For people who want to buy a pair of prescription eyeglasses for the first time, the first step is to get the eyes examined. During an eye test, the eye doctor will determine the patient’s eye prescription. Using this information, the exact powers of the two lenses can be prescribed. This examination or measurement is really critical for every person who relies on Rx eyeglasses for visual aid. It is estimated that over one half of the world’s population is affected by different types of eye condition. And these patients suffer from weak eyesight and have difficulty in seeing objects clearly without external help. Another fact is that visual refractive errors like myopia and hyperopia and presbyopia can occur in different degrees of severity. Taking myopia as an example, some people have a -2.00 prescription, while some others’ prescription is even as high as -4.00. This difference in severity makes a comprehensive eye exam very important. In some cases, it is necessary to use strong glasses.
Strong eyeglasses mean spectacles that are used by people with a strong prescription. The reason is that their visual problems are quite serious or severe. Eyeglass lenses with different powers can be prescribed according to patients’ specific prescriptions. Most people will get satisfied with lenses with ordinary powers. But those strong lenses are the exact solution for some people with a heavy prescription. To some extent, strong glasses are necessity for a large group of people, because most Rx eyewear users’ eyesight continues deteriorating until a certain age. This is why most young patients especially those school students need to get their eyes re-examined and eyeglasses re-prescribed at a certain interval.
Traditionally, strong glasses occurred with always thick lenses. This is because at that time only glass and regular plastics could be used to make eyeglass lenses. The lens thickness and the strength of the lens were in proportional. Due to this limitation, patients with a heavy prescription had to take glasses with quite thick lenses and tolerated an ugly look. Fortunately, this situation has been largely changed. New lens materials including high index plastics allow lenses with a strong prescription to be as thin as regular lenses. This is really a great gift for patients with an extreme eye condition.