Since the invention of the first pair of Varilux progressive glasses with a modern design in 1953, superior progressive eyeglasses have gained much popularity among the public. This is well-founded due to their incomparable advantages over bifocal and trifocal glasses. It is absolutely understandable for many customers to pursue these benefits. Many of them choose to switch from traditional bifocal or trifocal lenses into progressive ones. In recent years, there is also another phenomenon that many customers resort to online stores for progressive glasses, even if they involve sophisticated factors. The most convincing reason of such a practice is the higher prices of progressive glasses. Buying progressive lens eye glasses online is the most acceptable for some individuals. They are willing to spend more time in the interacting with the salesmen, in favor of considerable savings. But to some extent, those online progressive glasses are probably less competent in offering individual vision correction.
These disadvantageous aspects of online progressive eyeglasses are closely linked with those natural shortcomings of progressive lenses. Without the in-person check from an optician, these shortcomings will likely be magnified. The first problem is visual distortion. Progressive lenses offering the power progression may create regions of aberration away from the optic axis, causing poor visual resolution. This can be easily explained that a progressive lens combines a range of powers together in a single surface. In such a case, geometric distortions will occur in the visual field. This kind of distortion will even increase with a high addition power. In a worst case, such distortions may totally outweigh those recognized benefits of using progressive lenses. Nowadays, most manufacturers claim that they can reach an acceptance rate between 90% and 98%. However, buying progressive lens eye glasses online may increase such a risk.
Another factor is lens fitting. Progressive lenses must be carefully fitted according to the wearers’ pupil center of a distance-viewing reference position. Such a correct position is essential to guarantee normal corrected vision at all distances. Without such a delicate fitting, potential problems include narrow fields of view, clear vision in one eye only, on-axis blur and the need to adopt uncomfortable head positions. Purchasing progressive glasses online makes such a personal fitting unavailable. Additional lens fitting is always needed after receiving a progressive pair. This means extra cost at the customer’s side. All in all, progressive lens eye glasses online should not be the regular choice for most customers.
