So, what is presbyopia? It's a vision issue characterized by inability to focus on objects. Nobody is excused from presbyopia for it is a vision incapacity that normally occurs during old age around ages 40s-50s. If you are in your 40s and need to move the book further to be able to read it, then consider yourself as an official Presbyopes' candidate.Accordingly, when a person reaches 40s, the ciliary muscles of crystalline lens looses its elasticity. When near object is viewed, ciliary muscles contracts getting the front and back surface of crystalline lens to bulge outward to be able to focus on near objects. The term is called eye accommodation- the process of eye adjustment to be focusing on objects at a distance.
There are two designs of bifocal contact lenses including alternating vision and simultaneous vision. Alternating vision is the sort of bifocal contact lens that has two powers. Both powers are alternately viewed by the pupil in upward and downward axis. With old versions alternating bifocals, these two different powers can be obviously noticed when the contact lenses are closely viewed. But then , with more enhanced bifocals nowadays, the distinctions between two powers grown to be unseen because of its more advanced natural model. Alternating vision lenses are based on the lower eyelid to hold the lenses constantly in place with near-correction power found in the lower part of the lens. Many of alternate vision bifocals are lenses made of RGP. They are smaller compared to the much softer regular ones.
Simultaneous bifocals, in contrast, are vision contact lenses that are design for both near and distant object at the same time. With simultaneous bifocals, your eye pupil can see the upward and downward directions at the same time. The eyes will automatically choose the power preference based on range. Simultaneous bifocals are classified into two designs known as Concentric Ring Design and Aspheric Design. With Concentric Ring, the prescription is incorporated in the central point surrounded by power rings. Location of power distance may vary accordingly in terms of characteristics. Gas Permeable bifocal lenses are for distance-power and the power is located in the center. On the other hand, soft bifocals are for near-power where power is located in the middle of the lens as well. With Aspheric Multi-focal Contact Lenses, also known as progressive contact lenses, the power is dispersed throughout the lens. Your eyes will then adapt to the matched prescription, either for near-power or distant-power.
Presbyopes or people with Presbyope, could now choose for various selections of bifocal contact lenses with regards to to their tastes of characteristics, wear schedule and life span . In terms of characteristics, bifocal contact lenses can be rigid gas permeable or in soft forms. They are not just corrective but could be use for fashion functions. Cosmetic bifocal are in various colors. When it comes to wear schedule, they can be daily, weekly of yearly.
Since presbyopia is anticipated in old age, it appeared that we have no other option but to use bifocal contact lenses in our old age. I believe no one wants to deprive himself/herself from reading by not using bifocals.
