Purevision silicone hydrogel lenses by Bausch and Lomb are the latest in a generation of hydrogel technologies designed to provide the patient with the best visual clarity possible while maintaining a health cornea. Unlike traditional silicone hydrogels, they are specially treated to prevent the buildup of visually compromising protein deposits using their patented Performa surface process. Coupled with the Aergel silicone hydrogel, Purevision lenses will prevent many of the complications associated with conventional planned replacement lenses. They provide more oxygen, maintain moisture and prevent the growth of bacteria and buildup of allergens.
Purevision’s Performa surface process is designed to prevent harmful debris and proteins from building up on the contact surface while allowing the lens to remain comfortable over the course of wear. This is accomplished through a steady bombardment of electrically excited gas molecules to the lens surface that transforms it from a silicone hydrogel polymer to a silicone silicate.
This process allows the surface to be combined with other agents allowing the lens to become extremely viscous while still maintaining the ability to retain moisture and transmit oxygen effectively. This process is better than a coating because it forms a compound material with the lens; therefore, there is no risk the silicate will wear off. This material is now inherent to the properties of the lens matrix, since the base component of the lens is comprised of the silicone hydrogel material referred to as AerGel.
AerGel is a remarkable material in itself. It is one of the lightest solids known to man and comprised of 99.8% air. It assists in controlling the amount of moisture retained within the lens matrix and helps to facilitate the free flow of oxygen. Additionally, Purevision lenses have a rounded edge profile which facilitates a comfortable interaction between the conjunctival tissue and the lens edge for a comfortable fitting lens that stays with the patient throughout the day.
Maintaining the fluid environment of the cornea is extremely important when assessing the interaction between the eye and contact lens. If dry eye symptoms are allowed to develop, not only will the patient experience discomfort, but he/she will also be more susceptible to bacterial colonization, protein deposits and allergen buildup.
Purevision lenses are comprised of a water content of 36% allowing the eye to retain moisture throughout the course of wear. In addition, these lenses provide the patient with six times the amount of oxygen typically associated with conventional planned replacement lenses. If deprived of oxygen the eye will attempt to compensate by initiating an autoimmune response in the form of new blood vessel growth. This process is known as corneal neovascularization and becomes extremely problematic when the new blood vessels begin to encroach on the visual axis; the pathway light uses to travel to the retina allowing the process of vision to occur. The interference scatters light rays inducing irregular astigmatism and depending on degree of neovascularization may severely compromise vision. PureVision lenses prevent all the major complications associated with contact lens wear providing the patient with crisp, clear vision as well as peace of mind.