Abstract:
Purpose: To investigate retinal ultrastructural, electrophysiological, and microvascular
morphological changes, as well as correlations between these changes and visual outcome in naïve
diabetic macular edema (DME) patients after intravitreal bevacizumab therapy
Design: A prospective interventional study
Methods: A total of 31 DME patients’ eyes had monthly intravitreal bevacizumab injections for
three consecutive months. Best-corrected visual acuity (BCVA) and intraocular pressure (IOP)
were measured, and fundus fluorescein angiography, optical coherence tomography (OCT),
microperimetry (MP), as well as optical coherence tomography angiography (OCTA) were
performed before and after therapy. Patients were then grouped based on BCVA improvement
after three consecutive intravitreal injections: group 1- >10 letters, group 2- ≤5 letters, and group
3- between 6 and 10 letters.
Results: Mean BCVA increased significantly after therapy, rising from 34.2 to 39.9 letters
(p<0.001). The central macular thickness (CMT) decreased significantly from baseline 335.1 μm
to 276.4 μm (p<0.001). Fixation stability, mean retinal sensitivity, and mean local deficit all
improved significantly after therapy (p<0.001 for all). There was no statistically significant change
in IOP before and after therapy (p=0.665). While OCTA parameters did not change significantly,
patients with lower foveal avascular zone area, higher FD-300 and deep plexus vascular density
showed better improvements in mean BCVA, retinal sensitivity, and local defect. Also, there were
no significant intergroup differences in gender, age, baseline BCVA, HbA1c, IOP,
phakic/pseudophakic lens ratio, presence of concomitant hypertension, and superficial capillary
plexus vascular density.
Conclusions: Intravitreal bevacizumab therapy was associated with significantly improved
BCVA, retinal ultrastructural integrity, and electrophysiological patterns in naive DME patients.
Improvements in retinal electrophysiology correlated with ultrastructural improvements, which
could be predicted using OCTA.
