Detection of early age-related macular degeneration using novel functional parameters of the focal cone electroretinogram

The focal cone electroretinogram is a sensitive marker for macular disease, but have we unlocked its full potential? Typically assessment of waveform parameters is subjective and focuses on a small number of locations (e.g. the a-wave). This study evaluated the discriminatory and diagnostic potential of 4 conventional and 15 novel, objectively determined, parameters in patients with early Age-related Macular Degeneration. Focal cone electroretinograms were recorded in 54 participants with early Age-related Macular Degeneration (72.9±8.2 years) and 54 healthy controls (69±7.7 years). Conventional a and b wave amplitudes and implicit times were measured and compared to novel parameters derived from both the 1st and 2nd derivatives and the frequency-domain power spectrum of the electroretinogram.Statistically significant differences between groups were shown for all conventional parameters, the majority of 1st and 2nd derivative parameters and the power spectrum at 25 and 30 Hz. Receiver operating characteristics showed that both conventional and 1st and 2nd derivative implicit times had provided the best diagnostic potential. A regression model showed a small improvement over any individual parameter investigated. The non-conventional parameters enhanced the objective evaluation of the focal electroretinogram, especially when the amplitude was low. Furthermore, the novel parameters described here allow the implicit time of the electroretinogram to be probed at points other than the peaks of the a and b waves. Consequently these novel analysis techniques could prove valuable in future electrophysiological investigation, detection and monitoring of Age-related Macular Degeneration

Development of polypoidal lesions in age-related macular degeneration

[Purpose]To determine the pre-treatment ocular factors significantly associated with the visual outcome 24 months after intravitreal bevacizumab (IVB) for myopic choroidal neovascularization (mCNV). [Methods]A total of 23 eyes of 23 patients with mCNV were treated with IVB followed by as needed therapy. The efficacy of IVB was evaluated by the best-corrected visual acuity (BCVA) at 24 months after the initial treatment. Forward stepwise multiple linear regression analyses were performed to evaluate the influence of pre-treatment factors on the BCVA and the improvement of the BCVA at 24 months. [Results]The mean pre-IVB BCVA was 0.74±0.30 logarithm of the minimum angle of resolution (logMAR) units, and it improved to 0.43±0.31 logMAR units after 1 month (P<0.001, paired t-test). The improvement was maintained at 24 months (0.46±0.40, P<0.005). The mean number of IVB performed during the 24 months was 1.35±0.71. Forward stepwise regression analysis showed that the pre-IVB CNV size (standardized β=0.52, P<0.01) and BCVA (standardized β=−0.44, P<0.05) significantly affected the visual acuity change after 24 months. The CNV size was the only factor that significantly affected the BCVA after 24 months (standardizedβ=0.56, P<0.01). [Conclusions] IVB with as needed therapy for mCNV led to a rapid and sustained visual improvement. Smaller CNV size was a significant prognostic factor that predicts better visual acuity. Patients with lower pre-treatment BCVA had better visual recovery than those with better pre-treatment BCVA, however, this may be due to a ceiling/floor effect