Subretinal Injection: A Review on the Novel Route of Therapeutic Delivery for Vitreoretinal Diseases

Compared to intravitreal injection, subretinal injection has more direct effects on the targeting cells in the subretinal space, which provides a new therapeutic method for vitreoretinal diseases, especially when gene therapy and/or cell therapy is involved. To date, subretinal delivery has been widely applied by scientists and clinicians as a more precise and efficient route of ocular drug delivery for gene therapies and cell therapies including stem cells in many degenerative vitreoretinal diseases, such as retinitis pigmentosa, age-related macular degeneration, and Leber's congenital amaurosis. However, clinicians should be aware of adverse events and possible complications when performing subretinal delivery. In the present review, the subretinal injection used in vitreoretinal diseases for basic research and clinical trials is summarized and described. Different methods of subretinal delivery, as well as its benefits and challenges, are also briefly introduced.