Presbyopia is an eye disorder that normally sets in between the ages of 40-50. A lot many theories have been suggested to delineate its proper cause. However, the most convincing theory is that the eye lens loses its elasticity over time, and this in turn results in the loss of accommodation power of the lens. Consequently, the lens is unable to focus on nearby objects, and hence the patient's near vision is rather blurry. Presbyopia affects everyone at a certain age and it is not routinely curable. The loss of accommodation power can be compensated for through LASIK surgery by producing what's called "monovision". Normally, people possess binocular vision. That is, both eyes work together equally while viewing an object. On the other hand, in case of monovision, one eye is corrected for near vision and the other is corrected for distant vision. LASIK surgeons make use of this technique to counter presbyopia. LASIK can be a viable option for producing monovision. However, there is a caveat. Monovision is not appropriate for everyone. Furthermore, monovision may also interfere with depth perception. That is, the patient may not be able to perceive the accurate distance of any object, since accurate 3D perception requires input from both eyes. Therefore, it is recommended that the patient first uses contact lenses to produce monovision, in order to ensure that he or she can adapt to the change. Apart from surgery, a patient may use prescription glasses (bifocal or progressive) to compensate for the loss of power of accommodation. Intraocular lens implant is another viable alternative to counter presbyopia. In essence, the natural lens is replaced with a new lens to achieve accurate refraction. Another interesting aspect is that presbyopia may not have a major affect on people with myopia. In general, a myopic does not have trouble reading without glasses. Thus a myopic often possesses perfect reading vision, without any visual aid, even in the old age and even after presbyopia sets in. |
