Preliminary Study Of The Ttt Treatment Of Retinal Vein Occlusion

Objective:To observe the changes of morphologic and the connection of blood vessel in colored rabbits with branch retinal vein occlusion(BRVO) after therapy by Transpupillary Thermotherapy(TTT),and study the mechanismof TTT against BRVO.Methods:The experiments were performed on 24 colored rabbits(48 eyes) which were separated into three groups-normal group(8 eyes),model group(20 eyes),therapy group(20 eyes).Intravenous inject 5%rose Bengal stain and irradiate by 532nm laser on model and therapy group colored rabbits' retinal vein.Through fundus fluorescein angiography(FFA) to judge whether models were formed.And irradiate by 810nm laser on therapy group colored rabbits' retina after models were formed. Followed up by 3 weeks,fundus photograph,optic coherent tomography and light microscopy were observed.Results:â‘ Model:20 colored rabbits(40 eyes),34 eyes(85%) model were formed.Every rabbit received averagely 1.5 times laser irradiation.â‘¡Fundus observation:normal group rabbits retina were nomal;In model group 17 eyes,retina hemorrhage and edema were obvious,vessels disordered and neovascularization appeared in 15 eyes(88.24%).retinal hemorrhage was absorbed,neovascularization didn't appeared in 2 eyes(11.76%);In therapy group17 eyes,retinal hemorrhage was absorbed significantly and neovascularization didn't appeared in 14 eyes (82.35%).retina hemorrhage and edema were obvious,vessels disordered and neovascularization appeared in 3 eyes(17.65%).â‘¢OCT observation:therapy group colored rabbits' retina thickness were thiner than model group.â‘£Light microscopy: model retina appeared neovascularization,never fiber layer thinkened,tissue gap bordened,inner structures disordered.Ganglion cells decreased,showing vacuole.Inner nuclear cells decreased and shape largened.Outer five layers didn't change.Therapy group retina didn't appear neovascularization and inner five layers' damage didn't obviouser than model group.We found vessel connected retina and choroid in therapy group.Conclusion:â‘ TTT can promote the absorption of the hemorrhage significantly and prevent neovascularization in colored rabbits with the retinal vein occlusion.â‘¡The mechanism of TTT against BRVO might be that it relieve the high pressure in retinal vein by inducing chorioretinal venous anastomosis to protect the retina.