Night vision

About: Night vision is a research topic. Over the lifetime, 6004 publications have been published within this topic receiving 67372 citations.

Optics of the Eye

Abstract: This chapter shows how the human eye is a wonderful instrument and how it functions The chapter provides brief introduction of the diaphragm and the lens Kepler was the first who discovered that the image is formed on the retina He had also suggested that the inverted image appeared on the retina Mariotte had found the Mariotte spot or blind spot The concept of myopia and the Snellen notation are also explained The chapter talks about photoreceptors, visual pigments and the phosphorescent effect in the eyes of animals like cats This is created by the tapetum, an important structure of the eye that improves the night vision of terrestrial animals Further it describes compound eyes that are constituted of ommatidia and how these ommatidia help insects see polarized light and to know the direction of the sun although they cannot see the sun

Topography of Neurons in the Rod Pathway of Human Retina.

Abstract: Purpose The objective of this study was to map the distribution and density of the three major components of the classical scotopic "night vision" pathway (rods, rod bipolar, and AII amacrine cells) in postmortem human retinas. Methods Four postmortem donor eyes (male and female, aged 44-56 years) were used to cut vertical sections through the temporal horizontal meridian. The sections were processed for immunohistochemistry and imaged using high-resolution multichannel confocal microscopy. Rods, rod bipolar, and AII amacrine cells were counted along the temporal horizontal meridian. Two additional retinas were used for intracellular injections. Results Rod peak density is close to 150,000 cells/mm2 at 4 to 5 mm (15° to 20°) eccentricity, declining to below 70,000 cells/mm2 in peripheral retina. Rod bipolar density is lower but follows a similar distribution with peak density near 10,000 cells/mm2 between 2 and 4 mm (7° to 15°) eccentricity declining to below 4000 cells/mm2 in peripheral retina. The peak density of AII amacrine cells (near 4000 cells/mm2) is located close to the fovea, at 0.5- to 2 mm-eccentricity (2° to 7°) and declines to below 1000 cells/mm2 in the periphery. Thus, convergence between rods and AII cells increases from central to peripheral retina. Conclusions Comparison with human psychophysics and ganglion cell density indicates that the spatial resolution of scotopic vision is limited by the AII mosaic at eccentricities below 15° and by the midget ganglion cell mosaic at eccentricities above 15°.

Monocular mounting for four-tube panoramic night vision goggle having multi-function adjustment control

Abstract: There is disclosed a multi-channel panoramic night vision goggle (PNVG) system having two monocular subassemblies, each having a first channel and a second channel, each channel having an optical axis. A mounting structure, having a right and a left side, and having two angled mounting shoes may be used to mount the monocular subassemblies. The angled mounting shoes permit a single monocular subassembly to be attached to either side of the mounting structure, yet permit an optical axis of one of the first or second channels to be substantially coaxial with a user's optical axis and permits the other of the first and second channels to be at an angle not coaxial or parallel with the user's optical axis. In addition, a multi-function control may be provided to enable adjustment of the monocular subassemblies along one or more orientation axes.

Comparison of the Goldmann-Weekers dark adaptometer and LKC Technologies Scotopic Sensitivity tester-1.

Abstract: The standard for dark adaptation has long been the Goldmann-Weekers Dark Adaptometer™ (Haag-Streit). More recently, portable, relatively inexpensive LED-based dark adaptometers have become commercially available. These devices have potential use in areas with limited resources to screen for night-blindness, commonly caused worldwide by vitamin A deficiency. In order to determine the sensitivity to detecting changes in night vision, this study compared one such device, LKC Technologies Scotopic Sensitivity Tester-1™ (SST- 1) to the Goldmann-Weekers in patients with hereditary retinal degeneration and loss of rod function. Dark-adapted final thresholds and rod full-field ERG responses were obtained from 87 patients and 24 normal subjects. Linear regression analysis, discrepancy analysis, and receiver operator characteristic curves for both devices show that the SST-1 quantifies psychophysical rod function nearly as well as the Goldmann-Weekers, within some limitations. We conclude, therefore, that the SST-1 is a viable alternative to the Goldmann-Weekers for the screening of night-blinding retinal disorders.