Presbyopia is a condition in which the eye loses its ability to focus on near objects. It affects most people in their 40s and, in some cases, presbyopia surgery may be used to treat the problem. There are a number of different operations available, some of which alter the shape of the eyeball and others which insert a type of lens. Sometimes people can learn to use what is called monovision, where one eye is adapted for near vision, leaving the other eye for viewing distant objects. None of the techniques offer a perfect solution, and for some people reading glasses or contact lenses may be preferred, but presbyopia surgery, while not without risks, can provide an acceptable range of vision for certain individuals.
One of the main methods of presbyopia surgery uses what is called laser vision correction, or LASIK, to correct one eye, normally the dominant one, for distance vision, while the other eye is left slightly near-sighted, for reading. The dominant eye is the one which the brain favors, in the same way as people are naturally left- or right-handed. Not everyone can learn to use monovision, and it is recommended that people try monovision contact lenses before committing to surgery. Perfect vision is not guaranteed following LASIK, but people usually need to use glasses or contact lenses less than they did before.
People with presbyopia and sight that is otherwise normal may be suitable for an operation known as conductive keratoplasty. Instead of lasers, radio waves are used to shrink areas around the edges of the cornea, the transparent covering of the eyeball. This reshapes the eyeball, making it curve more steeply in the middle and effectively lengthening it. The eye becomes more near-sighted, so it can be used for close work such as reading, leaving the dominant eye for distance vision. Again, it is important to determine before surgery that the person is able to function using monovision.
These two methods of presbyopia surgery normally require only a few hours' stay in a clinic. There may be mild discomfort or blurred vision immediately after the operation, and it might be necessary to wear protective dark glasses, to avoid getting water or other substances in the eye, and to rest for a day or so. Any surgery on the other eye is generally carried out at least a week after the first procedure. Most people experience a satisfactory outcome following presbyopia surgery but, very rarely, complications such as sight loss can occur.
In addition to these types of presbyopia surgery, there are a number of other treatments which are not widely available or are currently in trial. They include the use of gas bubbles to reshape the eye, insertion of artificial lenses similar to those used in cataract surgery, corneal implants and the creation of multiple zones of focus on the front of the eye. An ophthalmologist will be able to advise which, if any, of the presbyopia eye surgery techniques is appropriate.