Soflens 59 lenses by Bausch and Lomb are designed to provide the patient with clear vision, prevent the buildup of protein deposits and maximum comfort. These lenses are a time-tested design released in 1993. This requires more attention on behalf of the patient to a hygienic contact lens disinfecting regimen and removal of these lenses on a nightly basis to prevent complications associated with oxygen deprivation.
These lenses are available in a wide variety of powers and parameters making them an economical choice for markets outside the United States as long as the patient is conscientiously aware misuse will cause significant complications. These lenses are manufactured using a hydrophilic polymer to maintain moisture and prevent irritation due to dry eye syndrome. This hydrophilic polymer, hilafilcon B, is comprised of 41% water content allowing the patient better comfort than previous conventional soft lens designs.
The significant advantage of Soflens 59 lenses is their ability to resist the buildup of proteins. A patient’s natural tears contain proteins, lipids, and other nutrients necessary for corneal health. The proteins found in the tear are two types: denatured and native. Denatured proteins are ionic meaning they will adhere easily to other materials having a reciprocal charge. Soflens 59 are designed with a non-ionic barrier meaning that rather than attracting denatured proteins they repel them. This results an almost non-existent chance protein strands will accumulate and create a deposits.
Protein deposits on the contact surface will warp the cornea causing light to be refracted at different angles, scattering it and inducing irregular astigmatism. Once the cornea becomes warped in this way it is extremely difficult for the eyecare professional to correct for it using contacts or spectacle lenses. Visual acuity will become significantly compromised.
Oxygen is another significant concern when assessing a patient’s corneal health as it relates to contact lens wear. If the cornea is deprived of oxygen, it will attempt to rectify the problem by growing new blood vessels to the affected area. Blood vessels carry nutrients and oxygen to bodily tissues. The corneal tissues likewise require a steady supply of oxygen. When deprived, the cornea will undergo a process known as corneal neovascularization. This complication will attempt to bring oxygen to the affected areas of diminished supply through an ingrowth of new blood vessels. In advanced cases, corneal neovascularization will create a webbing affect over the visual axis; the pathway light travels during the process of vision. This results in a scattering of light rays inducing irregular astigmatism and compromising the patient’s vision.
Since Soflens 59 lenses are an older generation of contacts they do not provide the eye with as much oxygen as today’s newer hydrogel planned replacement lenses. Patient’s wearing Soflens 59 lenses should remove them nightly to prevent the oxygen deprivation that may result in corneal neovascularization. Although Soflens 59 lenses may be a more economical choice for a few patients, special consideration must be given to wearing schedules, disinfection and care.