What Is Macular Degeneration?
Macular degeneration (AMD) is the leading cause of vision loss and blindness in Australia. It blurs the sharp, central, fine detail vision that you need for “straight-ahead” viewing. AMD affects the macula, the central area of the retina at the back of your eye that allows us to see fine details. AMD mainly affects older people: 4%>40yrs, 9%>50yrs, 23%>65yrs, 31%>80 yrs have some form of AMD. The most common symptom is blurred vision. In the wet form an early sign is that straight lines appear wavy.
What Causes It?
The causes are till not fully understood, however a lifetime of exposure to UV light, production of free radicals and reduced blood flow to the retina may result in abnormal changes in the thin pigmented layer called the retinal pigment epithelium (RPE) There are two categories of AMD:
- DRY: In the early stages there is an accumulation of yellowish deposits called drusen, as well as a loss of pigment cells in the RPE. This may progress with greater areas of pigment degeneration and scarring. This will result in greater blur in the central vision. 90% of AMD is the dry form.
- WET: This occurs when abnormal blood vessels under the retina start to grow up through the retina and the breaks in the pigment layer. These new blood vessels are weak and porous and tend to leak and bleed quite easily. This can result in fluid build up and swelling, as well as bleeding (hence WET). In this case damage to the macula and loss of vision can be very rapid. If not treated promptly, the fluid can leave significant scars which result in permanent severe loss of central vision.
The are several risk factors for AMD including:
- >50 yrs
- Smoking; you are almost three times more likely to develop AMD if you smoke
- Being overweight
- The risk is greater with a family history
- Cardiovascular disease or hypertension
- A history of significant exposure to UV, e.g. always worked outdoors
- Women are at a greater risk than men