Contact lenses jargon buster
Astigmatism is when your eye is not entirely round. Most people eyes are, to some degree, rugby ball shaped instead. In the past if you had a high degree of astigmatism this may have limited the types of contact lenses available to you, but now soft toric lenses are available in a wider range of options. Rigid lenses in gas permeable materials are another good solution, either as small corneal lenses or mini scleral lenses which can help people with severe or irregular astigmatism. Ask your contact lens optician if you would like to try toric lenses.
The cornea is the clear part of the front of the eye. Light passes through the cornea. The curvature of the cornea bends light to help it focus on the retina at the back of the eye. If you wear contact lenses they float on the bed of tears that covers the cornea at all times.
- Daily disposableOpen
More and more people are wearing daily disposable contact lenses. These soft lenses can be super-thin as they are only worn one time. This ensures that they are comfortable and easy to get used to, and allow oxygen to flow through easily to the front of the eye where it is needed. They are not designed to withstand the rigors of cleaning and should be thrown away after one use.
A dioptre is the unit of measurement for spectacle lenses. The optician will also use dioptres to describe how long or short sighted you are and/or how much astigmatism you have. Ask your optician to explain your spectacle or contact lens prescription.
- Extended wearOpen
Unlike most lenses, extended wear contact lenses are designed to be worn for more than one day without removal. They tend to be thinner than daily wear lenses and made of materials that allow more oxygen to reach the cornea. You may wear the lenses for a week or a month, depending on the advice from your optician. Research has shown a higher risk of eye infection from extended wear lenses, so some practitioners prefer to advise flexible wear with some overnight wear. Always ask your contact lens optician for advice before wearing lenses overnight.
Hydrophilic materials are ‘water loving’. Soft contact lenses are made of pliable hydrophilic plastics called hydrogels. Hydrogels absorb lots of water so the lenses stay soft and supple and allow oxygen to flow freely through to where they are needed on the surface of the cornea, the front of your eye.
Hypoallergenic materials are low allergy. They are used to make contact lenses because they are unlikely to cause allergies when worn. If you have any concerns about irritation when wearing contact lenses, speak to your optician.
Multifocal contact lenses are suitable for people who might wear bifocal or varifocal spectacles, because they need different prescriptions for distance and near vision. If this sounds like you, ask your contact lens optician about trying out multifocal lenses.
A toric lens has a rugby ball shaped curve, and is what you need if you have astigmatism, where your eye is rugby ball shaped too. There are many different strengths of toric contact lens, making the suitable for a wide range of people who are long or short sighted with astigmatism. Ask your contact lens optician if you would like to try toric lenses.