The two types of ARMD
Dry ARMD occurs when the layer called the retinal pigment epithelium - the layer that rids the retina of waste products and transports nourishment and oxygen to the retina - does not function properly. For the 13.000 people diagnosed each year by dry ARMD, the disease usually takes a very slow course.
Wet ARMD is often found in conjunction with the eye’s attempt to repair for dry ARMD, or the development of new retinal blood vessels. It is these newly formed blood vessels that can cause distortion of the sight. Retinal blood vessels may rupture and leak blood and fluid into the retina. Consequences often exhibited by this form of ARMD are rapid reduction of sight and the ability to read, image distortion, and /or loss of colour sight. The patient can simply have a difficult time recognizing friends when they meet them in the street.
ARMD patients experience the gradual loss of central vision. Central vision is essential for focusing on details, for watching television, our ability to recognize others, for reading or driving a car.
Most ARMD patients keep their orientation vision and can still go about on their own and manage in their homes. They can visualize along the periphery, but when focusing on an object it can disappear or become blurred.
The research community does not have a treatment for Dry ARMD available. There are however a few treatment techniques available for wet ARMD if the patient gets immediate treatment. At best the disease can be stopped, not cured, and eyesight can be permanently impaired.
Today, there are two new methods of treatment for Wet ARMD.
Some communities in Japan did not develop macular degeneration as people aged, but as soon as they started eating Western food the condition started to occur. Similarly, when Japanese people move to Western countries, they develop the condition more frequently.
These observations suggest that the high fat (and type of fats, such as saturated and trans-fats) in our diet, the lack of protective fats (omega 3s, from fish), and salt (by increasing blood pressure) increases the number of people with ARMD.
We inherit these from our parents. Genes are the genetic information that tells our body what chemicals to make. Overall, our genes may contribute to more than 50% of ARMD. The genes that may cause macular degeneration probably control the way used-up chemicals are removed from the eye.
Being long-sighted (hyperopic) is also a risk factor.
|A healthy lifestyle helps to prevent age related macular degeneration. This is important for the younger relations of age related macular degeneration sufferers: || |
- Overall smoking accounts for 32% of ARMD. Even stopping at the age of 80 will reduce the risk of developing the disease.
So if you have a relation with macular degeneration, try and stop as smoking may make it develop earlier.
- Smoking increases the risk of macular degeneration about 3 times. Macular degeneration occurs 10 years earlier in smokers.
- If you have macular degeneration, do try and stop. Even if you are 90 years old stopping smoking will help your eyes considerably.
- Passive smoking is also harmful: for instance, if your partner smokes cigarettes a day, you body receives 25% of the smoke, so that is equivalent to you smoking 5 cigarettes a day.
- Each cigarette increases the progression rate of ARMD ~15%
Blood Pressure & Exercise
- 30 minutes a day at least, walking, or more active exercise for younger people, reduces risk by 70%. Exercise may help by preventing hardening of the arteries.
30 minutes walking a day for example...regular walking, for example, three times a week will result in less than a third of the amount of neovascular ARMD compared to people who don't walk or exercise and who drive everywhere.
- A low blood pressure helps. A level of 140/85 or below is likely to be best. Blood pressure is written as '140/85', with the systolic/diastolic. Above 115 (systolic) the risk of heart disease increases. Macular haemorrhages are more likely with high blood pressure.
Obesity is also a risk factor
- A low salt diet is important Salt and more than 2 units of alcohol a day may cause blood pressure to rise.
Too much may contribute indirectly by increasing blood pressure, and is related to ARMD, May be red wine (in small amounts) is healthier.
Blood pressure rises after drinking (opposite...drinking 4 pints/bottle of wine).
Each gram of alcohol puts systolic blood pressure up 0.24mmmHg, diastolic 0.16 mmHg. This means 1 pint of beer (2 units, each unit 8g alcohol) with 16gm of alcohol, if drunk every day, will put the systolic blood pressure up (16 x 0.25=) 4mmHg.
Experts recommend a healthy diet.
- This should include a variety of vegetables and fruit
(at least 5-9 x 100gm portions/day),
- low fat only dairy food
- the minimum of trans and saturated fat
- the minimum of red meat, as part of a balanced diet
- oily fish ...2 small portions a week
- 1-2 hours exercise a day
- A low salt diet is important
- Vitamin D reduces risk, as in milk
- a Mediterranean or Japanese diet (as was 20years ago) is likely to protect.
Fruit/vegetables prevent 36-50% of ARMD (fruit & vegetables lower homocysteine levels, and this improves blood flow).
Pulses like beans are fine. Bread, pasta, rice and potatoes provide ‘energy’.
Vegetarians have lower blood pressures and healthier lipid levels. A healthy diet reduces homocysteine levels, which are associated with ARMD.
Certainly saturated fats increase the risk of ARMD; and fish and polyunsaturated fats halve the risk. Avoiding certain fats helps, with strong evidence. Nuts may help prevent ARMD (small amounts).
5-9 portions of fruit/vegetables a day, with portions of different colours
5 is a minimum..best 9 for men, 7 women, 5 children.
If you are unable to eat this many vegetables, low dose multivitamin tablets may help, but too many vitamins may be harmful. Lack of vitamins has been linked to macular degeneration
Some research suggests that the pigments in vegetables might be helpful, as these are the pigments found in the healthy macula.
Lutein is in most fruits and vegetables, one type of zeaxanthine is in corn, nectarines and oranges (and other yellow/orange fruits/vegetable), but one type is not normally present in the diet. However, some supplements include doses that are too high, so once again, these are probably best as part of a healthy diet.
Zinc may be helpful, but only in low dose, and is probably best as part of a healthy diet.
Beta-carotene supplements are not recommended for smokers, as they may contribute to lung cancer. A review (2006, Drug and Therapeutics Bulletin) recommmeded a healthy diet including green vegetables diet was preferable to supplements.
The AREDS vitamins reduce ARMD by 25% if diet is not discussed. It is not known whether or not they help patients who have a healthy diet.
Ocuvite-Lutein has the most logical formulation...but a healthy diet may be better still.
|Oily fish twice a week reduces ARMD by 40% especially oily fish such as tuna, mackerel, sardines, herring, and salmon. A Japanese diet may be helpful as above. Other omega 3 fats are helpful. |
ARMD is commoner in people with higher cholesterol levels. Atherosclerosis, caused by a high cholesterol, does contribute to ARMD,
Statin treatment reduces macular degeneration. Although statin tablets are not yet formally recommended by all agencies, this author would recommend them for people with ARMD.
Naturally all relatives of ARMD patients should address this issue of fat levels in the blood, sticking to a low fat diet with plenty of exercise, avoiding obesity, just as described on this page for ARMD patients.
Cataract surgery leads to an extra 4-5 times risk of developing neovascular macular changes or dry ARMD (this is controversial). Certainly patients with early ARMD undergoing cataract surgery should be warned of symptoms, that is distortion or changes in central vision, and attention should be sought in a few days.
Age-related macular degeneration (ARMD) is usually a progressive condition.
Dry ARMD progresses over many years. Sight does deteriorate, but most people manage to cope well, although reading is difficult and life may be different. In sime types of dry ARMD progression may be very slow, but it may be quicker in other types.
Dry ARMD may progress to the 'wet type', but this is not always the case.
Wet ARMD begins as new vessels growth in the macular area, causing retinal leakage and swelling. It progresses to cause a scar in the macular area. If the scar is small, sight is reasonable; if large, the sight can be very poor.
Imagine your retina has five layers. Normally this retinal appearance stays constant even in old age, but changes may develop as you get older.
As we get older, changes develop in the retina. The bruchs membrane thickens and the choroidal blood vessels change.
The thickened bruchs membrane prevents waste products leaving the retina and also prevents nutrients entering. This is thought to be a direct cause of the condition. Lipofuscin (type of fat) accumulates in the retinal pigment epithelium; this damages the pigment cells which eventually die.
The choroidal circulation changes...the blood vessels become larger but fewer. This is probably mainly due to a 'hardening of the arteries' that happens elsewhere in the body, particularly with a Western diet.
The invisible changes progress to cause dry ARMD,
- patches of extra thin retina develop, just as though the retina is 'worn out . Often the patches of thin retina gradually get larger, reducing sight.
- Deposits of waste products may develop, called drusen
- pigment changes develop
- the dry changes may convert to 'wet ARMD'
- difficult seeing in dim light
- difficult seeing in bright light
- slow recovery in bright light
- poor central vision when you wake up
If you notice these problems then you are probably at risk and need a check from an optometrist or ophthalmologist. If there are no visible changes, the author would strongly recommend a healthy lifestyle as prevention...it helps your general health in any respect. (This section: after Prof. Bird)