Are Contacts Right For You?
While there are very attractive choices available today when filling a prescription for eyeglasses, many people prefer to wear contact lenses for vision correction. Contacts usually provide vision clarity equal to and sometimes better than with eyeglasses. Sometimes, contact lens correction is not as good as that with glasses. A general understanding of what can be accomplished with contact lenses can help one make the right choice.
Nearsighted (minus power, myopia) and Farsighted (plus power, hyperopia) prescriptions with minimal to no astigmatism are corrected very well with spherical soft contact lenses. When the prescription is a higher amount, (above +/- 6.00 diopters), contacts almost always provide clearer visual acuity than that with glasses. Additionally, peripheral vision is much better with contacts. Spherical soft lenses are readily available for prescriptions as high as +/- 20.00 diopters.
The typical or average prescription is between +/- 1.00 to 4.00 diopters. For these cases, with minimal to no astigmatism, contact lens visual acuity is essentially equal to that of glasses, however, peripheral vision is always much better with contacts. When sports like soccer are considered, contact lenses are the best choice over any glasses, for safety reasons as well as vision.
With the proliferation of daily (single use) disposable soft contacts, it is now safe to wear lenses with swim goggles for water sports, including competitive swimming, snorkeling and scuba diving. The visual experience with contacts is far superior to that of prescription goggles and dive masks.
Prescriptions that require astigmatism power can be corrected well with soft astigmatism (toric) lenses. The results, however, can be mixed. Often, visual acuity is equal to that with glasses. Vision is rarely better than that with glasses and sometimes less clear than an accurate eyeglass prescription.
Astigmatic lenses have two power curves. Because the soft astigmatism lens is “floating” on the corneal surface, lens movement and rotation will intermittently compromise clarity and visual acuity if the two power curves are misaligned. Because these lenses are more complicated than single power spherical lenses, a diagnostic fitting usually requires more time to determine the most stable lens for optimum clarity.
While higher astigmatic prescriptions (between 3.50 to 8.00 diopters cylinder power) can be corrected with soft lenses, a better outcome is usually achieved with custom rigid gas permeable (RGP) Bitoric lenses. Vision correction with Bitoric RGP lenses is often significantly clearer than correction with glasses. These lenses are more complicated to fit. The final outcome with a successful prescription is very rewarding.
Multifocal (bifocal) contact lenses are available in both soft and RGP designs. The goal of these products is to provide both far and near vision for adults who would otherwise need to wear progressive multifocal glasses or have separate distance and near glasses.
The vision result with contacts in this category is mixed. Vision at best is reasonably good at far and near, however, never as clear as with glasses. While patients can be happy with these lenses, some compromise and understanding of product limitations is required.
The majority of patients tested with multifocal diagnostic lenses during the fitting process usually decide that either the distance or near vision is not clear enough. Conversely, a minority of patients are very happy to find that multifocal lenses do work for them. Alternatively, contact lens success for many can be accomplished with some form of monovision, where one eye has clear far vision and the other eye has clear near vision.