Severity of Diabetic Macular Edema does not influence Restoration of Retinal Photoreceptor Ellipsoid Zone after Intravitreal Bevacizumab Therapy

Purpose: To evaluate the influence of severity of diabetic macular edema (DME) in restoration of retinal photoreceptor ellipsoid zone (EZ) on spectral domain optical coherence tomography (SD-OCT),after intravitreal bevacizumab therapy (IVB), in patients without chronic kidney disease (CKD).

Materials and Methods: Consecutive cases of type 2 diabetes mellitus (n=44), having EZ disruption on SDOCT,between the ages of 40 and 65 years, were included. Cases with CKD were excluded.The cases were divided into six different clusters based on their macular thickness (central subfoveal thickness, CST); Cluster 1:250- 300µm,Cluster 2:301-350µm, Cluster 3:351-400µm, Cluster 4:401-450µm, Cluster 5:451-500µm and Cluster 6:501-550µm. EZ disruption was graded on SD-OCT as following: Grade 0,Intact EZ ; Grade 1, Focal disruption (localized subfoveal involvement); Grade 2,Global disruption (generalized involvement within macular cube). Pretreatment CST was correlated with restoration of EZ, after three doses of IVB therapy on monthly basis. Data was analyzed statistically.

Results: Decrease in logMAR VA was significant after IVB regimen from pre-treatment level of 1.78±0.07 to 0.42±0.05post intervention (p<0.001). Similarly, CST decreased significantly from pre-treatment level of 354.23±15.0 to 233.18±7.88 post intervention (p<0.001). EZ restoration in each cluster was found to be independent of the initial CST (p>0.05). 

Conclusions: Intravitreal bevacizumab regimen is associatedwith restoration of EZ, which is independent of pretreatment CST on SD-OCT, in cases of DME without CKD.