No effective treatment is available for dry AMD. There is an increasing vogue for administering
Figure 19.3. Wet macular degeneration: a Fundus photograph: early disease. b Fundus photograph: advanced disease. c Fluorescein angiogram: early disease.CQ
c vitamins A, C and E, selenium, copper, zinc, zeaxanthin, carotenoids and lutein preparations to patients. These have been shown to protect against progression of dry AMD to more advanced stages of the disease in high-risk patients. They are thought to reduce the damaging effects of light on the retina through their reducing and free-radical scavenging actions.
Some types/stages of wet AMD are treatable. Currently, there are two clinically proven treatments for wet AMD, although the treatment for some eyes is still unsatisfactory.
Controlled trials of the effect of laser photocoagulation of the choroidal new vessels have shown that this treatment is useful in extrafoveal CNV (i.e., when the leakage is not directly under the fovea). Laser photocoagulation ablates the CNV. It is important that those cases that are likely to benefit from treatment are first identified quickly. At the present time, this entails photography of the fundus and fluorescein angiography, and infrared angiography with indocyanine green. Often patients present at the stage when new vessels have already advanced across the macular region to the subfoveal area or where the fovea has already been permanently damaged by haemorrhage or exudate, making effective laser treatment impossible. Only about 10-20% of cases of CNV are eligible for laser photocoagulation. Another limitation of laser treatment is the high rate of recurrence of the CNV within a short time following treatment.
The second proven treatment is photo-dynamic therapy (PDT) with verteporfin (Visu-dyne). PDT specifically targets the CNV complex for damage by low-energy laser, but avoids damage to the unaffected tissue, including the photoreceptors. This treatment aims to preserve vision.
Apart from photocoagulation and PDT, there are other treatment modalities currently under investigation. These include radiotherapy, thermal thermotherapy and drugs including triamcinolone, anercortave, and vascular endothelial growth factor (VEGF) aptamers or antagonists, which are delivered via injections into the vitreous.
Practical measures can be taken in the management of these patients to alleviate their handicap. Telescopic lenses might be needed for reading or watching television and full consideration should be given to the question of blind registration. It is important to explain the nature of the condition and prognosis to the patient. This can alleviate considerable anxiety and fear of total blindness and help the patient come to terms with the problem. In most cases, one eye is involved first, the other following suit within one to three years. The vision, as measured on the Snellen chart, progressively deteriorates to less than 6/60, but the peripheral field remains unaffected so the patient is able to find his or her way about, albeit with some difficulty.
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