The definition of Retina
The retina is a tissue (tissue) is very thin wall that separates the inside of the back of the eye. When we look around, the light from objects that let's look into the eyes. The light from the image focused on the retina by the cornea and lens. This light striking the retina causes a complex biochemical changes within layers of the retina and this in turn stimulates an electrical response in the other layers of the retina. Nerve ending in the retina sends signals to the brain via this optic nerve. In typical areas of the brain, electrical energy is processed to allow us to see and understand what we are seeing. The retina has been compared with the film from the camera. However, the film, once used, has a permanent image thereon. The retina is continuously renews itself chemically and electrically, allowing us to see millions of different pictures every day without the buildup of the images.
Retinal size about the size of a postage stamp. He consists of a central area called the macula and retinal circumference (peripheral retina) is much larger. The light receptor cells in the retina there are two types, called rods and cones. Rods allow us to see in the dark. Cones give us sharp eyesight. Peripheral retina allows us to see objects on both sides (peripheral vision) and, therefore, provides the vision necessary for a person to move safely. However, because this part of the retina contains a lesser concentration of cones, it does not allow for the perception of visual detail. Greater concentration of rods provides a better vision in dark conditions.
In contrast, the macula is a smaller, central area of the retina that contains a high concentration of cones. Therefore, it allows clear central vision to see the fine details for activities like reading or threading a needle. Macula is very sensitive to changes in circulation especially that occurs with aging, such as reduced blood flow. The retina contains a network of branching arteries, which supply blood carrying oxygen and nutrients necessary to the retina, and the veins that accompany him, which then carry the blood along with waste products of metabolism of the retina.
Definition of Retinal Detachment
A retinal detachment is a separation of the retina from its underlying tissue within the eye. Most retinal detachments are a result of cracking the retina (retinal break), holes, or tears. Retinal breaks can occur when the vitreous gel pulls loose or separates from its attachment to the retina, usually in the peripheral parts of the retina. The vitreous is a (gel) that fills the clear 2 / 3 inside the eye and occupy the space in front of the retina. When the vitreous gel pulls loose, he sometimes uses the pull on the retina, and if the retina is weak, the retina will tear. Most of the cracks are not a result of retinal injury. Retinal tears are sometimes accompanied by bleeding if retinal blood vessels involved in this tear.
Once a retinal tear, fluid from the vitreous gel can pass through the tears and gathered behind the retina. Buildup of fluid behind the retina is that separates (detaches) the retina from the back of the eye. As more liquid vitreous collects behind the retina, an extension of retinal detachment (retinal detachment) may progress and involve the entire retina, leading to a total release of the retina. A retinal detachment almost always affects only one eye. The second eye, however, must be checked thoroughly for any signs of the factors that influence that could lead to the release in the future.
