Dry Age Related Macular Degeneration (AMD)
For many people the first they hear about dry AMD is when their optometrist sits back after an eye exam and remarks;
“I’m afraid you have some signs of ageing in the back of your eye.”
Or words to that effect.
At Bettersight we have seen many hundreds of patients suffering from the effects of macular degeneration and many of our patients tell us this kind of tale. Once the words “dry macular degeneration” are released into the conversation it can often leave the patient feeling very anxious and uncertain about the future. In this section we outline the condition of dry AMD. The internet is awash with a lot of information about AMD so what we will do here is focus on answering some of the more common questions that are asked by people who may want to know a little more about this condition.
In this section we outline important facets of this common condition from a patient perspective answering some of the common questions:
What is Dry AMD ?
In its simplest terms dry AMD is the cover all term that eye specialists use to describe the gradual deterioration of some of the cells that help make up the macula. When retinal cells die off they are not regenerated by the body and so over time the effect of this gradual cell loss can accumulate causing some deterioration in eye sight.
In many people the deterioration in the macula is very slow and thankfully the level of sight loss may remain fairly modest. Sadly in some people however, dry AMD can progress more rapidly and can lead to very poor eyesight though it would be unusual for people to experience severe loss of eyesight purely due to dry AMD.
The condition is called dry to differentiate it from its associated condition called wet AMD. Dry AMD does not in any way refer to how dry your eyes are - contrary to popular opinion! In fact the term dry simply refers to the absence of abnormal blood vessels under the macula that often lead to swelling & bruising of the retina, bleeding and exuberant scar formation.
In dry AMD there are several different type of changes that occur in the ageing macula. Its important to be ware that for the over 75 age group some level of dry ageing changes in the macula are fairly common with perhaps upto 10-15% of people in this age range showing some minor signs of age related macular degeneration. A comprehensive outline of dry AMD is outside the scope of this website but the major physical changes in the macula are as follows:
- DRUSEN . These are tiny yellow - grey coloured deposits that form under the retina and impair retinal photoreceptor cell function. These deposits develop quite slowly, often over many years and can grow in size and are a classic hallmark of dry AMD.
- ATROPHY. This terms refers to the gradual wearing away of some of the cells that line the undersruface of the retina. If you imagine the retina to be like the carpet on your floor, then a single layer of cells called the retinal pigment epithelium (RPE) would correspond to the underlay behind the carpet. The RPE is an extremely important part of the retina and is integral to the function of the retinal photoreceptors that sit right on top of it. Any loss of RPE cells will lead to damage and ultimately loss of the overlying photoreceptor cells. RPE atrophy is often associated with DRUSEN formation but can occsaionally be quite isolated. If the area of RPE atrophy affects the very central part of the macula then eyesight can be very severely affected.
- PIGMENT CLUMPS. As part of the wear and tear process of dry AMD and for reasons that are not clear, some of the RPE cells described above can degenerate and leave clumps of dark pigment granules in the macula. This type of dry AMD change is perhaps more commonly associated with a progression towards wet AMD (see next section).
- PED. Pigment epithelial Detachment. This refers to a build up of fluid under the RPE cells that can occur in dry AMD but is also strongly linked to wet AMD. In such cases expert attention is required to accurately differntiate between dry and wet forms of AMD.
Whats the Prognosis for dry AMD ?
The outlook for dry AMD will vary considerably between person to person and even eye to eye within each person. The likelihood is that for most people dry AMD will tend to progress fairly slowly -often over many years.
The rate of progression will depend largely on the extent and severity of dry AMD when it first comes to light in a medical consultation. In the renowned AREDS I trial the overall rate of progression of dry AMD when in its earliest stages was only around a 1% risk over a five year time frame. However for people with much more established dry AMD it was found that the natural progression rate towards what is termed 'advanced AMD' was closer to 30% over the same five year time frame.
The good news however is that the chance of experiencing very poor eyesight is still very low with pure dry AMD. Many people are terrified of the prospect of blindness from dry AMD - it is reassuring to know that true blindness - often called black blindness should NOT occur with dry AMD even in its most severe form. Sadly however in a tiny fraction of people with dry AMD it is still possible to experience severe eyesight loss over many years.
Please read on to discover treatment options and ways to manage poor eyesight resulting from dry AMD.
Can dry AMD turn into wet AMD ?
The simple answer is unfortunately YES it can.
Once again the chance of progression to wet AMD from a starting diagnosis of dry AMD varies from eye to eye and from person to person. For people with early stage dry AMD the risk of conversion to wet AMD is fairly low - around 1-2% over a five year time frame.
For people with more severe dry AMD to start with the risk of this conversion to wet AMD is much higher and may in the most severe cases may amount upto a 10% risk per year. If a patient has already developed wet AMD in one eye then sadly the other eye is more likely again to develop wet AMD at some point in the future.
This is why at Bettersight we encourage our patients to self monitor their eyesight and to report any changes in eyesight without undue delay.
Symptoms to watch out for are:
- A general deterioration in eyesight - especially reading vision
- A change in the area and type of distortion - often best seen by monitoring on a square grid chart - probably best done at least once a week with each eye separately and with reading sepcs on
- Other symptoms such as flickering vision disturbance are probably best reported.
If any such symptoms occur after a starting diagnosis of dry AMD we advise urgent specialist review wherever possible.
What are the treatment options ?
At the present time there is no recognised formal treatment for dry AMD. However ! There are various measures that the patient can take that may help to slow down the rate of progression of dry AMD. At Bettersight we advise the following:
- Meet with your GP and try and optimise your general health -especially blood pressure and cholesterol levels
- If you are a smoker - then please do your best to quit - your GP can help on this front too
- Consider a consultation to determine whether you would benefit from taking vitamin supplementation with the AREDS formulation - containing
- 500 milligrams of Vitamin C
- 400 international units of vitamin E
- 15 milligrams of beta-carotene (sometimes labelled as 25,000 international units of vitamin A)
- 80 milligrams of zinc as zinc oxide
- 2 milligrams of copper as cupric oxide
- The AREDS formulation is widely available in various brand names such as viteyes AREDS formula or ocuvite preservision amongst others - its often taken as one tablet twice daily with meals. The copper is added only to help prevent copper deficiency anaemia which can occur when high doses of zinc are taken.
- IOl-VIP lens implant treatment
- IMT - miniature telescopic lens implant device
When should I seek a Consultation ?
At Bettersight we recommend you seek advice for dry AMD in the following circumstances:
- If you've been given a diagnosis of AMD by your optometrist and wish to know more about your condition to help optimise your management.
- If you've seen a hospital specialist but feel you werent given enough time to air your concerns.
- If you've had some alteration in your eyesight and you're concerned about the condition progressing or turning into wet AMD.
- If you have very poor eyesight and you wish to explore the possiblities of surgical management with advanced magnifying lens implant devices such as IOL-VIP or the IMT device that was recently approved for use in the U.S.A by the FDA.
Where can I find out more ?
In order to help further your research of this condition that we know causes much anxiety we have collated a few external links for you to visit.