| Background: Age-related macular degeneration is a diseases which characterized by drusen deposited between retinal pigment epithelium and choroidal is dry AMD, then induced choroidal neovascularization (CNV) is wet AMD, often leads to severe central visual impairment. Wet AMD is the primary causes of vision loss with people over 50 in developed countries, as well as our country increasingly aging population, improving healthcare, more and more Chinese patients are suffered from wet AMD. With further study, we come to realized that the incidence of wet AMD not only has a complex genetic basis, but also effected by environmental factors. For example, many investigators have basically reached a consensus for the view that smoking, sunlight, high blood pressure, PLEKHA1-LOC387715-HTRA1 and CFH gene polymorphism and other risk factors may be associated with the incidence of wet AMD. As the cause of wet AMD is complexes,the traditional laser photocoagulation, transpupillary thermotherapy and photodynamic therapy of wet AMD exist in their own deficiencies. Now, many researches showed that angiogenesis factors and vascular inhibitors imbalance is the most important cause leading to CNV, VEGF is the most potent angiogenic factor, so anti-VEGF treatment for control CNV has become a hot topic in wet AMD, such as intravitreal injection of anti-VEGF agent(Bevacizumab). Despite there are a lot of AMD-related investigations on the epidemiology and intravitreal injection of Bevacizumab in the world, but it is lack of Chinese patients'data. Therefore, collection of wet AMD patients and their matched non-AMD patients in case-control study for defined risk factors of wet AMD, and choose right patients with wet AMD to receive intravitreal injection of Bevacizumab for assess its efficacy and safety. It will be benefit for awareness possible risk factors of wet AMD, amplify the knowledge of its pathogenesis, find a suitable intervention targets, establish clear treatment options and to improve the prevention of wet AMD in China.Objective: To study the epidemiological characteristics of wet age-related macular degeneration, search for the possible risk factors associated with it, and evaluate the efficacy and safety of intravitreal injection of Bevacizumab for wet age-related macular degeneration.Methods: Eighty-four patients with wet AMD and seventy-eight age and sex matched patients without AMD diagnosed at our clinic between June 2008 and October 2009 were assessed in this consecutive study. Collected the information of epidemiology and related eye examinations for all the patients and carried out epidemiological information statistics. Using X2 test and multivariate Logistic regression model analysis to selection the risk factors which are lead to wet AMD. Further selected 16 patients (17 eyes) from the 84 wet AMD cases who are fit to treat with intravitreal injection of Bevacizumab(1.25mg/0.05ml), 8 times injection with interval 6-weeks, and then each interval of 6 weeks, 4 weeks of follow-up. Ophthalmologic evaluations include slit-lamp biomicroscopy, direct ophthalmoscopy examination. And intraocular pressure, best corrected visual acuity (BCVA), central macular thickness (CMT), the maximum lesion thickness are measured.Results: The average age of wet AMD patients was 69.47±8.24 years old, there were forty-eight male and thirty-six female and the average age of non-AMD patients was 68.84±8.58 years old, there were forty-five male and thirty-three female. After single factor analysis, there are smoking (X1), hypertension (X2), light (X3), BMI (X4), albumin (X5), homocysteine ( X6) and vitamin B12 (X7) access to the multivariate logistic regression model analysis. Smoking (OR = 0.03,95% CI = 0.37), homocysteine (OR = 0.04,95% CI = 0.34), vitamin B12 (OR = 0.03,95% CI = 0.37) are significant risk factor in wet AMD. After Intravitreal injection of Bevacizumab, mean BCVA from 55.36±10.49 letters at baseline,improved to 61.47±14.12 letters, 64.73±14.38 letters, 69.35±11.60 letters, 65.72±13.95 letters, 64.98±14.57 letters, 64.48±15.01 letters, 63.76±15.72 letters, 63.05±16.36 letters, 62.56±16.53 letters at every follow-up;mean CMT and maximum thickness lesions from 405.38±142.49μm and 320.98±114.59μm at baseline respectively, decreased to 397.21±137.82μm and 303.38±116.34μm, 386.10±140.33μm and 295.54±120.49μm, 364.18±121.60μm and 277.82±108.60μm, 358.72±138.48μm and 275.12±117.16μm, 359.12±109.51μm and 273.82±102.59μm, 360.02±135.27μm and 277.10±98.36μm, 363.16±112.31μm and 273.92±110.56μm, 372.18±104.35μm and 273.01±132.59μm, 377.96±116.53μm and 279.49±112.65μm at every follow-up. Only few patients have response of minor uveitis or short-term high intraocular pressure, there is no serious eye or systemic complications.Conclusion: Smoking, high serum homocysteine levels and low vitamin B12 levels may increase the risk of AMD, smoking cessation, vitamin supplements and other interventions may have a preventive role in wet AMD. Intravitreal injection of Bevacizumab for wet AMD can significantly improve visual function in patients, reducing macular thickness and CNV leakage, and no sever side effects, but need repeated treatment, so it still needs multi-center, large sample randomized controlled study.
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