Biomedics 38 contacts from Coopervision are designed to provide the patient with crisp, clear vision while at the same time maintaining good ocular health. The parameters for these lenses make them especially suited for patients with high prescriptions, those who require greater oxygen transmissibility, patients who experience dryness, and those who wear their contacts for extended periods of time. Biomedics 38 are comprised of a hydrogel polymer, Polymacon. This polymer attracts and absorbs water molecules resulting in a nearly 40% water content for Biomedics 38. This is vitally important to the health of the cornea.
The cornea is covered with a corneal tear film. This film is responsible for maintaining a fluid environment necessary to act as a barrier against elements from the world around us. The tear film prevents harmful bacteria, allergens and other debris from infiltrating, infecting or irritating the surface of the cornea. In addition, the constant replenishment of tears prevents complications associated with dry eye syndrome and helps to maintain the structural integrity of the clear medium of the cornea preventing a compromise of visual acuity.
The hydrogel polymers used in Biomedics 38 attracts, absorbs and retains the moisture encountered with natural tears, lens rewetting drops and contact lens solutions. This makes it an ideal lens for older patients who may not produce the quality of tears they once enjoyed or who may work longer hours and not remove their contacts as frequently. These lenses are also more resistant to protein buildup which may develop if the patient does not observe a regular disinfecting regimen. This makes Biomedics 38 contacts a good choice for teenagers or non-compliant patients.
These lenses also provide six times more oxygen to the cornea than conventional planned replacement lenses. This is vitally important in maintaining good ocular health. If the cornea is deprived of oxygen, the body will initiate an autoimmune response in the form of new blood vessel growth. This condition is known as corneal neovascularization. In advanced cases, these new blood vessels will interrupt the flow of light over the course of the visual axis causing light to scatter and inducing irregular astigmatism and compromising the patient’s visual acuity.
Oxygen reaching the cornea may also be compromised by the patient’s prescription. The patient’s prescription is determined by the radius of curvature of the lens as it refracts light. Nearsightedness is corrected with a concave lens, whereas farsightedness is corrected using a convex lens. Due to the need for these designs, a patient having a high minus (or nearsighted) prescription may have contacts fitting closer to the cornea around the edges.
A patient having a high plus (or farsighted) prescription may have contacts fitting closer to the center of the cornea. This closeness of fit at either the edges or center may cause a deprivation of oxygen. Biomedics 38 have an aspheric design meaning the radius of curvature is much flatter allowing the lens to be more uniform in shape and preventing the problems associated with higher prescriptions.