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The full-field stimulus test (FST) is a psychophysical technique designed for the measurement of visual function in low vision. The method involves the use of a ganzfeld stimulator, as used in routine full-field electroretinography, to deliver full-field flashes of light. This guideline was developed jointly by the International Society for Clinical Electrophysiology of Vision (ISCEV) and Imaging and Perimetry Society (IPS) in order to provide technical information, promote consistency of testing and reporting, and encourage convergence of methods for FST. It is intended to aid practitioners and guide the formulation of FST protocols, with a view to future standardisation., (© 2024. The Author(s).)

Purpose: To compare conventional structural and functional measures of glaucomatous damage with a new functional measure-contrast sensitivity perimetry (CSP-2)., Methods: One eye each was tested for 51 patients with glaucoma and 62 age-similar control subjects using CSP-2, size III 24-2 conventional automated perimetry (CAP), 24-2 frequency-doubling perimetry (FDP), and retinal nerve fiber layer (RNFL) thickness. For superior temporal (ST) and inferior temporal (IT) optic disc sectors, defect depth was computed as amount below mean normal, in log units. Bland-Altman analysis was used to assess agreement on defect depth, using limits of agreement and three indices: intercept, slope, and mean difference. A criterion of p < 0.0014 for significance used Bonferroni correction., Results: Contrast sensitivity perimetry-2 and FDP were in agreement for both sectors. Normal variability was lower for CSP-2 than for CAP and FDP (F > 1.69, p < 0.02), and Bland-Altman limits of agreement for patient data were consistent with variability of control subjects (mean difference, -0.01 log units; SD, 0.11 log units). Intercepts for IT indicated that CSP-2 and FDP were below mean normal when CAP was at mean normal (t > 4, p < 0.0005). Slopes indicated that, as sector damage became more severe, CAP defects for IT and ST deepened more rapidly than CSP-2 defects (t > 4.3, p < 0.0005) and RNFL defects for ST deepened more slowly than for CSP, FDP, and CAP. Mean differences indicated that FDP defects for ST and IT were on average deeper than RNFL defects, as were CSP-2 defects for ST (t > 4.9, p < 0.0001)., Conclusions: Contrast sensitivity perimetry-2 and FDP defects were deeper than CAP defects in optic disc sectors with mild damage and revealed greater residual function in sectors with severe damage. The discordance between different measures of glaucomatous damage can be accounted for by variability in people free of disease.

Purpose: To develop perimetric stimuli that are resistant to the effects of peripheral defocus., Methods: One eye each was tested on subjects free of eye disease. Experiment 1 assessed spatial frequency, testing 12 subjects at eccentricities from 2 to 7 degrees using blur levels from 0 to 3 diopters (D) for two (Gabor) stimuli (spatial SD, 0.5 degrees; spatial frequencies, 0.5 and 1.0 cycles per degree [cpd]). Experiment 2 assessed stimulus size, testing 12 subjects at eccentricities from 4 to 7 degrees using blur levels 0 to 6 D for two Gaussians with SD of 0.5 and 0.25 degrees and a 0.5-cpd Gabor with SD of 0.5 degrees. Experiment 3 tested 13 subjects at eccentricities from fixation to 27 degrees using blur levels 0 to 6 D for Gabor stimuli at 56 locations; the spatial frequency ranged from 0.14 to 0.50 cpd with location, and SD was scaled accordingly., Results: In experiment 1, blur by 3 D caused a small decline in log contrast sensitivity for the 0.5-cpd stimulus (mean ± SE, 0.09 ± 0.08 log units) and a larger (t = 7.7, p < 0.0001) decline for the 1.0-cpd stimulus (0.37 ± 0.13 log units). In experiment 2, blur by 6 D caused minimal decline for the larger Gaussian, by 0.17 ± 0.16 log units, and larger (t > 4.5, p < 0.001) declines for the smaller Gaussian (0.33 ± 0.16 log units) and the Gabor (0.36 ± 0.18 log units). In experiment 3, blur by 6 D caused declines by 0.27 ± 0.05 log units for eccentricities from 0 to 10 degrees, by 0.20 ± 0.04 log units for eccentricities from 10 to 20 degrees, and 0.13 ± 0.03 log units for eccentricities from 20 to 27 degrees., Conclusions: Experiments 1 and 2 allowed us to design stimuli for experiment 3 that were resistant to effects of peripheral defocus.

Purpose: To design a contrast sensitivity perimetry (CSP) protocol that decreases variability in glaucomatous defects while maintaining good sensitivity to glaucomatous loss., Methods: Twenty patients with glaucoma and 20 control subjects were tested with a CSP protocol implemented on a monitor-based testing station. In the protocol 26 locations were tested over the central visual field with Gabor patches with a peak spatial frequency of 0.4 cyc/deg and a two-dimensional spatial Gaussian envelope, with most of the energy concentrated within a 4 degrees circular region. Threshold was estimated by a staircase method: Patients and 10 age-similar control subjects were also tested on conventional automated perimetry (CAP), with the 24-2 pattern with the SITA Standard testing strategy. The neuroretinal rim area of the patients was measured with a retinal tomograph (Retina Tomograph II [HRT]; Heidelberg Engineering, Heidelberg, Germany). A Bland-Altman analysis of agreement was used to assess test-retest variability, compare depth of defect shown by the two perimetric tests, and investigate the relations between contrast sensitivity and neuroretinal rim area., Results: Variability showed less dependence on defect depth for CSP than for CAP (z = 9.3, P < 0.001). Defect depth was similar for CAP and CSP when averaged by quadrant (r = 0.26, P > 0.13). The relation between defect depth and rim area was more consistent with CSP than with CAP (z = 9, P < 0.001)., Conclusions: The implementation of CSP was successful in reducing test-retest variability in glaucomatous defects. CSP was in general agreement with CAP in terms of depth of defect and was in better agreement than CAP with HRT-determined rim area.

Purposes: The purposes of this study are to compare macular perimetric sensitivities for conventional size III, frequency-doubling, and Gabor stimuli in terms of Weber contrast and to provide a theoretical interpretation of the results., Methods: Twenty-two patients with glaucoma performed four perimetric tests: a conventional Swedish Interactive Threshold Algorithm (SITA) 10-2 test with Goldmann size III stimuli, two frequency-doubling tests (FDT 10-2, FDT Macula) with counterphase-modulated grating stimuli, and a laboratory-designed test with Gabor stimuli. Perimetric sensitivities were converted to the reciprocal of Weber contrast and sensitivities from different tests were compared using the Bland-Altman method. Effects of ganglion cell loss on perimetric sensitivities were then simulated with a two-stage neural model., Results: The average perimetric loss was similar for all stimuli until advanced stages of ganglion cell loss, in which perimetric loss tended to be greater for size III stimuli than for frequency-doubling and Gabor stimuli. Comparison of the experimental data and model simulation suggests that, in the macula, linear relations between ganglion cell loss and perimetric sensitivity loss hold for all three stimuli., Conclusions: Linear relations between perimetric loss and ganglion cell loss for all three stimuli can account for the similarity in perimetric loss until advanced stages. The results do not support the hypothesis that redundancy for frequency-doubling stimuli is lower than redundancy for size III stimuli.

Purpose: To measure and quantify effects of variation in retinal illuminance on frequency doubling technology (FDT) perimetry., Methods: A Zeiss-Humphrey/Welch Allyn FDT perimeter was used with the threshold N-30 strategy. Study 1, quantifying adaptation: 11 eyes of 11 subjects (24-46 years old) were tested with natural pupils, and then retested after stable pupillary dilation with neutral density filters of 0.0, 0.6, 1.2, and 1.6 log unit in front of the subject's eye. Study 2, predicting effect of reduced illuminance: 17 eyes of 17 subjects (26-61 years old) were tested with natural pupils, and then retested after stable pupillary miosis (assessed with an infrared camera). A quantitative adaptation model was fit to results of Study 1; the mean adaptation parameter was used to predict change in Study 2., Results: Study 1: Mean defect (MD) decreased by 10 dB over a 1.6 log unit range of retinal illuminances; model fits for all subjects had r2> 95%. Study 2: Change in MD (DeltaMD) ranged from -7.3 dB to +0.8 dB. The mean adaptation parameter from Study 1 accounted for 69% of the variance in DeltaMD (P <0.0005), and accuracy of the model was independent of the magnitude of DeltaMD (r2< 1%, P >0.75)., Conclusions: The results confirmed previous findings that FDT perimetry can be dramatically affected by variations in retinal illuminance. Application of a quantitative adaptation model provided guidelines for estimating effects of pupil diameter and lens density on FDT perimetry.