Present now, hi-tech progressive lens glasses are gaining popularity. The background is that presbyopia makes it a necessity to wear multifocal prescription eyeglasses. It can be quite bothersome for the majority of presbyopic patients to make switches between two pairs of prescription glasses for nearsightedness and presbyopia respectively. Most of those individuals would like to use reading glasses only in office or at home during long terms of materials reading. When they are forced to change focusing ranges, from the near to the distant or vice versa, two different pairs of prescription glasses will lead to solely inconvenience. The great US founder Benjamin Franklin first invented bifocal eyeglasses which were used to eliminate such an inconvenience. A pair of bifocal spectacles can offer both near and distance corrected vision. It is no longer needed to change different pairs.
With the increasingly popular computer usage, a lot of individuals suffer from Computer Vision Syndrome (CVS). This is because a computer screen usually sits within the intermediate vision range, different from either near vision zone or distance vision zone. Keeping a separate pair of computer glasses usually causes a similar inconvenience like reading glasses. Modern technologies have made trifocal eyeglasses a reality. This kind of prescription eyeglasses can offer corrected eyesight at three distances: the near, the distance as well the intermediate. This functionality can be obviously reflected by its name. Trifocal glasses make a further step by offering special “computer vision”.
Bifocal and trifocal eyeglasses seem like advanced enough in providing clear vision at multiple ranges. They can “kill two or three birds with a single stone”. However, they are not advanced enough among the family of multifocal eyeglasses. There are still progressive lens glasses. In a comparable way, bifocal and trifocal eyeglasses have certain disadvantages over progressive glasses. It is equally important to emphasize advantages of progressive glasses. The first aspect is associated with eyeglass appearance. Using bifocal or trifocal eyeglasses, there will be noticeably a visible line or two lines on the lens. These lines are functionally used to set apart different visual zones. However, this also enables other individuals to know that a wearer needs reading glasses. It is really disappointing in either appearance or self-esteem. Progressive glasses never cause these concerns. No visible line exists. More critically, conventionally bifocal or trifocal glasses usually cause images to “jump” because they have separate vision zones. Progressive lens glasses can offer smooth and seamless lowers transition.
