¡¡¡¡The change in retinal thickness was correlated to change in visual acuity using the Pearson r test. At last followª²up (mean 4.7 months) compared to baseline, there was a moderate correlation between retinal thickness decrease and improvement in visual acuity (r£½0.43).

¡¡¡¡DISCUSSION

¡¡¡¡Although laser and steroid treatment for patients with BRVO have had statistically significant benefits in terms of retinal thickening and visual acuity, there are crucial shortcomings with these treatment options. With macular grid laser treatment, visual acuity gains were marginal and multiple treatment of were often needed[1,2]. In patients with significant macular hemorrhages, treatment must be deferred until there is significant clearing of these hemorrhages.

¡¡¡¡Treatment results after triamcinolone injection have been encouraged. However, significant adverse side effects have been associated with triamcinolone, including elevated intraocular pressure, increased rate of cataract formation, and increased risk of endophthalmitis. In addition, the durability of this treatment is in question[6].

¡¡¡¡Using intravitreal bevacizumab £¨Avastin£©we have observed a positive biologic effect on ME in patients with BRVO disease. VEGF, a key mediator of intraocular neovascularization and ME, is triggered by hypoxia and has been shown in the eyes of animal models of CRVO[11ª²14]. Therefore inhibition of VEGF could theoretically offer a therapeutic advantage. Consecutive eyes with BRVO treated with intravitreal bevacizumab in this study demonstrated both anatomic and functional improvement. Patients showed a marked decrease in ME and an improvement in visual acuity, even though most previously had a poor response to intravitreal tramcinolone. We did not find any observable side effects with intravitreal bevacizumab such as inflammation, infection£¬increased intraocular pressure, retinal tear, or detachment. Compared with baseline, mean visual acuity improved at 1 month, 3 months, and last followª²up. In addition, 47% experienced a halving of the visual angle at the close of data collection. The mean retinal thickness underwent the greatest reduction at 1 month and remained stable at 3 months and last followª²up. These changes in retinal thickness moderately correlated with changes in visual acuity (r£½0.43), similar to what has been suggested in patients with diabetic ME. Factors impeding vision improvement are likely to be related to the length of time ME was present before treatment with intravitreal bevacizumab£¬and the presence and severity of macular ischemia. Comparison of visual acuity improvement between eyes with complete perfusion and some or complete nonperfusion, however, suggests that the prognosis for vision improvement is relatively the same for both groups.

¡¡¡¡The use of intravitreal bevacizumab for BRVO offers significant advantages over triamcinolone and gridª²laser treatment. In shortª²term studies, elevated intraocular pressure and early cataract formation have not been shown to be associated with bevacizumab injections[8]. In addition, systemic adverse events due to intravitreal bevacizumab injection have thus far not been reported, although they are theoretically possible. This is important, as multiple treatments of bevacizumab are necessary in some patients. The ration of the observed anatomic and visual acuity changes is variable.

¡¡¡¡In cases of severe intraretinal hemorrhages, an obstructed view of the fundus does not allow for immediate treatment with laser. Avastin treatment can be initiated immediately while waiting for the hemorrhage to clear before initiating laser treatment. Avastin may also prevent the development of neovascularization[15].

¡¡¡¡Consecutive eyes with ME due to BRVO treated with intravitreal bevacizumab in this retrospective study demonstrated both anatomic and functional improvement. Patients showed a marked decrease in macular edema and an improvement in visual acuity, even though most previously had a poor response to laser or intravitreal tramcinolone. No observable side effects were found with intravitreal bevacizumab such as inflammation, infection£¬increased intraocular pressure, retinal tear, or detachment. The shortcomings of this retrospective review, limited followª²up, small sample size, lack of control group, and nonª²standardized visual acuity testing, preclude any estimation of the longª²term efficacy or safety intravitreal bevacizumab.
¡¡¡¡Additionally, most of the eyes in the study were previously treated eyes and thus failed standard treatment, perhaps being a group unlikely to benefit from any treatment. Despite these limitations, the results were very promising and show the need for further investigation of this agent.

ÉÏÒ»Ò³  [1] [2] [3] [4] ÏÂÒ»Ò³