The implants have a calculated half-life of more than 4 years, as judged from CNTF levels in the vitreous [76], and their ability to attenuate retinal degeneration is being tested in patients with diverse retinal disorders [55,77,78], including glaucoma (www.clinicaltrials.gov, NCT02862938). The gene discussed is CNTF; the disease is retinal degeneration.