Macular Telangiectasia type 2 leads to a gradual deterioration of central vision, which becomes noticeable to people around 40-50 years of age. MacTel has a significant impact on quality of life as central vision is required for tasks that require sharp vision like reading and driving. This study will test whether Renexus can be used to treat MacTel as there are currently no effective treatments available. Renexus is a small capsule of cells that is placed inside the eye to allow the release of Ciliary Neurotrophic Factor (CNTF) directly to the retina, the light sensitive part of the eye. The Renexus capsule (about the size of a grain of rice) contains living cells. These cells have been genetically modified to continuously release CNTF. “Genetically modified” in this case means that a small circle of DNA has been added to the cells so that they can make CNTF. We believe that CNTF works by helping sick cells in the retina survive. In an earlier study, some participants with MacTel seemed to do better as compared to participants who did not receive the Renexus implant. The aim of this study is to repeat that early study to see if the results can be confirmed. This study is called a phase 3 study. A total of 112 participants will be enrolled in this study at sites in the United States, Europe including the United Kingdom and Australia. Approximately 10-20 participants will be enrolled at this site here in the UK.