Abstract
Purpose:
To investigate spectral domain optical coherence tomography (SDOCT) and microperimetry (MP) findings in patients before and after intravitreal bevacizumab or ranibizumab treatment for diabetic macular edema (DME), and to investigate their predictive value of SDOCT findings with regards to retinal functionas assessed with MP.
Methods:
Forty-five patients (59 eyes) with center-involving DME were randomly assigned to receive either 1.5 mg/0.06 cc intravitreal bevacizumab (IVB;33 eyes) or 0.5 mg/0.06 cc intravitreal ranibizumab (IVR; 26 eyes). Injections were performed at baseline and monthly if central subfield thickness (CSFT), measured by SDOCT, was 275 µm or higher. Evaluations including best-corrected visual acuity (BCVA) and SDOCT were performed monthly. MP (MAIA - CenterVue) was performed pre-injection and at 3, 6, 9 and 12 months of follow up to determine the fixation stability (95 % bivariate contour ellipse area - BCEA), and the sensitivity threshold (ST) on 37 test points. DME was classified using SDOCT as diffuse or focal, and by the presence or absence of cysts in the inner (cINL) or outter (cONL) nuclear layer, serous retinal detachment (SRD), and hyperreflective hard exudates (HE).
Results:
A significant (P<0.05) improvement in BCVA (logMAR) (IVB: 0.24 ± 0.16; IVR: 0.28 ± 0.19) and a significant reduction in CSFT (IVB: 121.6 ± 145.0 µm; IVR: 118.8 ± 122.6 µm) were observed, but there was no significant correlation between BCVA improvement and CSFT reduction within the IVB or IVR (IVB: r=0.29; P=0.11, IVR: r=0.24; P=0.24). There was a significant improvement in the ST in the IVB and IVR groups( 3.0 ± 0.6 dB and 2.7 ± 0.6 dB, respectively), but there was no significant change in BCEA in either group. Eighteen of the 59 eyes (31%) showed focal DME, and these eyes demonstrated a lower mean change in ST (1.4 ± 1.0 dB; P=0.088) compared to eyes with diffuse DME (3.4 ± 0.4 dB; P<0.001). Eyes with cINL (25%), cONL (66%), SRD (14%) or HE (47%) demonstrated a similar mean improvement in ST compared to eyes without these findings.
Conclusions:
This data indicate that anti-VEGF treatment is associated with diffuse, but not focal, DME. The presence of cINL, cONL, SRD or HE was not associated with the magnitude of ST improvement.
Keywords: 499 diabetic retinopathy •
505 edema •
748 vascular endothelial growth factor