Soft Multifocal Contact Lenses
Soft multifocal contact lenses improved in their success rate as design parameters were driven forward to accommodate the large numbers of aging baby boomers. Today there are a number of options available in disposable soft multifocal contact lenses to meet the needs of those passing the age mark of forty. These contact lens designs are optimized by several methods.
The Basics of Soft Multifocal Contact Lenses
All soft multifocal contact lenses are considered to be “simultaneous designs” This means both clear distance and near vision are present at the same time. The brain learns how to focus in on the desired image for the task at hand. The images are obtained by overlapping a central ring of distance (or near) and the opposing near (or distance) surrounds the central ring. These areas have to overlap within the pupil for both to be in focus at the same time. Some contact lenses are only made with the central ring for one focal distance while other offer a central ring of distance or near. Sometimes the focus is fixed within the zones and other lenses use a varying design (aspheric) for a smoother transition.
Important Factors in Fittings For Soft Multifocal Contact Lens Design
Perhaps the most important factor in getting fit for soft multifocal contact lenses is making sure the dominant eye is biased for good distance vision. For safety, driving requires that you see clearly at distance. It also just seems to work better when the dominant eye has the best distance vision of the two eyes. When one eye is more biased for distance it is considered to be a form of “modified monovision”. Monovision was the old way of correcting presbyopia (the over 40 vision problem that requires help at near). Presbyopia occurs when the lens inside the eye has grown too large and become too rigid for the muscles to change it’s shape so it can accommodate for up close reading. With monovision, one eye was fit for distance and the other was fit for near. While this can work, it does disrupt vision more as there is no overlap between the two eyes. Soft multifocal contact lenses always have overlap, even when they are fit as modified monovision.
The second most important factor in fitting soft multifocal contact lenses is making sure the distance and near zones overlap within the pupil. Most lenses have only one fixed size for the zones but there are lenses available where this can be adjusted if needed. Sometimes this is the difference that allows for a successful fit when all other methods have failed.
The third important factor in fitting soft multifocal contact lenses is making sure the powers are adjusted for the types of visual tasks you do most of the time. Soft multifocal contact lenses today generally do not yield perfect vision. What you should be aiming for is seeing well with the things that occupy most of your time. When it comes down to things like reading tiny print, unless you do that for a living, you might need some additional help in a pair of glasses over your contact lenses. On the other hand, you should be able to read the size print that you spend most of your time working with.
The Fitting Process
Don’t expect the first pair of soft multifocal contact lenses you use to be the final product. In our Fort Collins Optometrist Practice we always start with trial lenses before you commit to ordering an annual supply. Patients may go through a number of different soft multifocal contact lenses before we reach a point where no more improvement can be made. We treat numerous contact lens patients with dry eye syndrome, and often utilize special materials like Hioxifilcon or treated silicone materials to help lessen the impact of dry eyes and the dry climate around Fort Collins.
Technology is allowing many more people to be successful wearing soft multifocal contact lenses. Having patience and being willing to trade off a small amount of clarity for convenience will have you seeing distance and near in your contact lenses like you are twenty once more!