Contact Lenses

Extended Wear Contact Lenses

New 'silicone-hydrogel' materials are changing the way contact lenses are used. These materials were initially designed to leave in your eyes while you sleep. This means no-fuss removing your lenses each night, no cleaning your lenses after you remove them, and not having to put your lenses back into your eyes the next morning.

Previously, soft contact lenses were made from materials which restricted the passage of oxygen to your eyes. As well as causing redness and some changes of function, this effect may also be responsible for some of the more serious complications which have been traditionally associated with contact lens wear.

The new materials allow the eye to 'breathe' normally, and scientific studies have shown that this provides great benefits for eye health. It is important to realise that use of contact lenses 'around the clock' may still mean that you have more chance of getting an eye infection and you should talk to your optometrist about the chances of this happening and what you can do to help avoid such conditions.

Some people who have sought relief from the inconvenience of handling and cleaning contact lenses have chosen to have laser surgery to correct their eyesight. However, this treatment is relatively expensive and is known to have possible complications including permanent vision loss. Daily disposable contact lenses offer another alternative which eliminates the step of daily cleaning of contact lenses and approaches spectacles in terms of safety among the various forms of eyesight correction. However, the new extended wear lenses offer a balance of properties that includes fitting and comfort superior to currently used soft lenses. The healthy ocular environment, combined with the remarkable convenience, may see silicone-hydrogels become the most prominent form of eyesight correction outside of spectacles.

Our practice can provide you with all appropriate advice that you need to make a choice about your eyesight correction. For more information and to assess your suitability to use these new lenses, please make an appointment for an eye examination.

Rigid Contact Lenses

Surveys have shown that patients are most concerned about vision and health when selecting contact lenses. Comfort is also important, but patients are more concerned about long-term comfort (following the adaptation period and at the end of a day) than initial comfort. Convenience and cost are also factors of importance to the consumer. Using these points of reference, it is easy to paint a positive picture about rigid gas permeable (RGP) lenses.

• They provide superior visual performance, particularly for patients with astigmatism.
• The physiological benefits are sufficient to support not only daily wear but also in some cases, extended wear as well.
• Following the initial adaptation period, comfort is usually equal to or greater than that of soft lenses.
• The simple care systems and longer lens life make RGP lenses convenient to care for and cost effective as well.
• Younger patients (and their parents) may also benefit from the reduction in myopic progression attributed to rigid lenses.
• The superior oxygen transmissibility afforded by high Dk rigid lenses is believed by many to be the key to achieving a lifetime of healthy vision with contact lenses.

Confirmation of many of the above benefits was gained in a study by Johnson and Schnider in which 20 patients, all non-contact lens wearers, wore a pair of rigid and a pair of soft lenses for six weeks each. All patients were myopic with low astigmatism (less than 0.75D), and thus considered prime soft lens spherical candidates, and the order of presentation of lens type was randomised between two groups.

The results showed that in a forced choice comparison at the end of the study, 40 per cent of patients preferred the rigid lenses over the soft, and 75 per cent of patients said they could wear rigid and soft equally well. These numbers contrast sharply with the 10-15 per cent market share for RGP lenses in the USA and Australian markets. The chief reasons for choosing the rigid lenses over the soft were clearer vision, easier care and handling, and greater convenience. Less corneal (the clear eye tissue over the pupil area) disturbance and lens damage were also observed for the rigid lenses as well.