Pharmacists cannot stop the progressive loss in central vision that comes with age-related macular degeneration, but they can help patients understand the treatment options.
Age-related macular degeneration (AMD) is a chronic disease leading to progressive central vision loss. The symptom of central vision loss is due to the fact that the damaged macula is in the centre of the retina. Patients with AMD may be unable to recognise faces, read, or drive a vehicle.
AMD is the most common cause of sight loss in people over the age of 50 in Ireland and it’s estimated that 7% of Irish people over 50 years of age are living with AMD. On account of our ageing population, the number of people in Ireland affected by this condition is expected to increase.
Symptoms of AMD include decreased central vision, central scotoma, and metamorphopsia.
Scotoma is an area of partially diminished vision surrounded by a field of normal or well-preserved vision. Metamorphopsia is a visual defect that causes people to see objects in a distorted manner; straight objects appear wavy or curvy. Patients will complain of distorted vision, lack of bright colours, or blurred vision.
There are 2 types of macular degeneration: dry and wet. All AMD begins as “dry.” In some cases, it progresses to “wet,” which is a more severe form characterised by abnormal blood vessel growth that produces fluid in the retina. Wet age-related macular degeneration (wet AMD) is the leading cause of severe vision loss and legal blindness in people over the age of 65 in North America, Europe, Australia and Asia.
Dry macular degeneration, also known as the nonexudative form, is more common and found in approximately 90% of AMD patients. The onset of dry AMD is subacute. Management of dry AMD includes attempts to prevent progression to and frequent monitoring for the development of wet macular degeneration.
Wet (also known as exudative or neovascular) macular degeneration occurs in about 10% of AMD patients. It is the more acute form and more likely to cause vision loss.
Wet AMD (age-related macular degeneration) is a chronic, degenerative condition characterised by abnormal blood vessels that grow underneath the retina. The condition gets worse as these faulty blood vessels leak fluid in the back of the eye. This may lead to swelling and damage of the macula, the part of the retina that lets you see colour and maintain sharp vision.
A healthy retina is a dry retina. If this fluid isn’t controlled, central vision will gradually get worse, leading to difficulty doing everyday activities such as reading, recognising faces and driving.
The leaky blood vessels are caused by an excess of a tiny protein called vascular endothelial growth factor (VEGF). Most eye doctors agree that the best way to control these tiny proteins is with an anti-VEGF treatment. Treatments that help control fluid and stop blood vessels from leaking may slow the progression of wet macular degeneration. What are the symptoms?
• Gaps or dark spots (like a smudge on glasses) may appear in their vision, especially first thing in the morning. Objects in front of them might change shape, size or colour or seem to move or disappear.
• Colours can fade.
• Sufferers may find bright light glaring and uncomfortable or find it difficult to adapt when moving from dark to light environments.
• Words might disappear when they are reading.
• Straight lines such as door frames and lampposts may appear distorted or bent.
In Dry AMD symptoms are often mild, such as needing stronger glasses or better lighting for reading. When progression to Wet AMD occurs, the patient may notice the onset of blurring of reading vision with distortion (due to fluid or blood under the macula). Sometimes patients are unaware until they take a moment to cover or close one eye at a time. At this stage, the progression can be rapid and patients should seek help promptly from their eye doctor.
Amsler Grid
An Amsler Grid is a simple test designed to pick up symptoms of Wet AMD. However, it is not a substitute for an eye examination. The patient checks each eye separately with reading glasses on. If they notice new blurring or distortion of the lines on the grid this could indicate the presence of Wet AMD and they should be examined promptly by their eye doctor.
Causes
The exact cause of AMD is unknown. However, extensive research efforts over the last decade are playing an important role in uncovering some of the clues as to what may be causing the disease.
Researchers know that certain genes can cause AMD, but they don’t know what triggers the gene. While AMD can be inherited, many lifestyle choices can make progression of the disease worse.
Some risk factors that are believed to increase the chances of developing AMD include being over the age of 50 and having a family history of AMD. Having high blood pressure, a poor diet or being overweight are also thought to be risk factors for this condition.
Because the exact causes of AMD are not yet known, some people may develop AMD even in the absence of these risk factors.
Age-Related Studies (AREDS1 and AREDS2) have shown that a combination of vitamins and antioxidants may help reduce the risk of progression of Early AMD to late-stage AMD. The recommendations include supplements containing vitamins C and E, zinc, copper, lutein and zeaxanthin.
Treatment for Wet AMD is most often through a series of injections into the eye using a drug called anti-VEGF (anti-vascular endothelial growth factor). This treatment works by reducing the growth of new blood vessels. Response to this treatment is usually better in the early stages of Wet AMD, although even later stages can be stabilised. In some cases, individuals may notice improvements in their vision. It is important to remind patients at risk for AMD to have regular eye exams, even when they are symptom-free. Patients complaining of a recent or chronic loss or change of vision should be urged to see an ophthalmologist immediately. A healthy lifestyle may help prevent AMD. This includes not smoking, eating a healthy diet, and being physically active. Following the recommended guidelines and the use of appropriate pharmacologic agents may help patients with AMD slow vision loss progression, increase visual acuity, and experience a greater quality of life.
Knowing the symptoms and signs to be aware of:
1. Symptoms: look out for straight lines appearing wavy.
or distorted, e.g. a doorframe. If you see a smudge, gaps or dark spots appearing in your field of vision, or have difficulties in reading small print, even with glasses, or difficulty in recognising faces, it is recommended to make an appointment with an eye doctor, optometrist or GP as soon as possible.
2. Risk groups: People over 50 should have a regular eye exam (every 2 years or as directed by the doctor). If you have fair skin, light eyes, high blood pressure, or have been exposed to prolonged periods of sunlight, then you should also have regular check-ups.
3. Healthy diet: eat a diet low in saturated fats and rich in omega 3 fatty acids (oily fish and walnuts). Green, leafy vegetables (spinach and kale) contain antioxidants, eggs and yellow/orange-based fruit contain nutrients such as lutein, zeaxanthin and beta-carotene –all work to protect the macula.
4. Vitamin supplements: certain nutritional supplements containing vitamins C and E, zinc, copper, lutein and zeaxanthin can slow down.
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