V.F. Pyatin - Dr.Sc.(Med.), Professor, Head of Department of Normal Physiology, Samara State Medical University, Russia. E-mail: pyatin_vf@list.ru
M.S. Sergeeva - Ph.D. (Biol.), Assistant Professor, Department of Normal Physiology, Samara State Medical University, Russia. E-mail: marsergr@yandex.ru
I.V. Shirolapov - Ph.D. (Med.), Senior Lecturer, Department of Normal Physiology, Samara State Medical University, Russia. E-mail: ishirolapov@mail.ru

It is generally accepted that the blink reflex protects the eyes from potential damage that may be caused by external factors, carried out spontaneously from an average rate of 10-15 per minute, helping to moisturize the cornea and conjunctiva, and is automatic and were unaware of the process [1]. Each blink lasts on average from 150 to 400 ms during which the human visual patterns disappear, and roughly 100 times the luminous flux is reduced to the retina. Simultaneously decreases the activity and parietal areas of the prefrontal cortex [2], which indicates the general oppression awareness. Opening intrinsically photosensitive retinal ganglion cells (ipRGCs) [1] suggests that the main function of nervous mechanism is the regulation of blinking light and photosensitive retinal ganglion cells monosynaptically associated primarily with neurons suprachiasmatic nuclei of the hypothalamus, the center of the human circadian system [3]. Therefore, according to our hypothesis, human blink rate caused by the degree of illumination of the retina and nervous regulating mechanism controls blinking related physiological processes, including ipRGCs light adaptation. Testing the hypothesis on the relationship of retinal illumination and blink was the goal of our work. The study involved 25 volunteers aged 19,16 ± 0,17 years, which recorded the frequency of blinking EMG m.orbicularis oculi under different light. Time measurement at each stage and the time interval between the stages averaged 1 min. Lighting parameters (lux) and luminance (cd/m2) light was measured with an instrument combined TKA -PKM (02). Maximum blink rate (41,4 ± 5,60 min-1) was recorded in the subjects under sunlight (30520,0 ± 1310,9 lux, 4832,4 ± 149,08 cd/m2) (r = 0,520; p = 0,080). Daylight subjects to "back to sunlight» (305,76 ± 12,619 lux, 178,56 ± 6,813 cd/m2) reduced the incidence of blinking an average of 13,28 ± 2,54 min-1 (r = 0,487; p = 0,016). When you gaze at the computer screen with brightness 532,5 ± 33,6 lux brightness and 98,72 ± 5,25 cd/m2 blink rate in subjects was 15,6 ± 2,39 min-1 (r = 0,570; p = 0,030). Our pilot study allow to make conclusion that the frequency blink man correlated with the levels of ambient light. Conventional wisdom that the main function of blinking is hydration of the cornea and conjunctiva, is not confirmed by our studies (unpublished data) on volunteers with contact lenses. Available data indicates that wearing contact lenses is described above, the relationship between the frequency blink and external illumination. On this basis we for the first time expressed the hypothesis about the leading role of blinking in the regulation of light exposure to the retina, light adaptation of the ipRGCs, circadian rhythms of retinal cells and circadian biorhythms of an organism that requires the future fundamental research.