The main way that silicone hydrogel contact lenses increase oxygen permeability is by adding silicone to the lens material. Compared to conventional hydrogel materials, which rely primarily on water content to assist oxygen transmission, silicone permits noticeably more oxygen to reach the cornea.
the possibility of getting the serious corneal infection known as microbial keratitis. is most closely linked to prolonged (overnight) contact lens usage of any kind. Due to the possibility of bacterial contamination and decreased oxygen supply to the cornea when you sleep, this practice can greatly raise your risk of infection.
By preventing damaging UV rays from reaching the cornea and internal structures of the eye, UV-blocking chemicals are added to contact lens materials with the aim of lowering the wearer's risk of cataract development and other ocular disorders associated with UV exposure.
The feature of multifocal contact lenses known as "simultaneous vision" refers to the ability of the wearer's eye to simultaneously receive images from the near and far zones. Depending on the viewing distance, the brain then chooses the clearest image, enabling continuous vision at various ranges without the need for manual correction.
RGP lenses feature a rear surface toric design to better fit and conform the lens to the toric, or irregularly shaped, cornea.
RGP lenses are surface treated with plasma to increase the lens's wettability and surface lubricity. Through the reduction of surface tension and improvement of tear distribution over the lens, this treatment alters the lens surface to make it more compatible with the tear film, improving comfort.
When discussing RPG lenses, apical clearance refers to the lens's vaulting over the corneal apex while preserving a little space between the lens and the cornea that is moistened with a thin coating of tears. This fitting technique is crucial for facilitating tear exchange, improving comfort, and guaranteeing that the cornea receives enough oxygen.
Low humidity settings can make lens dryness worse for people who wear soft contact lenses. Under some circumstances, the water in the hydrogel substance of the lens may evaporate more quickly than usual, causing lens shrinkage and increased friction between the lens and the surface of the eye to produce discomfort.
For astigmatic patients, the stabilizing mechanism of toric soft contact lenses is essential to achieving the best possible isual acuity. By maintaining the lens's right orientation on the eye, this mechanism makes sure that the astigmatic correction appropriately matches the astigmatism of the eye.
Patients with leratoconus require specially constructed keratoconic lenses to accommodate the conical shape of their cornea. Because these lenses are made to fit over the irregular shape of the cornea, they ensure a more stable fit and the proper amount of refractive correction, which improves comfort and visual acuity.
