EYE HEALTH
to uncover why some optic nerves are damaged by relatively low eye pressures. Interestingly, people with a history of systemic heart disease such as an irregular rhythm have been found to be of greater risk. This suggests vascular dysregulation could be a contributing factor6,9
.
OCULAR HYPERTENSION: Some patients have increased IOP with no damage to the optic nerve or loss of vision. Raised eye pressure without signs of glaucoma is called ocular hypertension. This condition increases a person’s risk of developing glaucoma. Around one in ten of those with untreated ocular hypertension will go on to develop glaucoma. As a result, some people with ocular hypertension will receive treatment based on their estimated risk of developing COAG1,9
.
TREATMENT Eye drops are the main stay of treatment for glaucoma4
. Treatment
with a prostaglandin analogue is recommended for those patients with early or moderate COAG (the most common type of glaucoma seen in community practice)1
. The most
common prostaglandin analogues include Latanoprost, Tafluprost and Travoprost. These drugs reduce IOP by increasing the eyes outflow of aqueous humour4
.
If IOP has not been reduced sufficiently to prevent the risk of progression of vision loss, alternative treatment can be offered. More than one agent may be used concurrently to achieve optimal IOP1
.
Beta-blockers reduce the rate of production of aqueous humour. Examples include Betazolol and Timolol. Oral administration results in too many side effects and so eye drop formulations are used1,4
.
Carbonic anhydrase inhibitors such as Brinzolamide and Dorzolamide eye drops decrease IOP by reducing aqueous humour production, but are generally used in patients resistant to beta-blockers or in those for whom beta-blockers are contra-indicated.
REFERENCES
1. NICE Clinical Guideline 85 Glaucoma: diagnosis and management
https://www.nice.org.uk/guidance/cg85 [Online] 2. Patient: Glaucoma and ocular hypertension
http://patient.info/doctor/glaucoma-and-ocular-hypertension [Online] 3. Quigley, Br J Ophthalmol. The number of people with glaucoma worldwide in 2010 and 2020
http://bjo.bmj.com/content/90/3/262.short [Online] 4. British National Formulary Issue 72 5. NHS Choices Glaucoma
http://www.nhs.uk/conditions/Glaucoma [Online] 6. Glaucoma Research Foundation. Normal-tension glaucoma
http://www.glaucoma.org/glaucoma/normal-tension-glaucoma.php [Online] 7. Medscape. Drug-induced glaucoma
http://www.emedicine.medscape.com/article/1205298-overview [Online] 8. Glaucoma Research Foundation. Childhood glaucoma
http://www.glaucoma.org/glaucoma/childhood-glaucoma-1.php [Online] 9. Patient: Chronic open-angle glaucoma
http://patient.info/health/chronic-open-angle-glaucoma glaucoma [Online]
34 - SCOTTISH PHARMACIST
Acetazolamide is a systemic carbonic anhydrase inhibitor given orally or via injection. It is used as an adjunct and should not be given long term1,4
.
Sympathomimetics, such as the selective alpha2-adrenoceptor agonist Brimonidine, are also an option in COAG treatment when other agents are either inappropriate or have failed to control IOP alone1,4
.
Combination eye drops are also available to reduce IOP when single agents alone are not adequate4
before alternative therapy is commenced as many patients do not use these eye drops correctly and so receive sub-optimal therapy. Table two outlines the key advice to give to patients instilling eye drops.
. These
products combine the beta-blocker Timolol with either a prostaglandin analogue or a carbonic anhydrase inhibitor. Examples include Latanoprost + Timolol and Brinazolamide + Timolol. Patient adherence can be improved as these products reduce the amount of drops a patient must instil.
It is vital to check patient adherence and eye drop instillation technique
If eye drops alone do not lower IOP sufficiently, laser treatment may be offered. Also called laser trabeculoplasty, small holes will be created in the trabecular meshwork to improve aqueous humour drainage. Eye drops may still be needed after this treatment. Surgery is also an option. A trabeculectomy creates a channel for the aqueous humour to bypass the trabecular meshwork1
.
The outlook for glaucoma varies depending on which type a patient is diagnosed with, but generally it will result in some degree of permanent vision loss. It may affect the ability to carry out certain tasks, but most retain useful vision for life. Only a
small proportion of people glaucoma cases result in blindness5
. It is useful to
remember that patients who drive and have glaucoma causing loss of vision in both eyes must, by law, inform the Driver and Vehicle Licensing Agency (DVLA)9
.
The long-term outcome of glaucoma is better with earlier diagnosis and treatment. Glaucoma can usually be detected during a routine eye test at an opticians. This eye check can detect the early signs of glaucoma before significant vision loss has occurred. As pharmacists, we should encourage patients to have routine tests at least every two years, especially those aged over 50. These eye tests will include measurements of the intra-ocular pressure and tests of peripheral vision and are especially important for those with associated risk factors as listed at the start of this article5
. •
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