Subjective standard automated perimetry continues to be the method of choice for assessing visual field defects (VFDs). A more expedient, objective approach is now required, nevertheless. These conditions are satisfied by pupil perimetry (PP), which measures pupil responses to the start of bright stimuli to determine visual sensitivity. It was still being determined which PP technique finds VFDs the most precisely. For a study, researchers sought to compare the three PP approaches for gauging pupil response.
The inner 60 degrees of vision at 44 wedge-shaped spots were tested monocularly to compare unifocal (UPP), flicker (FPP), and multifocal PP (MPP). About 18 healthy adults (mean age and SD 23.7±3.0 years) had their visual field (VF) sensitivity tested while they were each subjected to quadrantanopia, a scotoma of a 20- or 10-degree diameter, and a scotoma of a 10-degree diameter for a total of three artificially simulated scotomas lasting about 4.5 minutes each.
The greatest pupil responses were elicited by stimuli that were totally visible on the screen, followed by those that were half visible, and finally, by those that were missing. However, MPP performed better for fully present vs. partially present trials than FPP did for present against absent trials (median d-prime = 6.26 ± 2.49, area under the curve [AUC] = 1.0 ± 0), and pupil responses in MPP demonstrated superior discriminative capacity for present versus absent trials (median d-prime = 1.19 ± 0.62, AUC = 0.80 ± 0.11).
They performed the first comprehensive analysis of three PP techniques. While MPP performed somewhat better with tiny (relative) scotomas, gaze-contingent FPP exhibited the highest discriminative power for large (absolute) scotomas.