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.
Severely coagulated retinae by argon laser of 20 Chinese hamsters were investigated with transmission electron-microscopy. The results revealed destruction of retinal pigment epithelium-Bruch's membrane-choroid capillary complex at the coagulated foci, and leakage of fluid and blood cells through the choroidal vessels into the subretinal space. Several days after laser burn the subretinal fluid was found to subside and the RPE cells surrounding the burned lesions started to proliferate. The smaller lesions were covered by the proliferating RPE 10 days after coagulation, but poor regeneration of RPE in large necrotic areas. Neovascularization was usually associated with obvious defect of Bruch's membrane and restoration of RPE barrier was most likely impossible. （Chin J Ocul Fundus Dis,1992,8:14-16）
The human sclera accounts for 95% of the surface of the eyeball, providing ample contact area which is suitable for targeted trans-scleral ocular drug delivery. Currently there are several tans-scleral sustained-release strategies, including intra-scleral delivery, episcleral delivery, as well as tans-scleral iontophoresis. Different devices and methods have their own advantages and disadvantages, for example, intra-scleral delivery is somehow invasive, and episcleral delivery device needs to be made thin to prevent erosion of conjunctiva, iontophoresis needs to be frequently repeated as of its short-term effect. With the development of bio-material engineering technology, episcleral microfilm could become an ideal drug delivery route for posterior segment ocular diseases.
OBJECTIVE:To elucidate the nature of degenerations in canine peripheral retina and compare the degenerations with those in human peripheral retina. METHODS: Examining randomly the peripberal fundus of eighty eye balls of forty dogs wdh dissecting microscope. The lesions of degenerations were photographed and processed for light microscopic examination. RESULTS:Typical Cystoid degeneralion,reticular degenerative retinoschisis, paving-stone degeneration, and lattice degeneration were discovered. The pathologic findings of these degenerations were same as or similar to those of the degenerations in human peripheral retina. CONCLUSIONS:The atrophic retinal degenerations that are similar to human' s are present at peripheral fundus in canine eyes. （Chin J Ocul Fundus Dis,1996,12: 151-152）