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Research - Age-related macular degeneration (AMD)

Photodynamic therapy
   

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'Wet' AMD arises when new blood vessels, known as choroidal neovascularisation (CNV), grow under the macula. These vessels can leak fluid, bleed and cause scar formation destroying vision in as little as three months. Clinician using a stereo camera to analyse images of the retina in 3D.

We have also been at the forefront of a new non-surgical procedure called photodynamic therapy (PDT)

Photodynamic therapy works by preventing the leaking vessels from doing further damage. The procedure is done in the outpatient clinic taking around 30 minutes and starts with a 10 minute intravenous infusion of Visudyne. This is a light sensitive dye that sticks to the inner lining of the new vessels. Five minutes after the end of the infusion the dye is activated by light shone onto the macula by the eye surgeon through a contact lens placed on the surface of the eye. The activated dye then damages the vessels causing them to close. The treatment often needs to be repeated after 3 months.

Photodynamic therapy is only beneficial for certain categories of CNV based on the appearances on fluorescein angiography and known as "predominantly classic", "pure classic" and "pure occult with high risk characteristics". These three varieties account for about 40% of all cases of wet AMD and nearly all cases caused by high myopia. For the first two of these types of CNV with the most aggressive course PDT needs to be commenced within 6 months of the onset of visual deterioration. It is not suitable for people with dry AMD or other causes of macular disease or for long-standing poor vision due to wet AMD

PDT has been shown to be far more effective for a far greater number of AMD patients than laser. Our research groups in Liverpool intend to keep at the forefront of this important breakthrough.

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