Which Contact Lens to Use for Impaired Vision?
Bausch and Lomb brought the first soft contact lens to the US market in 1971. Since then, advances in optical technology have introduced different lenses to suit virtually all types of vision impairment. The majority fall into the soft lens category, although a proportion of people wear rigid gas permeable or RGP lenses.
Soft Contact Lenses
Preferred by most people as the contact lenses are instantly comfortable to wear once correct insertion and removal techniques are understood, soft lenses are made from thin plastic containing water. They fall into the following categories:
- Daily disposable lenses – for single use only, these ultra-thin lenses should be worn during the day then discarded at night. Whilst more expensive than other disposable lenses, no contact lens solution is required and they are good for occasional use alternating with glasses.
- Bi-monthly or monthly disposables – for daily wear up to the period specified, either 1-2 weeks or up to a month. Lenses should be removed at night and require daily cleaning to remove protein build-up and may need to be discarded before the specified time limit if experiencing discomfort.
- Extended wear contact lenses – these are designed to be worn continuously from 7 to 30 days depending on the specification, allowing oxygen to reach the eye even while asleep. Some opticians will not prescribe this type of contact lens due to the increased risk of infection as bacteria can build up more easily. The latest silicone hydrogel soft lens technology increases oxygen transmission by up to seven times but the risks of bacterial infection remain.
- Toric lenses – these allow people with astigmatism to wear soft contact lenses although some people, with severe cases of astigmatism, do not have a clear vision with toric lenses and may need to consider specialist scleral lenses which, being larger, rest on the white of the eye.
- Bifocal lenses – the solution for people in their mid-forties, when presbyopia sets in and it become harder to read things close up. Lenses are manufactured with two prescriptions, one for near sight and the other for long sight.
- Monovision lenses – an alternative for people who cannot wear bifocals, one lens has the prescription for long distance, the other for short distance.
Colored Contact Lenses
Another category within soft contact lenses, these are becoming more popular as a beauty product as well as for vision correction. Colored lenses are enhancing the existing eye color or change it completely and lenses are available in zero prescription or Plano-form for those who just want a different look. Whether lenses are worn for vision correction or not, users must consult a qualified eye care professional first to check their suitability for contact lens wear.
Gas Permeable RGP Lenses
RGP lenses are made from silicon-based plastics which allow oxygen to pass through the lens. Smaller than soft lenses, they allow more oxygen to reach the eye but they require a period of adjustment before being comfortable to wear all day. As they are intended for long term use, cleaning and weekly disinfection are more time consuming but these disadvantages are offset by the cost savings that can be made as, without a change in prescription, they can last several years. Modern RGP lenses are now also available as bifocals.
Special Effect Contact Lenses
These are lenses worn for theatrical or cosmetic purposes and are becoming highly popular for fancy dress parties. They are effectively colored lenses with crazy designs and, for safety reasons, should only be purchased from a reputable manufacturer such as Ciba Vision who produce the Wild Eyes range of special effect lenses.
Popular Contact Lens Brands
The main brands in the contact lens market are Acuvue from Johnson and Johnson; Freshlook and Focus from Ciba Vision; PureVision from Bausch and Lomb and Biomedics from Cooper Vision. It is important to discuss the best brand of the lens for a particular condition with an optometrist and ensure that a compatible contact lens solution is prescribed with the relevant brand.
Choose the Right Contact Lenses
Always visit an eye care professional to have eyes tested or re-tested before choosing new contact lenses, then match one of the many types of contact lenses available to your particular circumstances and buy online, if necessary, to obtain the best price.