Refractive eye errors are extremely common. They occur when light that passes through the eye isn’t refracted directly onto the retina, which is the light-sensitive patch of cells at the back. This causes the signal that is sent by the retina to the brain via the optic nerve to appear garbled, and this causes our vision to appear blurred. There are several different types of refractive eye errors – nearsightedness (myopia), farsightedness (hyperopia) and astigmatism. All require the patients to wear prescription lenses to see clearly. Fortunately, this doesn’t mean that you have to suffer the inconvenience of glasses. Many patients with refractive eye errors opt to correct their vision using contact lenses.
There are many different types of contact lenses now widely available across the country. Some patients are found to be unsuitable for many of the ‘mainstream’ varieties of contact lenses. In these instances, you may be recommended to try a type of specialty contact lens instead.
Some of the patients that could benefit from specialty contact lenses include those who:
have been diagnosed with dry eye syndrome
have corneal scarring
have been diagnosed with keratoconus, a condition characterized by the bulging of the cornea
suffer from strabismus, a condition where the patient has an eye that turns in or out relative to the other
have suffered an injury to the eye
suffer from a peripheral corneal thinning disorder
are intolerant to other types of lenses
Our experienced eye care team will be able to advise you if you are likely to be a suitable candidate for specialty contact lenses.
There are primarily two types of specialty contact lenses. These are as follows:
Scleral lenses are a little different from regular contacts in that they are considerably larger in diameter. Most contact lenses are fairly small and cover only the colored part of the eye. Meanwhile, scleral lenses are so large that their edges rest on the whites of the eyes from which they take their name – the sclera. Their design means that they extend over the top of the cornea with a space between the back surface of the contact and the front part of the eye. The dome-shaped surface is completely smooth so that light refracts directly onto the retina so that the patient enjoys a clear vision.
The design of scleral lenses has another purpose too. The space that they create between the eye and contact ensures that the eyes receive sufficient oxygen and flow of natural tear film to remain healthy. This makes them a great option for people who have been diagnosed with dry eye syndrome, or for people who have bulging corneal tissue since there is space to accommodate this beneath the lens. Their extended size means that they are also more stable than conventional contact lenses.
Rigid gas permeable contact lenses have been around for a while, but many patients are still unaware of the advantages that they can offer them. As their name suggests, these lenses are rigid and made from durable plastic. They are able to retain their shape at all times, and this is one of the key elements of their longevity. However, unlike many other types of lenses, they are gas permeable. This means that oxygen can flow through the lens material and reach the eyes. As we know, this helps the eyes to remain healthy and makes these specialty contacts suitable for patients with dry eye syndrome. In fact, rigid gas permeable lenses have greater oxygen transmission capabilities than many types of soft contact lenses.
Like scleral lenses, they are fairly large, covering around 75% of the cornea. This gives patients enhanced stability that is often missing with conventional lenses. They are also easier to clean and place/remove than softer lenses, and their ability to retain their shape means that they provide crisper, sharper vision with enhanced clarity.
If conventional contact lenses aren’t a suitable option for you, but you want to avoid the inconvenience of glasses, specialty contacts may be an alternative solution to correct your refractive eye error. To discover more about what specialty contact lenses can do for you and your vision, please get in touch with our knowledgeable team.