Presbyopia

Presbyopia is a loss of the eye’s ability to focus on near objects. This phenomenon usually begins after 40 and is part of the normal ageing process. It occurs as result of the natural deterioration of the muscles due to ageing. The eye has a muscle, called the ciliary muscle, which focuses the lens so that near objects can be seen clearly. The ciliary muscle, like the rest of the muscles in the body, loses elasticity with the passing of time and, as a result, the ability of the lens to focus and see close objects well.

Three different techniques exist for the treatment of presbyopia using refractive surgery:

Monovision:
Using the excimer laser, the refractive error is completely corrected in the dominant eye, but in the other eye the refractive error is slightly under-corrected. In other words, the non-dominant eye is left slightly myopic and therefore focussed for near vision. Before proceeding with this treatment an adaptation test is carried out.

Presby LASIK:
By using techniques to modify corneal asphericity it is possible to increase the depth of focus thereby allowing the eye to focus for both near and far vision. Other techniques are based on creating a bifocal or multifocal cornea. Currently, alterations of up to +1.5 dioptres can be achieved.

Multifocal and accommodating lens implants:
This treatment is appropriate for patients who are going to have a cataract operation but, for whatever reason, are not suitable for treatment with the laser. The lens implants can be either multifocal in shape or may be lenses that shift inside the eye thereby adjusting focus by using the natural accommodation mechanism.