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Chi D. Luu, Kate Brassington, Galina Makeyeva, Robyn H. Guymer; Bilateral Multifocal Electroretinogram Changes After Nanosecond Laser In Subjects With Early Age-related Macular Degeneration. Invest. Ophthalmol. Vis. Sci. 2012;53(14):6536.
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The Ellex 2RT nanosecond laser is being trialed as an intervention for early age-related macular degeneration (AMD) and we have previously reported bilateral clinical and psychophysical changes after unilateral laser treatment. In this study, we wished to determine the effect of Ellex 2RT on retinal function in both the treated and untreated eye using the multifocal electroretinogram (mfERG).
Twelve, single laser pulses of 3 nanosecond duration, 400µm diameter spot and 532nm wavelength, were placed in the outer macula of one eye (energy range of 0.15mJ to 0.45mJ) of 50 subjects with bilateral early AMD. The laser treatment was delivered via the new Ellex 2RT (Ellex Pty Ltd). Multifocal electroretinogram (mfERG) data were performed on 10 of these subjects (age ranged from 50 to 75 years). Each subject had mfERG recorded serially at baseline before receiving the 2RT and again at 3, 6 and 9 months post-treatment. All recordings were performed using a VERIS system and DTL electrodes. The mfERG P1 response amplitude and implicit time of the first order kernel before and after laser treatment were compared.
The mean P1 response amplitude and implicit time at baseline were 13.7 ± 9.4 nV/deg2 and 30.0 ± 1.7 msec, respectively. The P1 implicit time of the treated eyes was significantly increased at 3 months post-laser (34.0 ± 1.8 msec, p < 0.001) and remained significantly delayed at 6 (33.1 ± 1.7 msec, p < 0.001), and 9 (33.5 ± 1.7 msec, p < 0.001) months post-laser. There was a trend of P1 amplitude reduction over time in the treated eyes, however, the means P1 amplitude at 3 (14.1 ± 9.5 nV/deg2, p = 0.805), 6 (13.1 ± 7.8 nV/deg2, p = 0.594), and 9 (11.6 ± 6.6 nV/deg2, p = 0.077) months post-laser were not significantly different from the baseline value. Similar patterns of implicit time and amplitude changes were observed in the untreated fellow eyes.
Retinal function, as measured by the mfERG is altered in both the treated and untreated fellow eye following nanosecond laser treatment in eyes with early AMD. These bilateral changes appeared to be long lasting over many months. The cause and implications of these changes is unknown and further investigations are required.
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