Keratoconus and Hybrid Contact Lenses
For people with the eye condition Keratoconus, contact lenses are often the best way to get vision correction. RGP (Rigid Gas Permeable) contact lenses are the most common for people with the disease but, in some cases, a hybrid lens may be a better option.
A condition of the eye, Keratoconus causes the thinning of the front part of the eye, the Cornea, which results in it bulging outward into an irregular bulging 'conical' shape..
It is this distortion that causes the poor eyesight. This is because the light coming into the eye is scattered and can not be focused onto the retina correctly. This results in blurred vision and ghost images .
Spectacles and hydrogel contact lenses, which are sometimes just referred to as soft lenses, can be very effective where the condition is very mild, or when it is in the early phases. In the more advanced cases the Rigid Gas Permeable lens is more effective. This is because it keeps its own regular shape and a layer of tears forms underneath it, between the cornea and the contact lens. The combination forms and artificial single surface that acts like a regular shape cornea. The size of the Rigid Gas Permeable lens means that the inner surface of the eyelid can rub against the edge of the lens causing soreness or irritation.
Additionally the lens can become dislodged from the eye very easily, especially if the cornea has become steeply distorted..
An alternative that can be considered if this kind of 'edge' irritation occurs is the hybrid contact lens. The Rigid Gas Permeable lens is a lot smaller than a hydrogel (soft) contact lens. A hybrid contact lens is a combination of an RGP lens in the center with is then surrounded by a layer of hydrogel material around the outside.
Because the centre of the lens, the bit that goes over the cornea, is rigid it will maintain its own shape, trap the layer of fluid and form the single regular surface required for light to pass into the eye without being distorted. Because the softer hydrogel material surrounds the rigid edge of the lens it cushions it and this means that it lessens the sensation of the lens against the inside of the eye lid.
If you are struggling to deal with the sensations of wearing an RGP lens then a hybrid solution may be an effective option. Additionally they have less of a tendency to become dislodged and lost, and they may prove to offer greater comfort to people with dry eyes. They're not as easy to fit and remove as the Rigid Gas Permeable lens, and they tend to be more expensive.
About the Author
At Vision Life we answer the question, what is Keratoconus? We provide Information to both raise awareness of the condition and to help people who's lives have been impacted by the disease. Get a free information pack and newsletter at http://whatiskeratoconus.com
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