Eyeglasses and Sunglasses Prescription Type
- Single Vision
Single vision is the most common prescription type which seeks to correct a single field of vision, with one prescription focused across the entire lens. If you suffer from near-sightedness, known as myopia, or long-sightedness, known as hyperopia, then you are likely to require a single vision prescription if you are under the age of 40. If you need a prescription for glasses to wear while reading or driving, then you likely be given single vision glasses to correct your eyesight. If your single vision lenses are for near-sightedness then they will typically be thicker at the edge, whereas for far-sightedness they are thickest at the centre.
Progressive prescriptions correct your vision at different distances and maintain the appearance of a single element the way that single vision lenses do. Unlike bifocals with lines, there are no visible lines in a progressive lens. Progressive lens are typically prescribed if you suffer from presbyopia, where your vision has lost its near-eyesight. The progressive lenses can also be known as ‘multifocal lenses’, as it will allow you to see at all distances. The progressive lenses have a gradient, or progressive, prescription in them, making certain parts of the lens stronger than others. This type of prescription is most common with those over 40 who suffer from presbyopia, or amongst children who have an increasing level of myopia or nearsightedness.
- Bifocal with Line
Bifocal lenses have two different prescriptions that are separated by a visible line which will be placed according to the needs of your vision. One part of the lens will have the prescription suited to distance, while the lower part will focus on correcting near vision. The lens segments will depend on the correction needed for your vision, with half-moon, round, ribbon and e-style segments being the most common for near-vision correction. Having bifocal lenses means that you only need to have one pair of glasses, instead of switching between two pairs of glasses depending on what are you doing during the day.
As you get older, the lenses in your eyes become less flexible which makes it increasingly difficult to focus on things that are close to you, in particular, words on a page. This is known as presbyopia, and your daily vision can be improved with a readers prescription. If the text appears blurry to you while reading, you struggle to read in dull light, or if you suffer from headaches or sore eyes while reading, then getting a readers prescription may be necessary. Readers are measured in diopters, with the lowest strength at 1.00 diopters, going up in factors of .25 with a maximum strength of 4.00 diopters.
- Non-Prescription Lenses
Non-prescription glasses are lenses without any sort of correction powers within them. If you have no issues with your vision but want to wear glasses for fashion or aesthetic reasons, then you should opt for the non-prescription choice. Non-prescription glasses have ‘piano’ lenses, which offer your eyes a level of protection against the environment and UV rays. Non-prescription glasses are perfectly safe to wear without causing any long-term damage to your vision. Most of the sunglasses that you find in your favourite shops will be non-prescription glasses. Buying non-prescription glasses is a more streamline