Contact lenses are a precious creation of technology, which solves some of the problems of glasses, such as cosmetic reasons and practicality.

Contact lenses are a precious creation of technology, which solves some of the problems of glasses, such as cosmetic reasons and practicality.
Nevertheless, they are not without problems and because of having direct contact with the cornea, misuse can lead to serious problems of the eyes.

Contact lenses can be worn at any age, even in childhood. Children whose lenses were removed due to congenital cataracts, are obliged to wear contact lenses immediately after surgery. However, they require special attention and care and proper maintenance, so for most children we wait to develop a certain level of responsibility before granting contact lenses. This occurs most commonly during puberty, but in cases where the child plays sports or practices dancing (métiers that indicate some level of discipline) may be granted at younger ages.


The types of contact lenses

Contact lenses, depending on the material properties of the structure, are divided into soft, semi-hard and hard, with the latter being rarely used due to poor oxygenation of the cornea. Soft contact lenses are the ones most commonly used, mainly because of the comfort they offer.
The child may get used to them from the very first application and can be used in sports and other related activities.

They however have the disadvantage that they absorb water from the eye and are not recommended if the child has dry eyes. The semi-hard contact lenses are rarely used, due to the longer period that the child needs to get used to them. They are more resistant than the soft ones, they do not absorb water, they allow more oxygen to pass to the eye, while can be combined with virtually with any medication.

As for their durability, we distinguish contact lenses in categories such as daily, monthly, bimonthly, quarterly and annual. All contact lenses though, must be removed during the nocturnal bedtime. Newer lenses with high oxygen permeability allow the user to sleep while wearing them and to wear them up to 30 consecutive days, though generally, they are not suitable for children, where complications from a continued use are greater.

Excluding lenses that correct the spherical refractive abnormalities (myopia and hyperopia), toric contact lenses suitable for astigmatism are also available.


Problems associated with the use of contact lenses

As already mentioned, contact lenses are not suitable for children or adolescents who cannot demonstrate responsibility and discipline. Due to the direct contact with the cornea, they can create problems such as injuries and infections if not used or maintained properly.

Infections caused by the use of contact lenses can be very serious and may even extend to the inner part of the eye. Some of the responsible germs, such as Pseudomonas, are so toxic, that can cause irreversible damage within a few hours. So each symptom that may occur during the use of lenses, such as pain, discomfort, redness etc., is an emergency situation and needs the immediate assistance of an ophthalmologist.

Apart from lenses themselves, solutions used for the cleaning and maintenance can also be responsible for infections and other problems. Some of them contain hydrogen peroxide (Η2Ο2) or other preservatives, which must be neutralized before the lenses are ready for use.

If the required time to neutralize has not passed and lenses are worn, they immediately cause toxic keratitis with severe pain and hyperemia.