Abstract
Ophthalmic treatments using contact lenses are now used by more and more specialists around the world. Improving contact lens (CL) materials is a condition that is constantly evolving. Contact lens materials are usually composed of polymer hydrogel or silicone hydrogel. The materials used for night contact lenses are gas permeable and they gradual flatten the center of the cornea which decreases the progression of myopia or myopic astigmatism. The aim of this study is to identify, in correlation with the chemical interactions between structural components of contact lenses and their biocompatibility with the surface layer and microtopography of the cornea or sclera, different incidents that occur in patients who have used rigid gas permeable contact lenses. The study was performed on a group of 10 patients who had a follow-up period between 4 and 6 years, who presented regularly for eye examinations. The following clinical parameters were analyzed: ocular refraction before and after wearing night contact lenses, types of contact lens materials, appearance of corneal topography, biomicroscopic examination of the anterior segment of the eye, keratometry, ocular comfort, as well as other incidents regarding this type of lenses. Difficulties caused by wearing contact lenses at night arose due to poor hygiene and maintenance in two cases or due to interruption of lens wear in one case.
Highlights
IntroductionThe materials used to make contact lenses are usually composed of polymer hydrogel or silicone hydrogel
A contact lens (CL) is a device placed on the surface of the cornea or sclera to correct ametropia or it may be used for other ocular therapeutic purposes
gas permeable (GP) contact lenses are usually created from fluorosilicone acrylates, have been and are still used for the treatment of keratoconus, for the correction of high astigmatism and in ortho keratology [1, 2]
Summary
The materials used to make contact lenses are usually composed of polymer hydrogel or silicone hydrogel. In 1936, a hybrid contact lens was designed, consisting of a central glass part corresponding to the cornea and a peripheral scleral PMMA portion. The scleral lenses were created from PMMA for both central (corneal) and peripheral (scleral) portion [1]. In 1937 the first gas permeable (GP) contact lens with cellulose acetate was developed. In 1974 cellulose acetate butyrate was introduced, it was softer than PMMA, but had low oxygen permeability. GP contact lenses are usually created from fluorosilicone acrylates, have been and are still used for the treatment of keratoconus, for the correction of high astigmatism and in ortho keratology [1, 2]
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