Retina has rods (cells that help you see in low-light conditions) and cones (cells that detect colors). Your retina takes light the eyes are receiving and converts it to nerve signals so that your brain can make sense of what your eyes are seeing. Cells in your retina absorb and convert light to electrochemical impulses that are transmitted down your optic nerve, then into your brain.
Light hits the retina, the rear part of your eye, made up of a few different types of cells. When light hits the retina, tiny cells, rods, and cones, pick up signals from the light and turn them into electrochemical impulses in neurons. Light rays then travel through the lens, sharpening them on their way to the retina, the thin tissue layer behind the eyes containing the tiny nerve cells known as rods and cones.
The corneas refractive power bends the light rays so they travel freely through the pupil, an opening at the middle of the eye where light enters the iris. When you see a pupil getting bigger or smaller, in fact, the iris is controlling pupil refraction, responding to the strength of the light entering the eye. The reverse happens under bright conditions, where the iris is protecting the pupil to keep too much light entering your eyes. In low-light conditions, the iris will force the pupil to widen, allowing as much light into your eyes as possible.
The iris and pupil both control how much light is allowed to enter the back of the eye. This is because the iris dilates the pupil, allowing more light to reach the retina, which in general will enhance night vision. The colored part of your eye, called the iris, controls the size of your pupil, which is the opening through which light passes.
The cornea and the lens help to concentrate light rays on the back of the eye (the retina). The lenses concentrate light through the vitreous humor, a clear, gel-like substance that fills the back of the eye and supports the retina. The lens focuses light to shine on the rear of the camera.
The lens behind it reshapes itself to bend and concentrate the light for the second time, to make sure that you get the clearest picture you can. By changing its shape, the lens works to shift your eyes focal distance, so you can concentrate on objects from different distances.
Change means by changing the size of the opening called pupil, the eye can alter the amount of light coming into it 30 times. The pupils vary in size to adapt to the amount of light available–smaller for bright light, larger for dim light.
This light passes through the pupil, which can contract (close) and expand (open). Once light passes through the pupil, it is going to pass through the eyes lenses. After this, light needs to pass through the eyes lens, which is the clear internal portion of your eyes.
After the light entering the eye passes through the cornea, it is curved back – into more precisely tuned focus – by a crystallized lens within the eye. Ideally, Light entering the eye is refracted, or redirected, so the light is focused in such a way as to produce a accurate picture on the retina. When Light bounces off of an object and arrives in your eyes, it needs to be curved to make sure its rays reach the retina in a focused position.
When you stare at an object, the light reflecting from the object enters the eye through the pupil and is focused by the optical components inside your eyes. Light bounces from the picture before you and comes into the eyes through the cornea. The cornea flexes light rays so they can get to your pupil, which is the dark central part of the eye. The cornea refractively bends (slants) light to make the thing you are looking at sharp.
After the cornea, iris, pupil, and the eyes lens all finish their jobs, the light finally hits your retina. Light bounces from your spouse, passes through the cornea — the clear front of your eyes — the pupil — the black circle — at the center of your iris — the colorful part of your eyes — and then the lenses in the cameras eyes. When light gets into the eye, it is focused to a spot in the macula, the tiny spot at the centre of the retina in the back of your eye.
The light then passes through a lens behind it and into the back of the eye, which is filled with a clear, gelatinous substance called vitreous, until it arrives at the retina, a layer that is light-sensitive in the back of the eye. When placed in front of the eyes, a convex lens acts to converge (bring) light together and push it forward more towards the retina, thus allowing a person with hyperopia to see well at all distances. When the concave lens is placed in front of the eye, it acts to dilate (spread) the light out and push the focus point farther backwards toward the retina.
To see, the eyes need to concentrate the light onto your retina, convert that light to electrical impulses, and send those impulses to the brain for interpretation. Before your brain can process the object or picture, special cells called photoreceptors have to turn the light into an electrical signal. The retina also contains a dark pigment called melanin (also found in skin and hair cells) — it decreases the reflection of the light as it enters your eyes.
