An Alternative and Validated Injection Method for Accessing the Subretinal Space <i>via</i> a Transcleral Posterior Approach

Abstract

Subretinal injections have been successfully used in both humans and rodents to deliver therapeutic interventions of proteins, viral agents, and cells to the interphotoreceptor/subretinal compartment that has direct exposure to photoreceptors and the retinal pigment epithelium (RPE). Subretinal injections of plasminogen as well as recent preclinical and clinical trials have demonstrated safety and/or efficacy of delivering viral vectors and stem cells to individuals with advanced retinal disease. Mouse models of retinal disease, particularly hereditary retinal dystrophies, are essential for testing these therapies. The most common injection procedure in rodents is to use small transcorneal or transcleral incisions with an anterior approach to the retina. With this approach, the injection needle penetrates the neurosensory retina disrupting the underlying RPE and on insertion can easily nick the lens, causing lens opacification and impairment of noninvasive imaging. Accessing the subretinal space via a transcleral, posterior approach avoids these problems: the needle crosses the sclera approximately 0.5 mm from the optic nerve, without retinal penetration and avoids disrupting the vitreous. Collateral damage is limited to that associated with the focal sclerotomy and the effects of a transient, serous retinal detachment. The simplicity of the method minimizes ocular injury, ensures rapid retinal reattachment and recovery, and has a low failure rate. The minimal damage to the retina and RPE allows for clear assessment of the efficacy and direct effects of the therapeutic agents themselves. This manuscript describes a novel subretinal injection technique that can be used to target viral vectors, pharmacological agents, stem cells or induced pluripotent stem (iPS) cells to the subretinal space in mice with high efficacy, minimal damage, and fast recovery.

Subretinal surgery: functional and histological consequences of entry into the subretinal space

“…; Wolff ; Parikh et al. ). Access through the sclera is commonly used in the subretinal implantation of retinal prosthesis (Lin et al.…”

Regulation of the Ocular Cell/Tissue Response by Implantable Biomaterials and Drug Delivery Systems

“…Due to its high precision and efficacy, the sub-retinal route is considered as one of the most effective methods used for ocular drug delivery [38]. The sub-retinal space can be typically accessed by the posterior trans-scleral route or trans-choroidal route (passing through the choroid and Bruch's membrane without penetrating the retina) [39][40][41][42][43][44].…”

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

“…Basically, approaches for subretinal injections can be divided into 3 groups: (1) a transcorneal route through the pupil, passing the lens, vitreous, and retina [105,106] ; (2) a transscleral route entering the pars plana or limbus areas, crossing through the vitreous and the opposite side of retina into the subretinal space [9,107,108] ; and (3) a transscleral route through the choroid and Bruch's membrane without penetrating the retina [109][110][111] ( Fig. 2 ).…”