What Are Toric Contact Lenses And How Do They Work?
Topics covered in this article:
- options for mild astigmatism
- soft or GP toric lenses
- three choices in toric lenses
- disposable, colored and others
Have you ever been told that unfortunately you cannot wear soft lenses because you suffer from astigmatism?
Or have you ever been told that contact lenses for astigmatism, the so-called toric lenses, are not available in the disposable version, for frequent replacement, as multifocal lenses, or in the colored variations?
Well, once all those claims were indeed true, but today that is no longer the case. Only if you have received a particularly complex prescription from your specialist does this still apply, but in almost all cases your astigmatism can probably be corrected by wearing soft lenses, and you also have numerous options available from which you can choose.
What are toric contact lenses?
An eye that suffers from astigmatism has different degrees of myopia or hyperopia in different meridians of the eye. A toric contact lens has a special design to accurately correct vision in all meridians of the eye by aligning the associated lens power to the front of each meridian.
To achieve this goal, toric lenses for astigmatism have two additional properties that make them different from the classic spherical lenses that only correct nearsightedness or farsightedness:
- different powers in different meridians of the lens
- a mechanism that allows the lens to rotate to the correct position so that the meridians of the lens can align the correct direction with the associated meridians of the eye to achieve clear vision.
Toric designs are available in both soft contact lenses and rigid gas permeable (abbreviated as RGP or GP) contact lenses. But in general, when people talk about toric contact lenses, they are usually referring to toric soft lenses, which are more common than toric GP lenses.
Spherical lenses have the same power everywhere on the lens, and it does not matter if the lens rotates on your eye.
Toric lenses have two different powers in the lens, so they must remain in the correct position to provide the best visual vision to the wearer of the lenses.
Some toric lenses are given extra ballast and are therefore heavier below to prevent the lens from rotating.
What is the cost of toric contact lenses?
Toric contact lenses have an extra price tag. Adjusting contact lenses for astigmatism – whether it concerns toric soft lenses or toric GP lenses – simply requires more time from your specialist and also requires more expertise to adjust this type of lens than is the case with spherical lenses.
It is therefore understandable that adjusting a toric contact lens will be more expensive than adjusting a classic lens. Moreover, the lenses themselves are also a lot more expensive than spherical lenses.
Options for people who suffer from a mild form of astigmatism
If you are struggling with a mild degree of astigmatism, and we are talking about less than 1.00 diopter, then you could probably wear an ordinary spherical GP lens or even a spherical soft lens to successfully correct this condition.
How can you see if there is a treatment for your form of astigmatism?
Spherical GP lenses can correct soft forms of astigmatism because they were made of sturdy plastic and do not adapt to the asymmetrical shape of the upper surface of an eye that suffers from astigmatism.
GP lenses, on the other hand, optically replace the astigmatic curves of the retina with the spherical front and rear surfaces of the lens to achieve better vision.
Spherical gas-permeable lenses can also correct astigmatism greater than 1.00 diopter, but a spherical design is usually less comfortable for the eyes in people who suffer from a high form of astigmatism.
Toric GP lenses, which have an asymmetrical rear surface, are more comfortable on eyes with a greater degree of astigmatism of the retina because the rear surface of the lens fits better and more closely to the shape of the eye that suffers from astigmatism.
However, some soft lenses have sufficient thickness and rigidity to mask small forms of astigmatism and to provide acceptable vision in cases of astigmatism that is lower than 1.00 D.
The patient's satisfaction with this treatment depends on what his or her expectations are and his or her willingness to sacrifice some clarity of vision in exchange for the comfort and convenience of wearing a spherical soft lens.
Special aspherical soft lenses designed to reduce the spherical aberrations of the eye are another option in cases of mild astigmatism.
This ability to correct aberrations by means of soft lenses can better help some people to offer an answer to their astigmatism and thus be able to see better than by wearing a toric lens.
Should you choose soft or RGP lenses in the fight against astigmatism?
As mentioned above, gas-permeable lenses retain their shape on the retina better than soft lenses and they tend to provide better vision than soft toric lenses.
We do not notice this degree of difference in visual clarity in some contact lens wearers, but if you are rather picky about your vision, you may well appreciate this.
However, some people who clearly need the correction of their astigmatism will still opt for soft toric lenses instead of GP lenses because soft lenses provide instant comfort.
Colored, disposable and multifocal toric choices
There are many brands of soft toric lenses available today. Your specialist in the field can therefore make the choice for the brand that offers the best characteristics for your specific eye problems.
Toric lenses are available in both the frequently replaceable version, as a short-term replacement lens, and even as a daily disposable lens.
Toric soft lenses are also available in numerous colors that either change or underline your natural eye color. Some toric colored lenses can simply be thrown away after use, but depending on the color and your prescription, you can also opt for non-disposable toric lenses with a conventional replacement schedule.
Multifocal toric lenses are available for the correction of astigmatism and presbyopia. These are usually not available in a disposable version. There are a number of soft toric multifocal brands, but an RGP lens is often prescribed in these cases.
Silicone hydrogel toric lenses
A number of toric silicone hydrogel brands are available to consumers, ranging from one to 30 days of use. Custom-made silicone hydrogel lenses can be designed based on unusual prescriptions, including those for the treatment of irregular astigmatism.
These lenses are usually designed with a quarterly replacement schedule.
If you suffer from astigmatism and are interested in wearing contact lenses, visit an eye specialist who has experience in adjusting toric contact lenses. After a thorough examination, he or she will be able to tell you whether you qualify as a candidate for this type of lens and, if so, determine what the best toric lenses are to meet your specific needs.