The suprachoroidal space (SCS) is the potential space between the sclera and choroid. Drugs delivered through SCS can bypass the sclera, avoiding clearance by conjunctival and scleral blood vessels and lymphatic circulation, so that more drugs can reach the disease tissues such as choroid and retina. SCS drug delivery does not disrupt the ocular integrity, is safer than the intravitreal drug injection and more effective than trans-scleral drug delivery. In addition, SCS delivery only needs a very small volume of drug, which makes it possible to be carried out in multiple parts of the sclera, and the specific disease area can be more precisely targeted. SCS drug delivery is suitable for the treatment of choroidal and retinal diseases. However, currently SCS drug delivery is still a novel field and many aspects need to be more in-depth studied, including its safety, delivery methods, drug formulation and effectiveness.
ObjectiveTo observe the retinal reattachment of suprachoroidal injection with sodium hyaluronate in the treatment of rhegmatogenous retinal detachment (RRD).MethodsTwelve eyes of 12 patients with RRD diagnosed by the examinations of B-mode ultrasound, binocular indirect ophthalmoscope, OCT and scanning laser ophthalmoscope in West China Hospital of Sichuan University from October 2018 to February 2019 were included in this study. There were 7 males and 5 females, aged from 15 to 66 years, with the mean age of 32.40±14.81 years. There were 4 eyes with BCVA＜0.1, 4 eyes with BCVA 0.1-0.4, 4 eyes with BCVA＞0.4. The extent of retinal detachment involves 1 to 4 quadrants. All eyes were injected with sodium hyaluronate via suprachoroidal space under non-contact wide-angle system. Surgery was performed by the same ophthalmologist with extensive surgical experience. During the operation, the retinal hole was handled with scleral freezing and laser photocoagulation. The follow-up was 2 months. The retinal reattachment was observed.ResultsOf the 12 eyes, 6 eyes (50.00%) were anatomically reattached, 4 eyes (33.33%) ere partly anatomically reattached with subretinal fluid, 2 eyes (16.67%) were not reattached. The holes in 4 eyes of partly anatomically reattached with subretinal fluid were located on the choroidal pad and the holes were closed, in addition, the subretinal fluid gradually absorbed over time. Two eyes failed in retinal reattachment received vitrectomy with silicone oil tamponade or sclera buckling surgery. No severe complications such as endophthalmitis and choroidal hemorrhage were found at follow-up visits.ConclusionSuprachoroidal injection of sodium hyaluronate is an effective and safe treatment for RRD, which can promote retinal reattachment.
The suprachoroidal space is a potential space between the sclera and choroid. Suprachoroidal spacedrug delivery is becoming an applicable method to the ocular posterior segment diseases. Because it targets the choroid, retinal pigment epithelium and retina with high bioavailability and safety, while maintaining low levels elsewhere in the eye. In recent years, new discoveries has been carried out in different areas of interest, such as drug delivery methods, pharmacokinetics and clinical trials. Clinical trials with suprachoroidal space injection of triamcinolone acetonide are executed with promising findings for patients with noninfectious uveitis and diabetic macular edema. Suprachoroidal space triamcinolone acetonide injectable suspension is the first and currently the only agent specifically approved for uveitic macular edema by Food and Drug Administration. Nowadays, many clinical trails with suprachoroidal space drug delivery have been explored, although there are still many risks and uncertainties. With the development of technology in the future, suprachoroidal space drug delivery appears to be a promising treatment modality for ocular posterior segment diseases.
Gene therapy is designed to introduce genetic material into the cells of a patient via virus to enhance, inhibit, edit or add a genetic sequence, results in a therapeutic or prophylactic effect. Gene therapy has brought positive influence and great potential for the treatment of retinal diseases including genetic retinal diseases and acquired retinal diseases. In addition to the constant optimization of gene vectors, the exploration of different drug delivery techniques has brought different therapeutic effects for gene therapy of retinal diseases. The main delivery methods include subretinal injection, intravitreal injection, suprachoroidal injection. Considering the transfection efficiency and safety of delivery methods, emerging sub-inner limiting membrane injection and noninvasive gene delivery are under investigation. The selection of gene delivery method is very important for the safety and effectiveness of gene therapy for retinal diseases. It is not only related to the development of equipment and technology, but also related to the modification of adeno-associated virus, the selection of promoter and the specific retinal cells that the target gene wants to be transfected. Therefore, the most appropriate method of gene delivery should be selected according to the final gene therapy agent and the specific transfected cells after taking all these factors into consideration.