The photoreceptors in the retina are equipped with two types of sensory cells, rods, and cones.
RETINA ANATOMY DIAGRAM FULL
Most people see the world in full colour, and they have their retina to thank for it. Our brain then processes the received information and shows us the image – our eyesight. The retina forwards the received image through the optic nerve to the brain. The lens then works with the cornea to focus the light correctly, as it passes through the vitreous humour to the retina. After the cornea, the light goes through the pupil (the opening of the iris), controlling how much light is let through. The first step to eyesight is when light passes the thin tear film and through the cornea, where the eye first focuses. If any of these parts are not working properly, due to eye conditions, diseases or injuries, our vision is affected. The various structures mentioned are all necessary to work together for us to perceive sight. These impulses are transmitted through millions of fibres in the optical nerve. The optic nerve sends signals and impulses to the visual cortex of the brain, which is responsible for our vision.
It sits at the very back of the eye and connects to the brain. The optic nerve is the biggest nerve of the eye. This tissue works as a receptor for light. Like a film camera, the retina processes light through photoreceptor cells to detect colour and different lighting, which helps the optic nerve to send impulses to the brain, turning into images. The retina is a light-sensitive tissue, lining the back of the eyes. The vitreous humour has a vital role in ensuring the eye holds its spherical shape, thereby protecting your eye from injury and trauma. It takes up two thirds of the eye’s structure and attaches to the retina. The vitreous humour is a gelatinous substance that lies behind the crystalline lens in the back of the eye. It contains a combination of water, collagen, and proteins. As we age, the lens loses its elasticity, which leads to the inevitable ageing condition presbyopia. When we are born, the lens is flexible and reshapes to allow the eyes to focus on varying distances. The crystalline lens is the transparent tissue that sits directly behind the pupil.
The iris adjusts to different light settings, allowing the right amount of light through the pupil. It dilates in darker light conditions and constricts in brightly lit environments or when looking at close objects. It sits behind the cornea but in front of the lens and is circled around the opening known as pupil.
The iris is the brown, blue or green coloured part of the eye. As it is one of the first areas the light reaches when it enters the eyes, it is responsible for most of our eyesight. If the cornea is too flat, too curved or misshapen, it causes refractive errors, such as short or long-sightedness and astigmatism.
The main function of the cornea is vision. The cornea is the transparent dome shape that is the outer cover in front of the iris and pupil, behind a thin tear film. The sclera surrounds most of the eye, front and back, and offers protection to the eye whilst conserving its structure and protecting it from injury. The sclera is the white part of the eye, a fibrous layer consisting of collagen that is continuous with the cornea. The human eye is a sensory organ, sitting in the socket called the orbit, surrounded by skin, muscle and a strong layer of tissue. There are many parts of the eye that work together to make it work and, if looked after properly, protect it from some sight-threatening diseases and injuries.
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