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For a pixel pair (one white and one black pixel) this gives a pixel density of 128 pixels per degree (PPD). 6/6 vision is defined as the ability to resolve two points of light separated by a visual angle of one minute of arc, corresponding to 60 PPD, or about 290–350 pixels per inch for a display on a device held 250 to 300 mm from the eye. [24]
The quality of vision expected from a retinal implant is largely based on the maximum spatial resolution of the implant. Current prototypes of retinal implants are capable of providing low resolution, pixelated images. "State-of-the-art" retinal implants incorporate 60-100 channels, sufficient for basic object discrimination and recognition tasks.
Each human retina has approximately 6 million cones and 120 million rods. [8] At the "center" of the retina (the point directly behind the lens) lies the fovea (or fovea centralis), which contains only cone cells; and is the region capable of producing the highest visual acuity or highest resolution. Across the rest of the retina, rods and ...
Optical resolution. Optical resolution describes the ability of an imaging system to resolve detail, in the object that is being imaged. An imaging system may have many individual components, including one or more lenses, and/or recording and display components.
The 1931 CIE photopic luminosity function. The horizontal axis is wavelength in nm. Photopic vision is the vision of the eye under well-lit conditions (luminance levels from 10 to 10 8 cd/m 2). In humans and many other animals, photopic vision allows color perception, mediated by cone cells, and a significantly higher visual acuity and temporal ...
Uranus, when discovered in 1781, was the first planet discovered using technology (a telescope) rather than being spotted by the naked eye. Theoretically, in a typical dark sky, the dark adapted human eye would see the about 5,600 stars brighter than +6 m [6] while in perfect dark sky conditions about 45,000 stars brighter than +8 m might be ...
Specialty. Ophthalmology. [edit on Wikidata] Clear lens extraction, also known as refractive lensectomy, custom lens replacement or refractive lens exchange is a surgical procedure in which clear lens of the human eye is removed. Unlike cataract surgery, where cloudy lens is removed to treat cataract, clear lens extraction is done to surgically ...
Argus retinal prosthesis, also known as a bionic eye, is an electronic retinal implant manufactured by the American company Second Sight Medical Products. It is used as a visual prosthesis to improve the vision of people with severe cases of retinitis pigmentosa. The Argus II version of the system was approved for marketing in the European ...