Abstract
Purpose: :
To investigate the morphological and functional changes of the macular oedema by Optical Coherence Tomography (OCT) and multiple visual acuity and electrophysiology examinations after recurrent intravitreal injections of bevacizumab.
Methods: :
twenty-six eyes of 26 patients with macular oedema due to vein occlusion or diabetic retinopathy received one (26 subjects) or two times ( 14 of 26 subjects) 1.25 mg bevacizumab intravitreal injections . All patients were submitted to complete ophthalmic examination including: ETDRS visual acuity, OCT scanning, transient and steady-state patterned electroretinography (PERG) and visual-evoked potentials (VEP) registered at the same time, 30 hz Electroretinography(ERG). These tests were iterated at baseline, 1 month and 2 months after injection. The results were evaluated by means of multiple statistical analysis comprehending regressions and "p" values.
Results: :
At baseline the mean central retinal thickness was 525.56[125] microns, at 1 month 355[118] microns and at three months 307[127] microns, showing a statistically significant reduction in both controls (p<0,0001). Mean log-mar visual acuity varied from 0.3 [0.21] at baseline to 0.41[0.26, p<0,001] on the first step and 0.36[0.26] at three months, with an improvement on the first control and a partial regression in the second . ERG 30 hz harmonic and patterned VEP did not shown significant variations. PERG P50 had not significant variations in latencies and amplitudes as well , while transient PERG N95 demonstrated an improvement of latency from baseline 125.53 [19.6] to 1 month 116.2[13.5] and confirmed at three month step 107.7[11.47, p<0.007] .
Conclusions: :
In our sample, intravitreal injections of bevacizumab produce a reduction of central retina thickness ,an improvement of visual acuity and of the PERGN 95 latency. PERG N95 gain could indicate a recovery of functional contrast component of the ganglion cells due to the reduction of oedema, confirmed by the subjective acuity rising, not always consistent with ETDRS gain amount . Repeated intravitreal injections of bevacizumab didn’t shown toxic effects.
Keywords: electrophysiology: clinical • diabetic retinopathy • vascular occlusion/vascular occlusive disease