Neovascular age-related macular degeneration (nAMD), also known as wet AMD, is the abnormal growth of new blood vessels in the light-sensitive tissue at the back of the eye called the retina. The purpose of this study is to assess how safe and effective Surabgene Lomparvovec is in treating participants with Neovascular age-related macular degeneration (nAMD). Surabgene Lomparvovec (ABBV-RGX-314) is an investigational gene therapy being developed for the treatment of neovascular age-related macular degeneration (nAMD). Participants will be placed into 1 of 3 groups, called treatment arms. Each group receives different treatment. Adult participants aged 50 and older years with a diagnosis of previously treated nAMD will be enrolled. Around 561 participants will be enrolled in the study at approximately 150 sites worldwide. Participants in groups 1 and 2 will receive a single subretinal dose of ABBV-RGX-314. Participants in group 3 will receive Ranibizumab as needed throughout the study. Ranibizumab will be given as an intravitreal injection (injection into the jelly-like tissue that fills the eyeball injection), and ABBV-RGX-314 will be given as a subretinal (between the retina and the back of the eye) injection. The Assessment Period begins after randomization (1:1:1) to one of the ABBV-RGX-314 treatment groups or control at Week -2 and lasts up to 5 years. There may be higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular monthly visits during the study at a hospital or clinic. The effect of the treatment will be checked by medical assessments, blood tests, checking for side effects and completing questionnaires.