Contact Lenses and Reading GlassesIf you wear contact lenses for distance vision, a pair of reading glasses can easily be slipped on for viewing near objects and for reading. However, you may find it difficult to reach for your reading glasses while wearing your contact lenses. After all, you are probably wearing contact lenses in the first place because you don't enjoy wearing eyeglasses.
This option may not sound appealing to you, but this is generally the best way to obtain the clearest vision at distance, intermediate or near. The contact lenses are prescribed to correct your distance vision in full. Then single-vision intermediate, arms-length eyeglasses or single-vision near reading glasses are worn for items at a closer range.
- PROS: Although not the most convenient method of vision correction, this method does deliver the clearest, sharpest vision for every task. People who have certain occupations that require precise vision usually do better wearing this method of vision correction. Athletes tend to enjoy this method to maximize their distance vision.
- CONS: You must put on and take off your reading glasses every time you wish to see clearly at distance. In effect, you must always have your reading glasses handy.
Monovision Contact LensesIn monovision, one contact lens is worn for distance vision and another one is worn for near. The distance contact lens is usually worn in the dominant eye. We all have a dominant eye that we primarily use when looking at distance objects. As a result, a near-focused contact lens in the non-dominate eye does not seem to create difficulty in adapting to this method of vision correction.
- PROS: While it sounds very strange, many monovision contact lens patients adjust more quickly than to other types of presbyopic contact lenses. Near vision seems to be slightly clearer with monovision because each eye is fit with single vision lens strength. Also, if finding a comfortable contact lens is difficult for you, your doctor has almost an unlimited choice of lens materials, sizes and shapes because monovision is just a power adjustment, rather than a specific brand of contact lens.
- CONS: Some people notice slightly decreased distance or driving vision, especially at night, with monovision. Depth perception is also slightly decreased while wearing monovision, which may be a significant problem for people who enjoy sports, such as golf and tennis. Also, professional or leisure pilots cannot wear monovision as it may cause a certain area of vision to be slightly blurred.
Bifocal or Multifocal Contact LensesBifocal or multifocal contact lenses aim to create more natural vision, as both eyes are corrected for distance vision as well as for near vision. Multifocal lenses are available in several different types, including rigid gas permeable, hybrid hard/soft and regular soft contact lenses. Depending on the manufacturer, they all work a little differently.
Some of the rigid lenses are designed more like a lined flat-top bifocal eyeglass lens and move around on your eye. When you look down to read, they move up slightly so your line of sight is lined up with the near segment. Other lenses are considered aspheric lens designs and do not usually move around on the eye. Aspheric designs gradually and smoothly increase in power from the center to the periphery of the lens. Some of these lenses have near vision power in the middle of the lens and distance power in the periphery, or vice versa. These contact lenses work more like a no-line progressive spectacle lens and are sometimes dependent on the size of your pupils.
Other lenses may be concentrically designed. Concentric designs have alternating rings of distance and near power. These are similar to having two lenses, one distance and one near, smashed together.
It will take some time for your eyes to adjust to bifocal contact lenses. After a little while, your eyes will learn to differentiate between the different prescriptions, and will begin to use the proper prescription for the proper distance.
- PROS: Multifocal lenses minimally decrease depth perception, if at all. If fit successfully, you will not have to wear eyeglasses over your contact lenses for most of your daily activities.
- CONS: Some multifocal lens patients complain of blurred vision while doing certain tasks. If distance vision is extremely clear, then near vision sometimes suffers. If near vision is clear, distance or intermediate vision may be less than expected. Most eye doctors interview their patients to see which task is most important and specific to them and aim to provide better vision for that task. Some people complain of ghost images or doubling of images at certain times, usually when wearing multifocal contacts for the first time. Although this is part of the adaptation process, it does bother some people to the point where they discontinue wearing them. Contrast sensitivity is sometimes a problem while wearing multifocal lenses. Some people will be able to read the 20/20 line, but say it doesn’t appear "crisp."
What You Should KnowSome eye doctors fit a mixture of the above methods, depending on a patient's needs. Fitting presbyopic contact lenses depends on many factors including your flexibility, lifestyle, prescription and your eye’s anatomy and physiology. Optometric physicians and ophthalmologists who fit contact lenses quickly learn that one lens type does not work for everyone. Fitting contact lenses to correct presbyopia requires a little science and a little art.
Gupta, N, SA Naroo and JS Wolffsohn. "Visual comparison of multifocal contact lens to monovision." Optometry and Visual Science, Feb 2009.