In the early days of contact lenses, anyone with astigmatism was deemed unsuitable to wear them. Now – technology has advanced and unless your prescription is particularly complicated, your astigmatism may be corrected with multifocus contact lenses.
Hang on – you’ve lost me…what is astigmatism?
Astigmatism is a condition of the cornea of the eye. The cornea is the clear ‘layer’ of the eye that covers the iris (the colored part) and the pupil (the black dot in the middle). The function of the cornea is to let light into the eye, which allows you to see.
A ‘normal’ cornea is shaped like a tennis ball. Light enters it and is focused on a single point of the retina. The retina is a membrane lining the eye. It gets images via the lens of the eye which are changed into signals and sent to the brain via the optic nerve.
If you have astigmatism, your cornea is shaped more like an egg. This means that the light is focused on more than one point on the retina and this gives you blurry vision. It can also cause you to see shadows on letters when you’re reading, make you squint and cause double vision.
Toric Contact Lenses May Be The Answer…
A toric contact lens has two different strengths of prescription. These are at right angles to each other which corrects the astigmatism. Torics are available in soft lenses, rigid gas permeable ones and also multifocals.
In order to correct the astigmatism, the contact lens must stay in one position in the eye. There are two ways to achieve this.
1. The lenses have a ‘ballast’ – the bottom edge of the lens is thicker than the top edge, which prevents it moving around or
2. The middle of the lens is thicker than the top and bottom edges.
What Sort Of Torics Are Available?
* Daily disposable
* Monthly Disposable
* Frequent replacement
* Silicone hydrogel for 30 day wear
* Eye color changers
* Eye color enhancers
What Other Multifocal Contact Lenses Are There?
Aspheric contacts have different prescriptions blended across them. They are known as ‘simultaneous vision’ or ‘progressive’ lenses as your eyes have to learn how to choose to see through the appropriate prescription for what you are doing.
This sounds very complicated but aspherics are the most popular type of multifocal contact lens so it can’t be that difficult!
Many people can and do. There may be a period of trial and error while you work with your eye care professional to find what’s best.
Most multi-focal contact lens manufacturers are aware that not everyone will be able to wear them. For this reason, they offer a warranty on their lenses so that if you’re unlucky and can’t get on with them, you can get a different pair of lenses or a pair of spectacles. However, part of the money that you pay to have contact lenses fitted is for the professional time taken during that fitting and subsequent follow-ups. So you may not get back the whole amount that you paid to try the multi-focals. However, you should leave the eye doctor with some form of eyewear that corrects your vision.
Filed under: Eye Problems & Diseases
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