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G. Dagnelie, R. A. Schuchard, J. Kotowski, A. K. Kiser, J. S. Pollack, K. Packo, A. Chow, ASR Study Group; Two-Year Central Visual Field Follow-Up in the ASR® Device Feasibility Trial. Invest. Ophthalmol. Vis. Sci. 2008;49(13):2187.
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To evaluate effects of the ASR® device on visual function over a two-year time span, with emphasis on Humphrey visual field outcomes. We have previously noted apparent neurotrophic benefits near the border of the central field and in peripheral islands assessed with Goldmann perimetry.
Twenty patients were enrolled at three participating clinical centers, and underwent extensive pre-op testing prior to monocular implantation of the ASR® device. Two Humphrey 30-2 field tests with size V targets were administered to each eye on each of three pre-op and 2-4 monthly post-op visits, with single fields on further visits, covering a time period from -1 to +24 months relative to the implant date. Number of seeing points in each field map and cumulative sensitivity values (CSV), obtained by summing dB sensitivities across all seeing points, were calculated in implant and fellow eyes.
CSV pre-op test re-test variability (SE) based on 6 field maps ranged from 4% to 80% and was used to establish a 95% confidence interval (CICSV) for post-op CSV evaluation. While pre-op log CSV correlated significantly with logMAR VA (p<.02), CICSV did not correlate with VA, refuting the notion that high CSV variability could be caused by poor fixation. Counting the number of post-op CSVs significantly exceeding CICSV in either direction, we find that implanted eyes do not fare better than control eyes beyond an initial 6 month interval: Decreased/unchanged/increased CSVs were found in 5 / 8 / 7 implanted, and 8 / 8 / 4 control eyes. Limiting the analysis to pseudophakes reduced these numbers to 4 / 3 / 1 in both implanted and control eyes. We previously reported that cataract incidence is common in phakic ASR® recipients, and this may lead to decreased sensitivity in the static VF.
We are continuing more detailed analyses (rings, quadrants) and will present results at the meeting. Central retinal function as assessed by the Humphrey 30-2 may not be a sensitive measure of neurotrophic ASR® benefits.
Clinical Trial: :
FDA: PDC - 0048
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