What are toric contact lenses? | Astigmatism

What Are Toric Lenses?

The meaning of toric when it comes to a contact lens is essentially having two different curves instead of one to correct both astigmatism and long-sightedness or short-sightedness. Toric contact lenses are primarily soft lenses designed for people with astigmatism. Toric lenses correct astigmatism by using different optical powers and focal lengths than a standard lens. Standard lenses have a spherical surface. In a “normal" eye, the cornea and lens are smooth and the curves are equal. When you have astigmatism, the curves are not equal, and when light rays pass through your cornea and lens, they do not focus correctly on your retina, creating what's called a refractive error. Toric lenses have different powers in different meridians and it is often described that a non-stigmatic cornea looks like a 'football', whereas a toric cornea looks more like a rugby ball. 

Why Are Toric Lenses For Astigmatism So Expensive?

Toric lenses that correct astigmatism can be slightly more expensive than regular contact lenses that simply correct short-sightedness, this is due to several factors, toric lenses are far more labour-intensive to manufacture, the power range is far larger especially when you add on the axis and the cyl variables and there are far fewer sales per power.

Are Toric Lenses Easy To Get Used To?

If you have a mild to moderate amount of astigmatism, a relatively low refractive prescription and good eye health then you shouldn't have any problems being fitted with toric lenses.
Toric lenses have a reputation for being difficult to get used to, however, if you are willing to spend a little extra time with your optometrist then the improvement to your vision will be well rewarded.

A clinical study carried out in 2013 to evaluate whether people with astigmatism who are not wearing contact lenses can be fitted with toric lenses proved 88% of toric lens fittings were successful on the first attempt. 

What Are The Best Contact Lenses For Astigmatism?

Without a doubt, toric contact lenses are the best option for contact lens wearers with astigmatism. There are lots of toric contact lens options available but the specific brand and type of toric contact lens that's right for you can depend upon your individual needs.

Having discussed your lifestyle choices, your wearing schedule and the cost with your Optometrist he or she will recommend various options to you, this may involve, daily toric lenses, monthly toric lenses or one of the new generation hybrid contact lenses (HCLs). 

All toric lenses are designed to be comfortable for a full day's wear, some are even for extended wear lenses which means you can wear the lens for up to 7 nights without removing them.

Toric Contact Lenses For Astigmatism

Daily Toric Contact Lenses

Daily toric lenses for astigmatism are by far the most convenient and healthiest option as they can be disposed of each night and replaced by a fresh pair each morning.  This makes them an ideal choice if you have a busy lifestyle or don't want to wear lenses every day or want to wear contact lenses just for sport. One of the top-selling daily toric lenses is 1 Day Acuvue Moist for Astigmatism and one of the cheapest daily toric lenses is Soflens Daily Disposable for Astigmatism.

Two weekly Toric contact lenses

Although not the most popular choice of disposable lenses two weekly replacements offer a great choice between daily and monthly lenses. Whilst still requiring a nightly cleaning regime as their name implies they are renewed every two weeks this can make them cheaper than dailies and are often recommended by optometrists for people who suffer from dry eyes. One of the most popular bi-weekly contact lenses for astigmatism is Acuvue Oasys for Astigmatism

Monthly Toric contact lenses

Like two weekly lenses monthly toric contact lenses have been designed to be removed and cleaned at night before reinsertion the following morning to help prevent eye infections. 

Monthly toric lenses can work out the cheapest option and are ideal if you wear contact lenses every day and want to save some money and the environment - monthly contact lenses have the least impact on the environment.

One of the most popular monthly toric contact lenses is Biofinity Toric lenses they are also one of the cheapest, they can also be used as extended wear lenses allowing you to wear each lens up to seven nights, making them super convenient.

Toric Rigid Gas Permeable Lenses

Unlike soft contact lenses, rigid gas permeable (RGP) lenses don't flex to conform to the shape of the eye's surface., instead, they hold their form, and effectively replace the astigmatic surface of the cornea with a properly shaped spherical lens surface. This allows the lenses to correctly refract light entering the eye while compensating for astigmatism.

There is also no need for the lens to be weighted like toric lenses, so they are free to rotate on the cornea without affecting vision at all. However, there is a limit to the amount of astigmatism (about 3 dioptres) that can be corrected with a standard gas-permeable lens, without resorting to toric gas-permeable lenses.

Higher levels of astigmatism than 3 dioptres can easily be corrected with gas-permeable lenses utilizing special back curves that have different powers in different directions. 

The benefits of RGP's are that they offer a great clarity of vision (on par with your spectacles), they are available in a much larger power range with greater degrees of astigmatism and they last longer than soft toric contact lenses.

However, they do have their disadvantages. RGPs can take longer to fit and take much longer to get used to and you will need to take special care in cleaning and disinfecting your lenses as you don't dispose of them, also they are not available online for replacement.

Hybrid Toric Lenses

Hybrid lenses offer a unique solution, they have a rigid gas permeable centre to correct astigmatism with a surrounding soft lens "skirt". 

According to a leading optometrist journal Optician Online, ideal candidates for hybrid toric contact lenses are those suffering from low to high amounts of astigmatism, presbyopic astigmats (people with age-related farsightedness and astigmatism), soft toric contact lens wearers who can not achieve the same level of clarity as with their spectacles and run the risk of dropping out (including those who have already dropped out), sports people and anyone requiring enhanced vision.

The benefits of hybrid lenses are that they can offer the best of both worlds, the clearest vision of an RGP with the comfort of a soft contact lens.

The disadvantage of these lenses is the time they take to fit and not every Optometrist is willing to fit this type of lens. The insertion, removal and care of hybrid contact lenses is different from your regular soft lenses, so can mean learning a new technique and they are not available to buy online. 

Scleral Contact Lenses

Progressive astigmatism may indicate an underlying condition like keratoconus, which happens when your cornea thins and bulges out into a cone shape. If your astigmatism is progressive, you should consult your Optometrist about possible conditions that could cause this. It could be that scleral lenses may be recommended to help slow down the rate of progression of your astigmatism. 

In conclusion - the pros and cons of toric lens options will have to be weighed up carefully with your Optometrist. He/she will discuss with you what you want them for, and your lifestyle and take into consideration the amount of your astigmatism and other clinical information. You can then decide, in conjunction with your optometrist, which toric lens is best for you. 

For Further Information: 

What is Astigmatism?