Age-Related Macular Degeneration
Macular degeneration is the commonest reason for blind registration in the western world. There are two forms of the condition, ‘wet’ and ‘dry’. Wet age-related macular degeneration is when new, abnormally located blood vessels grow underneath the retina at the macula causing sudden loss of central vision by leakage of fluid or by haemorrhage. Dry age-related macular degeneration is a slow, progressive deterioration in visual function. Peripheral vision is retained as macular degeneration only affects central vision.
There are several forms of glaucoma. The most common type, primary open angle glaucoma, is characterised by raised intraocular pressure causing damage to the optic nerve and visual field loss. It affects 1% of those aged over 40years and 10% of over 80’s. There is a strong genetic link. Other risk factors include increasing age, diabetes and short sightedness. There are no symptoms caused by primary open angle glaucoma until the disease is advanced, so regular eye examinations are imperative for early detection. This form of glaucoma can be successfully managed using eye drops. Another form, angle closure glaucoma, has an acute onset causing sudden ocular pain, loss of vision, red eye and nausea. This requires urgent treatment and frequently benefits from laser therapy. Glaucoma can also present secondary to other disorders such as uveitis.
Diabetes can affect the visual system directly or indirectly in a number of ways such as eye muscle palsy or cataract, the commonest of which is diabetic retinopathy. It is frequently detected during routine screening before the onset of symptoms. Diabetic retinopathy presents with microaneurysms, haemorrhages, exudates and retinal oedema. Symptoms are usually due to maculopathy or haemorrhaging into the vitreous humour (jelly inside the eye) causing visual loss. Effective control of diabetes can retard both the onset of retinopathy and its progression.
High blood pressure or hypertension can cause retinal problems if it is not sell controlled. Retinal arteries become narrower and nipping can occur at vein/artery crossing points. Microaneurysms, haemorrhages and lipid deposits are other common signs.
This is an inflammatory process affecting the optic nerve. It is a common finding in multiple sclerosis sufferers. Optic neuritis can also be associated with viral infections and other infectious diseases. Mild cases require no treatment, but if vision is severely affected, then medication may speed up recovery.