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Andre Messias, Katharina Messias, Rafael Arcieri, Vinicius Castro, Rubens Siqueira, Rodrigo Jorge; Chromatic Full-field Stimulus Threshold (FST) in Retinitis Pigmentosa - Relationships with electroretinography and visual field outcomes. Invest. Ophthalmol. Vis. Sci. 2013;54(15):5112.
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© ARVO (1962-2015); The Authors (2016-present)
To describe the relationships between chromatic full-field stimulus threshold (FST), electroretinography (ERG), and visual field (VF) outcomes in retinitis pigmentosa (RP) with concentric VF constriction and remaining central fixation.
Data from 23 patients with RP (n=46 eyes) was analyzed. Patients were submitted to measurement of best-corrected visual acuity (BCVA), 30-2-threshold static VF (OCTOPUS 900) to determine the mean deviation (MD), microperimetry (MAIA - CenterVue) for fixation stability (95 % bivariate contour ellipse area - BCEA), and the average macular sensitivity (AVS) assessment, full field, and multifocal ERG (ISCEV standard). FST was psychophysically determined before ERG recordings, after 25 minutes dark adaptation, using Espion E2 system with the ColorDome LED full-field stimulator (Diagnosys LLC, Lowell, MA), first using red (635 to 638 nm), then blue (465 to 470 nm), and then white (6500 K) stimulus, with 5 minutes inter-session interval.
Mean ± SE FST was white: -19.7 ± 1.1 dB, blue: -24.1 ± 1.4 dB, and red: -14.6 ± 0.5. White FST correlates better with blue (r=0.92; P<0.001) than with red (r=0.46; P=0.001), or blue with red (r=0.50; P=0.004). BCVA show week significant correlation with red FST (r=0.29; P=0.041), but not with blue (r=0.19; P=0.214) or white (r=0.22; P=0.142), while visual field MD showed moderate significant correlation with red FST (r=-0.60; P<0.001), but not with blue (r=-0.20; P=0.178) or white (r=-0.18; P=0.222), and AVS also correlates better with red FST (r=-0.70; P<0.001) than with blue (r=-0.40; P=0.006) or white (r=-0.41; P=0.005). Dark and light-adapted ERGs were not recordable in 40 (87%), and 15 (33%) eyes respectively. Considering the eyes with recordable cone response b-wave amplitude, a significant correlation was found for the 3 FST colors (P<0.001), with correlation coefficients slightly higher for red (-0.73) than for white (-0.69) and blue (-0.70).
Red FST correlates better than white or blue FST with retinal sensitivity measured with visual field tests, and strongly correlates with cone b-wave amplitude in RP patients. In addition, dark-adapted blue FST can be well determined in eyes without recordable rod ERG. Chromatic FST might add interesting information about visual function in RP.
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