Age-related macular degeneration
Age-related macular degeneration is the most common cause of severe vision loss in elderly persons. It is a degenerative disease of the central part of the retina — known as the macula — that results in a loss of central vision.
There are two types of age-related macular degeneration, dry and wet. Dry age-related macular degeneration is far more common and considered more favorable. It progresses gradually and may not have a significant effect on visual functions. Wet age-related macular degeneration is usually a more advanced disease state and is associated with rapid distortion and sudden loss of central vision.
Age-related macular degeneration is painless. Symptoms of the disease usually develop gradually and may include:
- Visual distortions, such as straight lines seeming bent
- Reduced central vision in one or both eyes
- Gradual lessening of color perception
- Increased difficulty adapting to low light levels
- Increased blurriness of printed words
- Distorted or blurry vision
- Dimmed vision, especially when reading
- Dark spots in the center of the visual field
If the disease affects only one eye, patient may not notice any changes in vision because his good eye may compensate for the weak eye. Without treatment dry macular degeneration can progress to wet form, resulting in a sudden decrease in central vision.
The condition rarely causes total blindness, because it does not affect peripheral vision.
The causes of age-related macular degeneration involve an interplay of genetic, environmental, metabolic, and functional factors, including aging, family history, smoking, obesity, high blood pressure, and arteriosclerosis.
- Family history of age-related macular degeneration
- Poor diet
- Elevated blood pressure
- Elevated cholesterol levels
To diagnose age-related macular degeneration routine ophthalmic examination is recommended. It includes visual acuity tests, dilated funduscopic examination, optical coherence tomography, fluorescein angiography, indocyanine green angiography, fundus autofluorescence, and ultrasonography. In advanced stages of macular degeneration, referral to a retinal specialist may be required.
As of now, there is no treatment for dry form of age-related macular degeneration. If your condition is diagnosed early, you can take steps to help slow its progression, such as eating healthfully and not smoking. Try to reduce animal proteins and fats and eat more fish, nuts, fruits and vegetables (sweet pepper, carrot, spinach, cucumbers, kiwi, oranges, red grapes). Please avoid widely publicized biologically active food supplements. Only a few of them are clinically proven to be efficient. If there are no changes to retina then no treatment is required.
At the present time, VEGF inhibition, photodynamic therapy (PDT) and laser treatment are considered effective treatments methods.
Based on the angiogenic role of vascular endothelial growth factor (VEGF) in neovascularization, VEGF inhibition has become one of the targets of successful therapies for neovascular age-related macular degeneration. Angiogenesis inhibitors block the abnormal blood vessels and do not allow them to grow, that stimulates a quick recovery of visual acuity and helps retinal edema to dissolve.
Multi-central trails confirmed a high long-term clinical efficiency and safety of using angiogenesis inhibitors and today they are included in national standards of age-related wet macular degeneration treatment in the USA and most European countries.
Anti-VEGF agents are injected directly into the intravitreal cavity so that the procedure is carried out in the operating theatre. In the most cases, patients need injections every four weeks to maintain the beneficial effect of the medication.
Photodynamic therapy is a relatively new method of treatment using a photochemical effect on new blood vessels. A special medication is injected to a patient intravenously then the required part of the eye fundus is affected with a weak laser radiation which is not able to cause any harm to retina. The atomic oxygen is released as the result of the photochemical decomposition of the photosensitizer, this oxygen blocks the abnormal blood vessels and the retinal edema dissolves.
Photodynamic therapy more gently effects the retina and does not cause atrophy of the fundus membranes in comparison with laser photocoagulation.
Recently, photodynamic therapy is gradually replaced by angiogenesis inhibitors, which usually provide higher functional results. With some age-related retinal diseases (polypoidal choroidal vasculopathy) photodynamic therapy is more efficient.
Laser coagulation just after new blood vessels were found outside the macular center can provide a highly functional result.
Laser coagulation of retina inevitably causes a thermal injury to the eye structures. It leads to a tissue dystrophy and locks down possibilities of using laser treatment for age related wet macular degeneration.