Abstract
Purpose:
To evaluate long-term changes in neuroretinal function by multifocal electroretinogram (mfERG) recordings in patients with exudative age related macular degeneration (ARMD) undergoing ranibizumab treatment.
Methods:
Fifty-seven patients with exudative ARMD naïve to the treatment were enrolled in this prospective, interventional longitudinal study. The patients who met the inclusion criteria were treated by monthly injections of intravitreal ranibizumab over 3 months and PRN regimen during the follow-up period of at least 12 months. At baseline all patients underwent fluorescein angiography, optical coherence tomography, best-corrected visual acuity (BCVA) assessment and mfERG. In all monthly visits, BCVA and OCT were performed. In addition, mfERG recordings were obtained at month 1, 2,3, 6,9 and 12. The study adhered to declaration of Helsinki.
Results:
Fifty-one patients completed the study. Mean injection rate over the one year was 5.7. BCVA improved from logMAR 0.57 to 0.50. Macular thickness decreased from 385 μm to 265 μm at month 12. Recording of mfERG P1 amplitude density of central macular zone was increased from 36.4 nv/deg2, to 42.5 nv/deg2 at month 6, 52.1 nv/deg2 at month 9 and 45.6 nv/deg2 at month 12. Improvements in BCVA and OCT were statistically significant in all measurement points. Recordings of mfERG was started to improve statistically at month 6 but this improvement was started to decrease at month 12. There was a positive correlation between BCVA and P1 amplitude value at baseline and month 12. Central electrophysiological recordings did not differ among the fluid configurations on OCT.
Conclusions:
While BCVA and macular thickness improves in even early term in response to the ranibizumab treatment, improvement in neuroretinal function takes a longer time in patients with exudative ARMD. A tendency of re-decline in mfERG at month 12 may represent early warning of visual dysfunction due to damage to the external retinal layers occurring in the long-term stage of the disease process.
Keywords: 412 age-related macular degeneration •
509 electroretinography: clinical •
754 visual acuity