The Extended Maxwellian View (BIGMAX): A high-intensity, high-saturation color display for clinical diagnosis and vision research

Beer, R. Dirk; MacLeod, Donald I. A.; Miller, Timothy P.

doi:10.3758/bf03192722

Cited by 14 publications

(9 citation statements)

References 6 publications

(6 reference statements)

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“…The PIPR was measured using a custom-designed Maxwellian view pupillometer [2,4,21] which comprised five primary lights generated using narrowband LED sources (Fig 1) imaged in the pupil plane of the left eye via two Fresnel lenses (100 mm diameter, 127 mm and 70 mm focal lengths; Edmund Optics, Singapore) and a 5° light shaping diffuser (Physical Optics Corp., Torrance, CA, USA) to provide a 41° diameter light stimulus (retinal image diameter: 17.9 mm). The consensual PIPR of the fellow right eye was recorded under infrared LED illumination (λ max = 851 nm) with a PixeLINK camera (IEEE -1 394, PL-B741 FireWire; 640 x 480 pixels; 60 frames/s; PIXELINK, Ottawa, ON, Canada) through a telecentric lens (2/3-inch 55 mm and 2 X extender C-Mount; Computar, Singapore).…”

Section: Methodsmentioning

confidence: 99%

Rhodopsin and Melanopsin Contributions to the Early Redilation Phase of the Post-Illumination Pupil Response (PIPR)

2016

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Melanopsin expressing intrinsically photosensitive Retinal Ganglion Cells (ipRGCs) entirely control the post-illumination pupil response (PIPR) from 6 s post-stimulus to the plateau during redilation after light offset. However, the photoreceptor contributions to the early redilation phase of the PIPR (< 6 s post-stimulus) have not been reported. Here, we evaluated the photoreceptor contributions to the early phase PIPR (0.6 s to 5.0 s) by measuring the spectral sensitivity of the criterion PIPR amplitude in response to 1 s light pulses at five narrowband stimulus wavelengths (409, 464, 508, 531 and 592 nm). The retinal irradiance producing a criterion PIPR was normalised to the peak and fitted by either a single photopigment nomogram or the combined melanopsin and rhodopsin spectral nomograms with the +L+M cone photopic luminous efficiency (Vλ) function. We show that the PIPR spectral sensitivity at times ≥ 1.7 s after light offset is best described by the melanopsin nomogram. At times < 1.7 s, the peak PIPR sensitivity shifts to longer wavelengths (range: 482 to 498 nm) and is best described by the combined photoreceptor nomogram, with major contributions from melanopsin and rhodopsin. This first report of melanopsin and rhodopsin contributions to the early phase PIPR is in line with the electrophysiological findings of ipRGC and rod signalling after the cessation of light stimuli and provides a cut-off time for isolating photoreceptor specific function in healthy and diseased eyes.

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Section: Methodsmentioning

confidence: 99%

Rhodopsin and Melanopsin Contributions to the Early Redilation Phase of the Post-Illumination Pupil Response (PIPR)

2016

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“…Light stimuli were generated using a custom-built optical system with the design based on an extended Maxwellian view optical system (Beer, MacLeod, & Miller, 2005; Kankipati, Girkin, & Gamlin, 2010). Light generated by 5 mm LEDs (blue appearing short wavelength: λ max = 464 nm, 19 nm half-bandwidth; red appearing long wavelength: λ max = 638 nm, 15 nm half-bandwidth) was imaged in the plane of the right pupil via two Fresnel lenses (100 mm diameter, 127 mm and 70 mm focal lengths; Edmund Optics, Singapore) and a 5° light shaping diffuser (Physical Optics Corp., California USA).…”

Section: Methodsmentioning

confidence: 99%

Temporal characteristics of melanopsin inputs to the human pupil light reflex

et al. 2015

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Rods, cones and melanopsin containing intrinsically photosensitive Retinal Ganglion Cells (ipRGCs) operate in concert to regulate pupil diameter. The temporal properties of intrinsic ipRGC signalling are distinct to those of rods and cones, including longer latencies and sustained signalling after light offset. We examined whether the melanopsin mediated post-illumination pupil response (PIPR) and pupil constriction were dependent upon the inter-stimulus interval (ISI) between successive light pulses and the temporal frequency of sinusoidal light stimuli. Melanopsin excitation was altered by variation of stimulus wavelength (464 nm and 638 nm lights) and irradiance (11.4 and 15.2 log photons.cm−2.s−1). We found that 6s PIPR amplitude was independent of ISI and temporal frequency for all melanopsin excitation levels, indicating complete summation. In contrast to the PIPR, the maximum pupil constriction increased with increasing ISI with high and low melanopsin excitation, but time to minimum diameter was slower with high melanopsin excitation only. This melanopsin response to briefly presented pulses (16 and 100 ms) slows the temporal response of the maximum pupil constriction. We also demonstrate that high melanopsin excitation attenuates the phasic peak-trough pupil amplitude compared to conditions with low melanopsin excitation, indicating an interaction between inner and outer retinal inputs to the pupil light reflex. We infer that outer retina summation is important for rapidly controlling pupil diameter in response to short timescale fluctuations in illumination and may occur at two potential sites, one that is presynaptic to extrinsic photoreceptor input to ipRGCs, or another within the pupil control pathway if ipRGCs have differential temporal tuning to extrinsic and intrinsic signalling.

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“…16 The two lenses were mounted within an enclosure. At one end of the enclosure the blue (470 nm) and red (623 nm) LEDs (25 nm, full width at half maximum; Optek Technology, Inc., Carrollton, TX) were positioned at the focal point of the first Fresnel lens with a beam splitter (50 ϫ 50 ϫ 1 mm; Edmund Optics; Fig.…”

Section: Testing Apparatusmentioning

confidence: 99%