Central retina vein occlusion and diabetic retinopathy treated with intravitreal dexamethasone and bevacizumab: a morpho-functional analysis

Abstract

Purpose: To follow-up the effect of multiple intravitreal injections of dexamethasone and bevacizumab in the macular edema (ME) affecting subjects suffering from Central Retina Vein Occlusion (CRVO) and Diabetic Retinopathy (DR): analysis via optical coherence tomography (OCT), multifocal electroretinogram (mfERG), focal electroretinogram (FERG), pattern electroretinogram (PERG) and patterned visual evoked potentials (pVEP).

Methods: We followed-up 6 patients affected by macular edema due to CRVO and 6 due to DR that were treated with intravitreal injections of dexamethasone and bevacizumab respectively from 1 to 3 times. All the patients had a complete ophthalmologic visit and functional analysis including OCT, mfERG, FERG, PERG and pVEP. Visual acuity (VA) by mean of logMAR octotypes, latencies and amplitudes of the functional tests (i.e. 9 OCT areas, the 5 mfERG rings, a and b FERG waves, P50 and N95 PERG waves, P100 pVEP wave values among others) were collected and statistically analyzed.

Results: The results between groups were not linear. Compared to an OCT higher basal thickness in CRVO subjects respect to DR ones (371.07 versus 275.83), the mean VA was better in the first ones (0.2 logMAR respect 0.45). After intravitreal injections the mean mfERG amplitudes increased more in the OVCR group (43±7 nanovolts) respect the DR one (23±8). The mfERG amplitudes increased in all the rings in the first control after treatment and tended to decrease in the second one, also if do not come back to the initial outcome. The FERG had a significant b amplitude improvement (P≤0.05) in DR subjects. PERG and pVEP latencies and amplitudes do not changed significantly, but had an improvement in 4 CRVO subjects respect to 2 DR. The results were stable in 1 CRVO and 2 DR group and were worse in 1 CRVO respect to 2 DR.

Conclusions: Intravitreal dexamethasone and bevacizumab injections, like other new drugs for the retinal edema rescue, are a great opportunity in ophthalmologic therapy. It is likely that the results are connected to the pathology level and the degree of photoreceptors damage. Probably DR, particularly in the proliferative shape, imply a deeper inner retinal layers damage than CRVO.

Keywords: 507 electrophysiology: clinical