Definition of retina - What it is, Meaning and Concept

The retina is a membrane located inside the eye that is responsible for receiving the images and, through the optic nerve, sending them to the Brain: Composed of different cell layers, the retina is a kind of tissue that is sensitive to luminosity and that generates various processes until it reaches the transmission of a nerve impulse to the brain.

The photoreceptor cells (they get that name because they are sensitive to the light ) are the canes and the cones .It is estimated that, in the human being, the retina houses more than 126 million of these cells, mostly canes.The latter, precisely, come into operation when there is low luminosity and provide a vision in black and white.The cones, on the other hand, act in good light conditions and allow the development of color vision.

The outer layer of l the retina is called pigmentary epithelium .Then other layers appear until it reaches the so-called internal limiting layer , which divides the retina from the vitreous humor (liquid that is between the retina and the lens).

The retina may be affected by various problems that reduce the ability of eyesight. Hypertensive retinopathy causes a retinal deformation due to high blood pressure, while diabetic retinopathy is a damage caused by diabetes in the blood vessels that are responsible for irrigating the membrane.

The retinitis (an inflammation of the retina), the age-related macular degeneration (a deterioration in the central layer of the retina, called the macula) and the retinal detachment (the separation of the epithelial membrane to which it must adhere) are other disorders that the retina may suffer.

Retinal detachment usually occurs when it undergoes a perforation or a tear, which leads to the filtration of liquids from the eye .The aspect that usually has in this case, which is called posterior vitreous detachment , can be compared with that of an air bubble between a sheet of paper and a piece of adhesive tape.Other possible causes are very severe myopia or trauma, and the chances increase if they exist family history.

Regarding the symptoms of retinal detachment, we can point out the following: vision poorly defined; spots on the image; flashes of light, mainly in peripheral vision; inability to capture a complete image (partial blindness).

The name Retina Display (or Retina Display ) refers to a trademark belonging to the North American company Apple , used to identify a series of screens that are characterized by an especially high pixel density .

According to Apple, thanks to this technology you get a larger amount of pixels than the human eye's retina is able to perceive, although many specialists have opposed this statement, considering it a mere marketing instrument.

Among the companies responsible for developing and manufacturing the screens retina are Sharp, Samsung, Japan Display and LG .The technology on which they are based is In-plan switching (with its acronym IPS ), created by Hitachi in 1996 to improve the viewing angles and color quality on Twisted Nematic ( TN ) monitors, which, on the other hand, offer optimal response time.

The density of pixels on the retina display is 326 per inch , and Apple relied on this number to maintain that it exceeded our retina's capacity, noting that does not exceed 320 ; In other words, on a monitor of these characteristics, we are not able to distinguish one pixel from another, so that the sharpness is theoretically insurmountable (or excessive).