Alternative therapies in exudative age related macular degeneration

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Abstract
Age related macular degeneration (AMD) is the leading cause of blindness in the developed world.1 Vision may be lost as a consequence of choroidal neovascularisation (CNV), detachment of the retinal pigment epithelium (RPE), or geographic atrophy. Therapeutic efforts have been directed towards influencing the neovascular process, which is acknowledged to be the most common cause of visual loss. The beneficial effect of laser photocoagulation in well defined “classic” juxtafoveal and perifoveal CNV is well established and widely accepted.2 3 However, they comprise a small proportion of those with visual loss in clinical practice (<10%),4 and recurrence rates of up to 59% after treatment have been reported.5 At best, photocoagulation delays severe visual loss rather than representing a permanent cure in the majority of cases. The treatment of subfoveal CNV with laser is more controversial.6-8 Despite immediate loss of acuity, long term follow up of more than 2 years has shown benefit in patients with small new vessel complexes and poor visual acuity.9Nevertheless, the sudden acquisition of a dense central scotoma allows little time for the treated patients to adapt to the visual changes, and this treatment has yet to become widely practised. There is clearly a need for new forms of treatment for subfoveal CNV in AMD, and many alternative approaches have been considered. This review outlines the current status of these alternative therapies. The rationale of radiation therapy is based on the observation that growing blood vessels are more sensitive to damage by ionising radiation than mature vessels,10 so that new vessels may become non-perfused without damage to surrounding tissue. This can be achieved by either an external beam (teletherapy) or an episcleral plaque (brachytherapy). In 1993, Chakravarthy and colleagues first reported a study of external beam radiation therapy in 19 …