By Dr Lee Mun Toong
As we get older, most of us need eyeglasses at least for reading. Already by the end of our 30s, the lens of the eye begins to lose resiliency and the capability to focus at a close distance. On average, this starts to cause some difficulty in seeing at close distances soon after the age of 40. Presbyopia or ‘aging eye’ affects almost everyone whether or not they have worn glasses when young. Presbyopia increases until the age of about 40-60.
Can presbyopia be corrected?
The flexibility of the eye’s inner lens cannot be restored, but the problem of presbyopia or ‘aging eye’ can be corrected by means of FemtoLasik® laser surgery through bringing monovision to the eyes. In this case, one eye is operated on to see far and the other one a short distance.
The elimination of presbyopia must be handled through the monovision solution, since if both eyes are operated to see at a close distance, distance vision suffers. If, on the other hand, both eyes are operated to see far, reading becomes unsuccessful. It takes a while for the brain to get used to monovision, but with time it adjusts to the new situation, since the brain learns to use only the leading eye for seeing distance. The adjustment period for monovision varies from one individual to another – from a few days to a few months.
Since ‘aging eye’ undergoes a gradual increase until about the age of 40, it is possible that the eye used for reading should be corrected on several occasions as time goes on. The required close-vision strength should be increased at the time, quite like stronger reading glasses should otherwise be obtained.
Single binocular vision does not disappear as a result of monovision, since it is not based on sight precision. The eye focused on a short-distance object is still capable of seeing far, though not sharply. For this reason, single binocular vision is possible. At first, reading may feel troublesome, but the brain soon learns to use the eye for reading for that particular purpose. Monovision is an excellent solution to the problem of ‘aging eye’, or presbyopia.
What sort of results have been obtained from monovision?
The majority of those who have chosen the monovision solution are highly satisfied with the visual proficiency achieved. They should, however, remember that presbyopia (‘aging eye’) does not disappear with surgery or eyeglass correction – nor can the vision of a very young person ever be regained.
Monovision represents a compromise, just as varifocals do. It is not possible to see all distances and in all circumstances well. It is a good idea to discuss with a physician what the best solution is, taking one’s work and hobbies into account. It is also quite possible to repair only your distance vision and use reading glasses as required.
It is highly individual how long getting used to the monovision solution takes. With some, only a few days are required; with others a few months may be needed before they are satisfied with the new circumstances. The speed of getting accustomed to the situation is also greatly affected by the amount of lens power required.