Understanding the eye
To understand how contact lenses work, you first want to understand slightly concerning the eye. At its most elementary, light reflects off an object and passes by way of the cornea, the clear covering of the eye. Subsequent it travels to the pupil, the black part of the eye, after which by means of the lens, which focuses the rays on the retina at the back of the eye.
The retina is filled with things called rods and cones and these take the light and convert it to electrical impulses which are then sent to the brain for processing. Once you get blurred vision, this is because of 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 making a film that makes contact with the eye (hence - contact lenses). They work in the same means 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 completely different problems and require totally different prescriptions to correct.
Myopia or near-sightedness is where object distant seem blurred while objects shut by appear clear. This happened when the light coming into the eye is not correctly targeted and is caused by the shape of the eye. This is likely one of the most common circumstances and there are various contact lenses that appropriate it.
Hyperopia or farsightedness is the opposite, the place items shut by are blurred however those further away are clear. Once more, this is comparatively widespread and there are lots of lenses to appropriate it.
Presbyopia is an age-associated situation just like hyperopia the place objects shut by become blurry however comes from a different cause. While hyperopia comes from the shape of the eye, presbyopia comes from the eye lens hardening with age. To correct the condition, multifocal lenses are often used as they'll clear each the close to and kpop2
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 class of lens is used to correct this situation, called a toric contact lens. Often, an image of a ball can be utilized to visualise the completely different - a sphere lens is like a beach ball where a toric lens is more like a rugby ball.