Intravitreal Tissue Plasminogen Activator And Perfluoropropane for Neovascular Age-related Macular Degeneration With Associated Submacular Haemorrhage: a Multi-centre, Randomized, Double-masked, Sham-controlled, Factorial, Feasibility Study

Age-related macular degeneration (AMD) is the commonest cause of blindness worldwide. Its prevalence increases with age, being relatively rare under 60 years and reaching its peak incidence in those older than 80 years. AMD principally affects central vision, which is responsible for the ability to see fine detail and the disease rapidly destroys the ability to read normal print, recognise faces, drive, and watch television. It can therefore have a profound effect on quality of life.

There are two main forms of AMD; the dry form, in which there is slow degeneration of the cells responsible for sight, resulting in gradual visual loss; and the wet form (neovascular), which occurs when abnormal blood vessels (choroidal neovascularisation) grow under the retina, the part of the eye which is responsible for sensing light, like the film of a camera. These new blood vessels have weak walls leading to leakage of fluid (oedema), and sometimes significant amounts of bleeding (submacular haemorrhage - SMH). These rapidly lead to central visual distortion and blurring. Although the dry form is commoner, the wet form more commonly results in profound central visual loss and is responsible for the majority of cases that ultimately require blind registration.

The current best treatment ('gold-standard') for wet AMD is the drug ranibizumab (Lucentis®), which aims to shrink and destroy the abnormal blood vessels responsible for the visual symptoms. In several trials ranibizumab has been shown to improve vision in patients with wet AMD.

It is not uncommon for patients with wet AMD to develop SMH, which when it occurs, significantly reduces the patient's visual prognosis. SMH is thought to have a number of toxic consequences on the retinal function.

This study investigates the use of two drugs: tissue plasminogen activator (tPA), a 'clot-buster' drug used to treat stroke, which is designed to dissolve the clot over the central retina (macula); and perfluoropropane (C3F8), a gas commonly used in retinal surgery, which is designed to displace the clot away from the macula.