest vascular dysregulation is a contributing factor
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.
• People of African, Afro-caribbean or Asian descent are at increased risk of developing certain types of glaucoma
• Raised IoP • myopia (short sightedness) • diabetes • female gender • conditions that significantly restrict blood flow to eye e.g. diabetic retinopathy
• Prolonged use of steroids • Eye trauma • Systemic hypertension2
there are several different types of glaucoma. table one outlines the most common types.
WIth ARoUNd tEN PER cENt of UK BlINdNESS AttRIBUtEd to glAUcomA, It IS cRItIcAl thAt PhARmAcIStS hAvE A dEEP UNdERStANdINg of thIS coNdItIoN By timothy mcclure
chRoNIc oPEN ANglE glAUcomA (coAg): this is the most common type of glaucoma accounting for over 70 per cent of cases. As there is a chronic degenerative obstruction that does not allow the aqueous humour to properly drain away from the eye, IoP is increased2
. the condition
usually develops slowly and painlessly over many years, so damage to the optic nerve and loss of sight are gradual. A patient will often not realise they have coAg as the peripheral vision is affected first. Without treatment, vision towards the centre of the eye may also be lost, and patients may present with significant loss of sight4,5
.
In the UK, around one in 50 people aged over 40 have coAg, rising to around one in ten people aged over 75. It is unusual in those aged under 35. If left completely untreated, progression to severe sight impairment typically takes between 25 to 70 years from onset, with those of African descent more likely to become blind2
. With an ageing
population and longer life expectancy, the number of patients with coAg is predicted to rise,
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