Phase 4 Study: Long-term Safety and Efficacy of NT-501 in MacTel Type 2, Including Sham Procedure Participants

This extension study consists of 3 arms: * Arm 1 (Phase 3 Treated Participants' Long-term Follow-up): Arm 1 is to assess the long-term safety and efficacy of NT-501 in participants who received NT-501 in a previous MacTel Phase 3 clinical study (NTMT-03-A or NTMT-03-B) and have retained at least 1 NT-501at study entry. * Arm 2 (Phase 1 and Phase 2 Long-term Follow-up): Similar to Arm 1, Arm 2 is to assess the long-term safety of NT-501 in participants who received NT-501 in a previous MacTel Phase 1 or Phase 2 clinical study (NTMT-01, NTMT-02, or NTMT-01/02E) and have retained at least 1 NT-501 at study entry. * Arm 3 (Phase 3 Sham to Implant Crossover): Arm 3 will evaluate the safety and efficacy of NT-501 in participants who previously underwent the sham procedure in a Phase 3 MacTel clinical study (NTMT-03-A or NTMT-03-B) and elect to have NT-501 implanted intraocularly in this extension study. Arms 1 and 2 are noninterventional and observational studies. For participants who previously received a single NT-501 implant, the implanted eye is designated the study eye. For participants who received an NT-501 in both eyes (ie, the first implant received in NTMT-01, NTMT-02, NTMT-01/02E, NTMT-03A, or NTMT-03B, and the second implant received in NTMT-02B), both eyes will be designated as study eyes. Only participants in Arm 3 will receive active intervention during this Phase 4 study. A participant can receive NT-501 in either eye that meets eligibility criteria according to investigator assessment, and in accordance with participant choice. However, if only 1 eye is eligible for implantation based on all inclusion/exclusion criteria, then that eye will be selected for NT-501 implantation. The eye selected for NT-501 implantation will be designated as the study eye. Regardless of study eye designation, both eyes of each participant in all 3 study arms will be evaluated during the study.