Types of contact lenses or contact lenses
One of the alternatives More popular to glasses are contact lenses or contact lenses. The choice between wearing contact lenses instead of glasses is a very personal one. We know that in most cases, it is due to aesthetic causes or discomfort glasses suppose to carry out certain activities such as sportTherefore, it is vitally important to know the types of contact lenses or contact lenses and the possibilities that each one of them gives us.
However, there are those who are doomed to choice of lenses not only for an aesthetic fact but due to an anatomical problem at the level of the nasal bridge which determines that the glasses do not fit correctly.
Types of contact lenses or contact lenses
One of the alternatives More popular to glasses are contact lenses or contact lenses. The choice between wearing contact lenses instead of glasses is a very personal one. We know that in most cases, it is due to aesthetic causes or discomfort glasses suppose to carry out certain activities such as sportTherefore, it is vitally important to know the types of contact lenses or contact lenses and the possibilities that each one of them gives us.
However, there are those who are doomed to choice of lenses not only for an aesthetic fact but due to an anatomical problem at the level of the nasal bridge which determines that the glasses do not fit correctly.
Types of contact lenses
Basically we can differentiate between rigid and soft lenses. The first, in its beginnings, were made with plastics of the polymethylmethacrylate type. But, due to the complications that these materials caused, they were replaced by others, basically permeable to oxygen, to let "the cornea breathe". For this reason, they are called with the acronym RGP, which obey Rigid Gas Permeable contact lenses.
Rigid contact lenses
All the rigid lenses they have the advantage de simultaneously correct the spherical defects of myopia o farsightedness and astigmatism; since the deformity of the cornea is regularized thanks to the lens acts as a mold that shapes eliminating that irregularity.
The main drawback they present is that, due to that ability to mold, its adaptation is more laborious, the fitter must calculate the parameters of the contact lens so that it fits correctly, like the tailor who makes a tailored suit.
For its part, the user must get used to the inconvenience that these cause at the beginning, which will gradually disappear as the adaptation process progresses.
Soft lenses
For improve adaptation conditions and comfort the size of the contact lenses, the soft lenses, made with materials based on hydrogel that incorporates water into its molecule, making it more flexible. The higher the water concentration, the better the conditions for flexibility and oxygen transport, basic condition for the tolerance of contact lenses as a consequence of the physiology of the cornea. On the contrary, High hydration soft lenses are more fragile and easily contaminable, both by microorganisms and by deposits of materials found in the tear or in the environment (fat, makeup, etc.).
Currently, the number of soft lens wearers far exceeds rigid contact lens wearers, because of his greater comfort and because they have solved much of the problems of contamination and deterioration, typical of materials with high water content. The solution has been move to replace lenses very often, each month, semana or even to diario. If we dispose of the lenses and replace them with new ones, it is not necessary to be very careful with them, because we do not give them time to deteriorate or contaminate, thus guaranteeing health safety together with greater comfort in carrying.
The problem appears when recommendations are not followed and lenses are not replaced as often. By lengthening this period, we give the material time to degrade by fixing on it elements that can induce allergic reactions or facilitate the fixation of microorganisms, at increased risk of infections.
Other classifications of contact lenses
Material from which they are manufactured
They can be contact lenses of:
- Gas Permeable (RGP) or hydrophilic, either conventional or silicone hydrogel (LH or LHISI).
- Hybrid contact lenses, which combine rigid material with hydrophilic material.
The regime of use
De daily use (take off to sleep), long-term use (up to 6 days without removing) or of continued use (up to 30 nights without removing them)
The frequency of replacement
Can be of one use only, replacement biweekly, monthly, quarterly o top (depending on the type of contact lens).
Lens design
- Spherical: to compensate nearsightedness or farsightedness.
- O-rings: to compensate astigmatism.
- Multifocal: to also compensate the presbyopia or special designs (keratoconus, keratoplasty, post surgery ...).
- ORTHO-K: to wear corrective lenses at night and not have to wear them during the day.
Conclusions about the use of contact lenses
La visual quality with contact lenses is very good. The fact that they are placed on the cornea eliminating the distance between the glasses and the eye has a very important implication in visual quality. On the other hand, also can incorporate filters, Like the ones of protection against ultraviolet radiation, filters that cut short-band frequencies, or can have different focuses: bifocal or progressive, although this last aspect is not fully achieved in optimal results.
However, as are in permanent contact with the eye, they can induce others serious problemsas corneal erosions o infections they can irreversibly affect vision.
Contact lens wearers should be aware of the potential risk they run. Therefore, it is essential that they follow the recommended instructions by going to scheduled reviews and that they ask to be visited as a matter of urgency in the face of any anomalous situation that is accompanied by strong ocular pain or loss of vision. In the present moment many of the patients with contact lens problems can appreciate the possibility of a refractive surgery, for which you must perform some tests and make the decision with your ophthalmologist.
