Types of Contact Lenses
Types range from flexible soft lenses to rigid gas permeable lenses, their greater rigidity offering better focussing for difficult astigmatic patients, as well as providing more interchange of tear film. This was important when older style soft lenses were poor in transmitting oxygen, which is vital for good corneal health.
Nowadays more and more soft lenses are made out of a variety of materials with differing amounts of oxygen interchange through the lens. Let’s take you through some of the buzzwords you might hear.
The standard hydrogel lenses now available for daily disposable wear have a limited number of benefits given that each lens is thrown away each day. Therefore, designing and paying for longevity makes no sense. So also do other treatments to the lens which improve vision and comfort but are too expensive to use on daily disposables. It would be like using aspheric thin lens and coating technology on your spec lenses for your spare pair in the dash. Great if you can afford it! However, for something which you wear every day next to and touching your cornea, you would think most people would, if they could afford it, wear the best available contact lens. Indeed, better lenses have a greater longevity and therefore over a year’s wear the cost difference is not that much.
The latest upgrade in material is Silicone. This material gives fantastic oxygen permeability and it also allows the surface to be plasma treated which gives greater comfort, stay cleaner lenses and greater wettability. The plasma option is well worth having if available in your lens design. “New wave front technology” has been introduced for the actual lens make-up providing clearing and crisper vision in the same way aspherical lenses do for spectacle wearers.
Such companies have broadened the population base that can gain great benefit from wearing contact lenses because of another technology which allows soft lenses to be lathe cut to a “made to measure shape” to your cornea, allowing not only those with high astigmatism to wear lenses but those with damaged or misshapen corneas due to ocular problems such as keratoconus, to wear lenses.
The speed of the technological change in the last year has created a much larger market in those who can wear lenses and in those who want to wear better lenses. It is said that the wave front technology mentioned earlier can help those with early reading problems by allowing them to continue with single vision contact lenses longer. Nowadays, when that is not sufficient there are many new bifocal and varifocal contact lenses being made available within the market.
So what’s all this techno stuff done to the market? Basically better quality lenses now available much cheaper can be packed as fortnightly, monthly or for astigmatic or lathe cut lenses, into 3 month packs.
As word gets out about these more comfortable lenses we foresee the slow down of the one size fits all lenses for dailies and we have already seen a huge additional take up of longer modality lenses, especially the fortnightly packs for which a number of manufacturers have produced new silicone ranges.
Most of these lenses are silicone, some with plasma treatments and most with a handy easy to see tint.
Lenses are also available in tints to enhance your eye colour or to change it!