Objective: To examine the sensitivity of the multifocal electroretinogram (mf-ERG) at measuring changes in retinal electrical activity in response to Avastin (bevacizumab) treatment for age-related macular degeneration (ARMD).
Methods: Nine subjects with exudative ARMD, not previously treated with bevacizumab in the investigated eye, underwent pretreatment testing with mf-ERG and intravenous fluorescein angiography (IVFA). A second mf-ERG test was conducted post-treatment. The P1 response amplitudes were examined for the hexagons corresponding to areas of pathology on the IVFA. Intertest variability was accounted for by examining areas without pathology. Aggregate responses were also generated for central and lesion-associated responses.
Results: Changes in P1 response amplitude correlated with changes in visual acuity (R2>0.96). An improvement in Snellen visual acuity correlated with a significant improvement in P1 response amplitude from lesion associated recordings (p<0.03). Changes in P1 response amplitudes were not observed when aggregate responses were generated.
Conclusion: This study represents a novel method for assessing an improvement of mf-ERG responses. This is the first study to demonstrate a statistically significant change in retinal electrical activity postbevacizumab in patients with ARMD. This study demonstrates a method for utilising mf-ERG to assess changes in retinal electrical activity and to assess the effectiveness of treatments such as bevacizumab.
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This study was presented as a podium presentation at the 2007 Canadian Ophthalmology Society annual meeting in Montreal, Canada, and the methods were presented as a poster at the 8th Annual European Neuro-Ophthalmology Society Meeting in Istanbul, Turkey.
Funding: Financial support for this study was provided internally by the Department of Ophthalmology at Queen’s University.
Competing interests: None.
Ethics approval: The study was approved by the Queen’s University Research Ethics Board and complies with the Declaration of Helsinki.
Patient consent: Obtained.