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Chi D Luu, Galina Makeyeva, Emily Caruso, Elizabeth Baglin, Pyrawy Sharangan, Robyn H Guymer; Multifocal Electroretinogram Responses Following Subthreshold Nanosecond Laser Intervention In Age-Related Macular Degeneration.. Invest. Ophthalmol. Vis. Sci. 2019;60(9):1140.
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© ARVO (1962-2015); The Authors (2016-present)
Subthreshold nanosecond laser (SNL) treatment has recently been shown promise in certain phenotypes of intermediate age-related macular degeneration AMD (iAMD) as a potential treatment.The purpose of the study was to determine the longitudinal effect of SNL treatment on retinal function.
The LEAD trial was a 36-month, multicenter, randomized, sham-controlled trial in iAMD. Participants in the LEAD trial were assigned randomly to receive SNL treatment or sham treatment to the study eye at 6-monthly intervals. In this sub-study of retinal function, multifocal electroretinogram (mfERG) was performed on consenting participants at one site.Each subject had mfERG recorded at baseline and at 12, 24 and 36 month visits, using a VERIS system and DTL electrodes. The mfERG responses were grouped into three regions of central (R1, 0-4°), middle (R2, 4-12°) and outer ring (R3, 12-22°). The mfERG P1 response amplitude and implicit time of the first order kernel were compared between the groups over the follow-up period.
Twenty-seven subjects in the SNL treatment group and 24 subjects in the sham group completed 3 years of mfERG assessment. At baseline, the mean P1 response amplitudes of both the study eyes and the fellow eyes were similar between the groups at all rings. There was a decrease in P1 amplitude over 36 months follow-up observed in the sham treatment group (P < 0.05). A similar trend of P1 amplitude reduction was also observed in the SNL treatment group, but only for the first 24 months. At the 36-month visit, there was an improvement in the P1 amplitude in the SNL treatment group compared to the sham group detected at ring 1 (P = 0.005) and ring 2 (P = 0.007) but not at ring 3 (P = 0.070). A similar finding was also observed in the fellow eyes. There was an increase in P1 implicit time over the study period in both groups, but only at ring 1 (P = 0.010). However, there was no difference in P1 implicit time between the groups at any rings (P > 0.05).
SNL treatment appears to improve retinal function years after treatment commenced. Whether improvement in retinal function associated with lowered risk of progression from intermediate to late AMD requires further investigations. The effect of SNL treatment in the fellow eye has been shown previously, but the mechanism is unclear.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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