There are soft hydrogel or silicone-hydrogel lenses, rigid gas permeable lenses, hybrid lenses (rigid in the center and soft on the periphery)… Each lens has its advantages and will correspond better to an optical correction, to the pathology of the cornea, to an environment, or to a type of use. In any case, your ophthalmologist will determine with you which lens material is best for you.
Soft Hydrogel Lenses
This material has been around for decades and has been improved by additions of wetting or comforting agents. This very flexible material has the advantage of being very comfortable because it is largely made up of water. However, the transmissibility of oxygen through the material is limited. This material is essentially reserved for occasional wear or for wearers who have tears with a high lipid content because the material is more resistant to fouling than other soft Ortho-K lens materials.
Soft Silicone-Hydrogel Lenses
But what is it, then? It is the very last material used in the realization of soft lenses. Its main quality is to allow very good oxygenation of the eye thanks to the better permeability of this material. This material respects the eye health of contact lens wearers, it is the assurance for them to be able to wear their lenses longer with better comfort. The tonicity of the material also allows easier installation for first-time wearers. Please note: all silicone hydrogel lenses are different, and each laboratory uses its own material chemistries. Always ask your ophthalmologist for advice before changing lenses.
Rigid Gas Permeable Lenses
These lenses are the first lenses to have existed. Small in size, they rest on the tears and not on the cornea like soft lenses. They give excellent results in cases of particular corrections or forms of corneas or tolerance. The comfort is not immediate but after a few weeks, these lenses bring full satisfaction to the wearers who are equipped with them.
These lenses are as their name suggests hybrid with a rigid center and a flexible periphery.
They are mainly used in the treatment of corneal pathologies.
Color or not, the lens remains a foreign body for your eyes… and we only have two. So take care of it and before any change, always ask your qualified optician optometrist for advice.
Read and understand my contact lens prescription
The prescription for contact lenses contains specific indications for the prescription of lenses. Here are the different parameters to help you read and understand your contact lens prescription.
Diameter: it corresponds to the size of the lens. It must be in line with the size of the cornea, too big or too small, it can cause significant discomfort.
BC (Base Curve): this is the radius of curvature of the lens. It must be adapted to your cornea to bring you the best comfort. Too large a radius will make your lens unstable and uncomfortable; too small a radius will result in tightness that can eventually lead to lens intolerance. In both cases, your adaptation will not be optimal and this may lead to the abandonment of the wearing of contact lenses.
Sphere: it corresponds to the correction. Either myopia (it is then preceded by a “–” sign) or hyperopia (it is then preceded by a “+” sign).
Cylinder / Axis: they correct astigmatism. These two values are related and respectively indicate the value and the main direction of your astigmatism.
Progressive lenses: the terms below correspond only to progressive lenses, allowing presbyopes to see both far and near.
Add Low/Med/High or +1.00/+1.50/+2.00: corresponds to the level of addition necessary for near vision.N (Near) / D (Distance): indicates that the lens favors near (N) or far (D) vision.