You may have seen many people wearing glasses for nearsightedness after the age of 40. They have to wear glasses while reading, as their near vision becomes blurred. Our eyesight changes as we age, it is a common phenomenon. Most of us are aware of it, but we do not know that it is called Presbyopia technically, by ophthalmologists.
Presbyopia sets in with growing age. The crystalline lens in the eye loses its elasticity and ability to focus distinctly on the nearby objects. For years the corrective method used to treat presbyopia was with bifocal glasses.But with the technique of monovision, it has been possible to restore your youthful vision and enjoy reading newspaper, mobile phone number, without wearing glasses. But unfortunately monovision may not be suitable for everyone, there can be monvision problems. Before elaborating further, let us know what monovion is and how it works.
What Is Monovision Correction?
The technique of monovision involves wearing near vision contact lens in one eye and wearing distant vision contact lens in another eye (if needed). We all have a dominant and non dominant eye, just as we have a dominant hand or a dominant leg.The ophthalmologist determines which eye is dominant. Usually it is the dominant eye through which we are able to see distant objects more clearly than the non dominant eye. In such as case if refractory error for near vision is corrected in the non dominant eye, our vision for seeing distant objects will not be much affected.
If needed, the contact lens with different prescription can be worn for distant vision in the dominant eye. The brain gradually adapts to this arrangement and evaluates the visual image when we focus the dominant eye for seeing distant object and focus the non dominant eye to see the nearby objects. It may take 1 to 2 weeks to adjust, after wearing contact lens. In some cases it may take more time. The technique is given its name monovision (mono means one), because each eye has been intended for a specific type of vision (near or distance).
There are several approaches for monovision technique; the easiest method is to use special contact lenses. The other method is LASIK eye surgery. But before opting for laser eye approach, you will always have to try contact eye lenses. This is because if you are not happy with monovision, you can always change back to bifocal. But with laser eye surgery, the changes are permanent.
Monovision Technique Problems
Monovision can be a great option as compared to bifocal glasses for people having presbyopia. However there are several potential problems associated with it such as, it may interfere synchronous working of both the eyes for achieving proper focus, range of vision. There may also be a loss of depth perception. Since each eye has independent function, it may take time for the eyes to start working together. During this interval, a person may experience some trouble in depth perception as well as vision clarity.
Some people may not adapt to monovision technique. They may find difficulty in seeing objects located intermediately (not too far nor too near). This means they may find difficulty in focusing objects between 1feet and 16 feet. The objects may look blurred. For this reason, they may have to strain their eyes. Constant straining of eyes may lead to frontal headaches.
Similarly, monovision may cause difficulty in viewing distance objects sharply. This is because only one eye, the dominant eye, is fitted with distant vision lens, and the other eye is not helping in accommodation. This causes disparity and discomfort in your judgment of the distance object, especially during night. It may be great cause of concern for drivers, driving their cars at night. The glare from the headlight may further aggravate the problem.
Alternative To Monovision Problems
Even with all the problems of monovision, many people try it as an alternative to the bifocal glasses. This is because monovision is less expensive as compared to bifocal or multifocal lenses. With regular modifications, nowadays new modified monovision lenses are available as an alternative to the old version of single vision near lens. It has been found to be more effective with lesser problems.