The Animal Experiment And Clinic Study Of Transpupillary Thermotherapy

【Purpose】Transpupillary thermotherapy is an effective method for age-related macular degenereation.But its therapeutic mechanism and detailed parameter is stilled to,founded.This animal experimental aim is to study the microscopic tissue structure and retionchoroidal changes on the condition of the different power of TTT,and provide instructive and theorotical evidence for its clinical pratice.On the base of it,the aim of clinical study is to evaluate the effect of transpupillary thermotherapy for the treatment of choriodal neovascularization secondary to age-related macular degeneration and influence on vision.1.The Effect of TTT on pigmented rabbits retinal【Method】Eight pigmented rabbits were divided into eight groups(control group, 70mw,100mw,150mw,200mw,250mw,300mw,350mw group)by different power of TTT randomly,while duration and beam spot diameter of TTT were fixed at 60s and2.0mm respectively.A series of laser pulses were aimed at the posterior of retinal and the lower edge of the myelinated nerve fibers.Rabbits were sacrificed at 24 hours after photocoagulation.All the eyeballs were imbeded in paraffin.Then they were dyed by HE dying,HSP70 immunohistochemistry dyeing.【Result】In the normal control group,the retinal tissue structure is normal,and there is negative of HSP70 immunohitochemistry dying.There is no visible changes on irridiated spots with 100mw,150mw and HSP70 appeared in retinal ganglion cell layer.There is positive of HSP70 immunohitochemistry dying with 200mv and the irridiated spots are a little grey.There is negative of HSP70 immunohitochemistry dying on 250mw,300mw,350mw group.【Conclusion】With subthreshold power,TTT can induce the expression of HSP70.HSP70 is useful for the prevention injury of retinal ganglion cell layer.The irridiated spots can reflect the safety of parameter of TTT.2.The Clinic Study of TTT on Age Related Macular Degeneration【Method】We conducted a retrospective review of patients with choroidal neovascularization secondary to the age-related macular degeneratio treated with TTT from July,2005 through December,2007.44 patients took part in this study.36 cases in experiment group,8 cases in control group.The experiment group were dealed with TTT.The control group was dealed with vitamins.One month later,outcome was assessed with standard international visible acuity table and FFA.Re-treatment was performed if indicated.【Result】The 36 eyes of age-related macular degenereationg was examimed by FFA,the CNV membrines were totally closed in 2/36 eyes(5.6%),partly closed in 25/36 eyes(69.4%),and remained persistent in 9/36 eyes(25.0%).After the second TTT,20 eyes were examined again,the CNV membrines were totally closed in 1/20 eye(5.0%),partly closed in 15/20 eyes(75.0%),and remained persistent in 4/25eyes(20.0 %).There is no significant difference between the first TTT and the second TTT(P＞0.05).Patients had a mean follow-up of 6 months.In experiment group,vision improved greater than one line in 11 eyes(30.5%),vision was stable in 23 eyes(63.9%),and worsened greater than one line in 2 eyes(5.6%).In control group,no vision improved,vision was stable in 1 eye(12.5%),and worsened in 7 eyes(87.5%).It has significant difference in vision between experiment group and control group(P＜0.05).And It has also significant difference between pretreatment and post treatment(P＜0.05).【Conclusion】Transpupillary thermotherapy is an effective treatment for macular diseases,with using subthreshold power,it is able to close choroidal neovascularisation while maintaining visual function in patients with age-related macular degeneration.The second TTT is useful for closing choroidal neovascularisation and no injury to vision.