Bifocal Contact Lenses
Bifocal contact lenses are special types of presbyopia contact lenses. They can be used for patient with presbyopia for correction of both near and far vision.
How bifocal works
Certain designs should be added to the contact lens to enable the patient to see clearly for near and far and these designs are:
1- Translating design
This design of bifocal lenses is also called segmented design or lens because it is divided into two segments. The upper segment is usually designed for far vision while the lower segment is designed for near vision.
When the patient is looking downward or working for near task, his eyes will move downward while the contact lens will move slightly upward and in this case the lower part of the contact lens or the near part will come infront the pupil and allows the patient to have near vision.
When the patient is looking for far distance like in driving, his eye will move to its position from the bottom to the top part and the contact lens will move from up to down, allowing the far distance to come infront the pupil and the patient can see for far.
It is also called alternating design because the pupil will alternate its position.