Post-illumination pupil response after blue light: Reliability of optimized melanopsin-based phototransduction assessment.

摘要: Melanopsin-containing retinal ganglion cells have recently been shown highly relevant to the non-image forming effects of light, through their direct projections on brain circuits that regulate alertness, mood and circadian rhythms. A quantitative assessment functionality melanopsin-signaling pathway could be in order mechanistically understand individual differences light these regulatory systems. We here propose validate a reliable quantification melanopsin-dependent Post-Illumination Pupil Response (PIPR) after blue evaluated its sensitivity dark adaptation, time day, body posture, exposure history. diameter left eye was continuously measured during series exposures right eye, which pupil dilated using tropicamide 0.5%. The paradigm consisted following five consecutive blocks minutes: baseline dark; monochromatic red (peak wavelength: 630 nm, luminance: 375 cd/m(2)) maximize effect subsequent light; 470 cd/m(2)); post-blue dark. PIPR quantified as difference between (PIPR-mm). In addition, relative calculated by dividing (PIPR-%). total 54 assessments were obtained 25 healthy young adults (10 males, mean age ± SD: 26.9 4.0 yr). From repeated measurements two days 15 participants (6 27.8 4.3 yrs) test-retest reliability both outcome parameters calculated. presence considerable between-subject differences, had very high reliability: Cronbach's α > 0.90 Intraclass Correlation Coefficient 0.85. 12 26.5 3.6 yr) we examined potential confounding day (morning vs. afternoon), posture (upright supine position), 24-h environmental history assessment. Mixed regression models used analyze possible confounders. position caused larger PIPR-mm (β = 0.29 mm, SE 0.10, p 0.01) PIPR-% 4.34%, 1.69, 0.02), due an increase diameter; this finding is relevance for studies requiring functional Magnetic Resonance Imaging, constant routine protocols, bed-ridden patients. There no conclusion, presented method provides robust allow melanopsin-based phototransduction interventions.