Butterfly eyes are random mosaics built of three ommatidia types, each with a different set of photoreceptors and pigments. What defines the combined features in each ommatidium? A new study has solved the puzzle.

Animals with front facing eyes benefit from a substantial overlap in the visual fields of each eye, and devote specialized brain processes to using the horizontal spatial disparities produced as a result of viewing the same object with two laterally placed eyes, to derived depth or 3-D stereo information. This provides the advantage to break the camouflage of objects in front of similarly textu...

The dual retina of humans and most vertebrates consists of multiple types of cone for colour vision in bright light and one single type of rod, leaving these animals colour-blind at night. Instead of comparing the signals from different spectral types of photoreceptors, they use one highly sensitive receptor, thus improving the signal-to-noise ratio. However, nocturnal moths and geckos can disc...

A follow-up study of colour vision in two patients with gyrate atrophy was performed. Gyrate atrophy was diagnosed in the first patient at the age of 17 years. Her colour vision was first tested at the age of 25 years; at the follow-up examination 7 years later, she correctly interpreted the Standard Pseudoisochromatic Plates part 2, however, with one mistake due to lens opacity. In the Farnswo...

Wavelength discrimination in goldfish was measured behaviourally. Both acute application of ethambutol injected into the eye and chronic application by feeding the animals daily 25 mg ethambutol for 1 month had the same effect on wavelength discrimination in the range of 560-640 nm. This means that: (1) electrophysiological experiments, in which drug application is primarily acute, reflect the ...

Background/Aims. To evaluate the impact of back-illuminated and nonilluminated electronic reading devices on reading speed and comfort in patients with decreased vision. Methods. A prospective study involving a convenience sample of 167 patients at a single retina practice from January 2011 to December 2012. Participants were asked to read five different excerpts on five different media in a ra...

R Vision therapy, also known as vision training, is a term used to define highly specific, sequential, sensory-motorperceptual stimulation paradigms and regimens that are used to improve vision skills, such as eye movement control and eye coordination.1 This training procedure can be performed in both home and office settings, but always under the professional supervision of an optometrist or a...

When rivalrous stimuli are presented intermittently, perception stabilises. This indicates the operation of perceptual memory across interruptions in stimulation. Here we show that a percept under non-rivalrous and rivalrous conditions has qualitatively different effects on subsequent rivalrous vision. When an image is perceived under rivalrous viewing, that image is more likely to be perceived...

In this paper, we introduce a novel surveillance system based on thermal catadioptric omnidirectional (TCO) vision. The conventional contour-based methods are difficult to be applied to the TCO sensor for detection or tracking purposes due to the distortion of TCO vision. To solve this problem, we propose a contour coding based rotating adaptive model (RAM) that can extract the contour feature ...

The congenital color vision deficient (CVD) generally demonstrates difficulties in color naming tasks. In our study we investigated color naming properties and uncertainties of a relatively large group of red-green CVDs using quasi monochromatic stimuli and seven basic color terms. The results show a large variability in color naming for the CVD when contrasted to normal color vision and simila...