Susvimo was to be given via a refillable implant inserted into the eye. This implant was designed to release the medicine into the eye over time and to be refilled every 6 months by a doctor specialised in eye care. 

The active substance in Susvimo, ranibizumab, is a small piece of a monoclonal antibody (a type of protein that has been designed to recognise and attach to a specific target called an antigen). 

Ranibizumab attaches to and block a substance called vascular endothelial growth factor A (VEGF-A). VEGF-A is a protein that makes blood vessels grow and leak fluid and blood, damaging the macula. By blocking VEGF-A, ranibizumab reduces the growth of the blood vessels and controls the leakage and swelling.