Abstract
Purpose: :
To evaluate the effects of intravitreal bevacizumab injections on diabetic macular edema (DME) by the type of macular edema.
Methods: :
A total of 82 eyes with refractory DME were enrolled. The DME was classified into diffuse, cystoid, and serous type by optical coherence tomographic finding. All cases had received an intravitreal injection of 1.25mg/0.05ml bevacizumab every month for three times. A foveal thickness and macular volume were measured with optical coherence tomography before and one month after the third injection, and same times the best corrected visual acuity was measured. The interval changes of the foveal thickness, macular volume, and visual acuity were compared and analyzed with SPSS.
Results: :
The types of DME were diffuse (41 eyes, 50%), cystoid (26 eyes, 31.7%), and serous (15 eyes, 18.3%) edema. The pre-injection mean values of the foveal thickness of the diffuse, cystoid, and serous DME were 276.9+60.9µm, 341.3+112.9µm, 368.6+151.9µm, the post-injection values were 272.0+88.4µm, 267.2+54.6µm, and 289.3+119.6µm. The post-injection foveal thickness decreases were significant at all three types. The decreases of the foveal thickness of the cystoid and serous DME were more significant compared to that of the diffuse type. The pre-injection mean values of the macular volume of the diffuse, cystoid, and serous DME were 7.96+0.80mm3, 8.16+1.72mm3, and 8.93+2.68mm3, the post-injection values were 7.81+0.93mm3, 7.48+0.94mm3, and 8.26+1.58mm3. The post-injection macular volume decreases were significant in all three types of DME. But there was no statistical difference among the groups in the amount of macular volume decrease. The pre-injection mean values of visual acuity of the diffuse, cystoid, and serous DME were 0.40+0.46logMAR, 0.51+ 0.38logMAR, and 0.49+0.28logMAR, the post-injection values were 0.34+0.33logMAR, 0.48+0.47logMAR, and 0.47+0.31logMAR. The post-injection vision improvements were not statistically significant in all three types of DME. And also there was no difference among the groups in the amount of vision improvement.
Conclusions: :
There were significant decreases of the foveal thickness and macular volume after intravitreal injections of 1.25mg bevacizumab. More significant decreasing effects were found in the cystoid and serous type of DME compared to diffuse type. There was no statistically significant improvement of visual acuity after intravitreal injections.
Keywords: diabetic retinopathy • injection • vitreous