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Understanding the eye

To understand how contact lenses work, you first want to grasp a little bit concerning the eye. At its most simple, light reflects off an object and passes by means of the cornea, the clear covering of the eye. Next it travels to the pupil, the black part of the eye, after which via the lens, which focuses the rays on the retina at the back of the eye.

The retina is full of things called rods and cones and these take the light and convert it to electrical impulses which are then despatched to the brain for processing. If you get blurred vision, this is due to something called 'refractive errors' and is when the form of the eye stops the light reaching the retina directly and leads to distortion.

Fixing these errors

So to fix those errors, we use a tiny plastic lens that corrects them by creating a film that makes contact with the eye (hence - contact lenses). They work in the same method as glasses to focus the light on the retina and allow the eye to work properly. There are a number of different types of errors that leads to totally different problems and require totally different prescriptions to correct.

Myopia or close to-sightedness is the place object far-off seem blurred while objects shut by seem clear. This occurred when the light coming into the eye is not correctly centered and is caused by the form of the eye. This is among the most common conditions and there are various contact lenses that appropriate it.

Hyperopia or farsightedness is the opposite, kpop2 the place items close by are blurred however these further away are clear. Again, this is relatively common and there are many lenses to right it.

Presbyopia is an age-associated situation much like hyperopia the place items close by change into blurry but comes from a distinct cause. While hyperopia comes from the shape of the eye, presbyopia comes from the eye lens hardening with age. To right the condition, multifocal lenses are often used as they will clear each the near and the far blurriness.

Finally, astigmatism is a condition the place the irregular shape of the cornea or the lens stops the eye from focusing the light on the retina. A special category of lens is used to correct this condition, called a toric contact lens. Often, an image of a ball can be used to visualise the different - a sphere lens is sort of a beach ball where a toric lens is more like a rugby ball.
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