What Is Macular Degeneration?
Macular degeneration (MD) or age related macular degeneration (AMD or ARMD) also previously known as senile macular degeneration, is one of many “eye problems” I have encountered during my time as a consultant ophthalmic surgeon. This medical condition results in a loss of vision in the centre of the visual field (the macula) because of damage to the retina.
Macular degeneration can make it difficult or impossible to read or recognise faces, although enough peripheral vision can remain to allow other daily life activities.
Dry Macular Degeneration and Wet Macular Degeneration
There are two forms of macular degeneration; these are “dry macular degeneration” and “wet macular degeneration“. By far the more common type is the dry type accounting for 85-90 percent of cases with the wet type accounting for the remainder.
The “dry” form of advanced MD begins with yellow deposits between the retinal pigment epithelial layer and the choroid (the vascular layer of the eye, containing connective tissue, and lying between the retina and the sclera). These deposits can build up between these two layers which causes vision loss through loss of photoreceptors (rods and cones) in the central part of the eye.
The “wet” form of advanced MD causes vision loss due to abnormal blood vessel growth. These blood vessels can bleed because they are fragile and can leak. The bleeding can eventually cause irreversible damage to the photoreceptors which can result in sudden and dramatic loss of vision if left untreated.
Who It Affects
AMD is a major cause of blindness and visual impairment in older adults. However as with most chronic degenerative diseases, macular degeneration now often has its onset at a relatively young age. It is possible to recognise early changes in the retina which herald future macular degeneration and opticians are adept at detecting these signs during routine sight testing.
The probable reason for the earlier onset of the disease is that we are subjected to far more environmental toxins than we were previously as well as the diminished quality of our nutrition.
Individuals with an increased risk of developing macular degeneration are those with a family history of the condition, or who have been smokers or who have an unhealthy diet. However, macular degeneration can develop even when none of these risk factors exist.
Macular Degeneration Symptoms
The earliest symptom is an awareness of distortion of central vision, straight lines appear to be bent, a circular object such as a cup appears to be oval; when reading, letters or words are missing or the centre of an object appears blurred, e.g. a face or a clock.
Your doctor may ask you to look at an Amsler grid. An Amsler grid is made up of horizontal and vertical lines used to monitor a person’s central visual field. Patients with macular disease may see wavy lines or some lines may be missing. It is very important to report any irregularity to your eye doctor immediately!
Normal Amsler Grid
Wavy or Missing Lines
Download an Amsler grid for personal use.
Other tests may include measurement of your visual acuity and a dilated exam of the retina.
Macular Degeneration Treatment
There is a treatment for wet macular degeneration which can be successful at preventing further loss of sight. However unless the disease is caught early irreversible damage often occurs. The treatment involves injections of anti-vascular endothelial growth factor into the eye to reverse abnormal blood vessel formation. This is very expensive and with an ageing population the health service will struggle to meet the increasing cost of more people needing treatment.
For dry AMD it is believed that with age the amount of lutein, a pigment in the macula is reduced. Taking extra lutein especially high dose synthetic lutein, may not help as the lutein-binding protein in the macula becomes saturated and the extra lutein will not be taken up. It may be more logical to obtain the lutein required by the macula from natural sources, such as kale, spinach or broccoli.
The ideal scenario would be to prevent rather than to treat macular degeneration. There is evidence that a good plant-based diet high in vitamins A (beta-carotene), C, and E – as well as lutein and zeaxanthin – which provides good quality natural antioxidants, will be beneficial in this prevention and may slow the progression of dry AMD and reduce your risk of getting wet AMD in selected cases.
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- NHS Choices – Macular degeneration: http://www.nhs.uk/Conditions/Macular-degeneration/Pages/Introduction.aspx
- Medline Plus (video): http://www.nlm.nih.gov/medlineplus/ency/anatomyvideos/000085.htm