Bifocal Contact Lenses for Near and Far sight (Presbyopia)
As with bifocal glasses, bifocal
(and multi-focal) contact lenses are used to treat patients with problems
of both near sightedness and far sightedness, a condition known as presbyopia.
Bifocal contact lenses can be difficult to fit, and may require several lens
changes before the right one is found. However, many patients find them worth
Bifocal contact lenses are available as daily disposable, frequent replacement,
multi-package disposable, rigid gas permeable, soft, and even toric (to
treat astigmatism) contact lenses. There are two basic designs for bifocal
contact lenses and within those designs are varieties of Rigid Gas Permeable
and soft contact lenses.
- Designed to allow the patient to see both near and far at the same
time. Requires patient to choose which image to focus on.
- Near and far
refractions are superimposed.
- Lenses do not use a prism.
- Uses an aspheric design.
- Have small optic zone diameters. The patient alternates between zones
- Use a prism to stop lens rotation.
RIGID GAS PERMEABLE BIFOCAL CONTACT LENSES
- Have steep vision
- Corneal apex, lower lid position and pupil size along
with lens performance, must be considered when fitting the lens
• Allow patient to see near and far simultaneously, requiring patient
to choose which image to focus on
• Easier to fit than alternating
- Alternating RGP
• Near, intermediate, and distant powers are arranged in concentric rings
• Pupil size dictates zone size
SOFT BIFOCAL CONTACT LENSES
- Most preferred type in soft bifocal contact lenses
- Allows patient
to see near and far images simultaneously, requiring patient to choose
which image to focus on
- Anterior Aspheric Surface
• Ideal for patients who require better vision in bright light
• Posterior Aspheric Surface
• Ideal for patients who require better near vision in bright light
Soft Contact Lenses
• Can be near centered or far centered
• Pupil size important in near centered lenses
Speak to your doctor at your next exam. One of these choices may be right