One minute Multiple Pupillary Frequency Tagging test to assess visual field defects

Abstract

Pupillary responses to light offer a convenient and objective way to quickly assess the functional health of the anterior afferent visual pathways. We here present a proof of concept of an innovative one minute pupillary test consisting in 9 visual sub-regions simultaneously modulated in luminance at 9 different temporal frequencies. The spectral power of the sustained pupillary responses evoked by this display over 45 seconds of passive fixation distinguishes patients with retinal and optic nerve diseases from healthy participants with remarkable sensitivity and specificity, at both global and local scales. Reliable and fast, this test could ease patient care and allow screening for, and following-up, chronic ophthalmic diseases whose prevalence worryingly increases worldwide.

Computerized biofeedback to characterize Pupil Cycle Time (PCT) in neuropathies and retinopathies

“…We hypothesized than the PCT characteristics could be altered in both neuropathies and retinopathies, as the retinal circuits involved in pupillary responses are also altered (See e.g. 17 ). We also considered the possibility that in both neuropathies and retinopathies, the integration time of visual stimulation could be lengthened, which could be reflected in the lengthening of the PCT.…”

“…The session started with positioning the participants and adjusting the cameras of the eye-tracker. After 10 minutes of adaptation to the low ambient light of the testing room, during which a questionnaire was given to the participants, a 5 point eye calibration procedure was given before series of short (<1 minutes) tests, including PLR measures, RAPD assessment, as well as other tests, including the large-field and quadrant Multiple Pupillary Frequency Tagging tests (mPFT, see Ajasse et al, 2022). Overall, a session lasted about 2 hours.…”

“…ramping full-field stimuli 15 ), but the general outcome is that pupillary activity is perturbed in a number of ophthalmic diseases affecting the retina (hereditary retinitis pigmentosa, diabetic retinopathy…) or the optic nerve (glaucoma, non-glaucomatous optic neuropathies) 16 . Importantly, altered pupillary responses are correlated to structural deficits (RNFL, GCC) measured for instance with Optical Coherence Tomography (OCT) 15,17 . These reflexive physiological objective pupillary responses can be measured non-invasively with little expertise and resources in a short amount of time, dispending individuals to give a subjective, criterion dependent, response.…”

Effects of Stimulus Luminance, Stimulus Color and Intra-Stimulus Color Contrast on Visual Field Mapping in Neurologically Impaired Adults Using Flicker Pupil Perimetry

“…2,3,30,52 Other methods that utilize pupillary responses to assess visual sensitivity consist of unifocal [53][54][55] and multifocal 56,57 stimulus presentations or multiple frequency tagging. 58 Their attempts mainly focused on detecting glaucoma, a disease that asks for long-term monitoring to detect small decrements of function in the peripheral visual field. We suggest that pupil perimetry might be more suited to the screening of visual field defects (VFDs) caused by brain disease (eg cerebral infarction or tumor) which are more often larger and less prone to subtle changes.…”

Method to Quickly Map Multifocal Pupillary Response Fields (mPRF) Using Frequency Tagging

“…We further analyze the correlation of pupillary spectral power with structural data (Retinal Nerve Fiber Layer, RNFL). We end with a summary of clinical studies [ 31 , 32 ] performed with mPFT on several neuropathies and retinopathies that demonstrate that mPFT reflects the location of retinal damages specific to each pathology and provides excellent classification results, opening the way to routine use in clinical settings. We then discuss this method with regard to current functional evaluations, as well as some limitations and advantages of mPFT.…”