How can a person determine what type of lens he may require? | Goggles4u Eyeglasses Blog
Food for thought, does your eyesight seems blurry while reading a book, newspaper or driving? Then it’s time for you to buy prescription glasses. But for someone who has never worn glasses can be faced with a dilemma to what type of lens he may require?
The first thing that you should do is get your eyesight examined from a certified Optician. He will examine your eyesight whether you need single vision glasses either for reading purpose or for distance purpose depending upon your power of eyesight and the lenses you require for correct vision. They are usually called reading glasses or distance glasses.
To properly determine the power of your lenses, you would have to take a Diopter Test in which you have to read lines of words, ranging in sizes from small to large. Each line will have a corresponding prescription. You would be asked to wear different lenses of different power you require for the best vision.
Lens for Reading or Distance Glasses
If you have trouble while reading small letters or words then you need reading glasses. Single vision lens are used with lens power for example +1.00, +1.25, +1.50 and +1.75. Single vision lens may also be used for distance eye sight problem with different lens power. You can try several pairs for correct vision that have stronger and weaker prescriptions. Sometimes you may even have different power lens for both right and left eye.
Those people who read newspapers, book or spend a lot of time looking at their computer screens may also need reading glasses. However things would get blurry if you look up through your reading lens. Different type of lens must then be used.
People usually start out the reading glasses which have single vision lens either for reading or distance. They then switch over to Bifocal or Progressive lens.
Different Types of Lens
Bifocal lens are basically for those people who are at the age of 40 or above. The upper part of the Bifocal lens is generally used for distance vision, while the lower segment is used for near vision/reading. This would be an ideal choice for those who wear glasses all the time for near sight or distance vision problems having two lens power where as trifocal lens contain three lens power. Bifocal and Trifocal lens glasses are for those people who wear glasses constantly.
Glasses which have Progressive lens do change in power top half of the lens to the bottom. These are usually prescribed for adults over the age of 40 or for children or young adults who have focusing problems causing eye strain while reading.
Bifocal or Multi Focal lenses also control myopia by reducing focusing power which occurs while reading. The lower part of the Bifocal lens has the power to correct your near vision while the rest of the lens usually is for your distance vision.
Whereas Trifocal Lens in glasses has three points of focus — usually for distance, intermediate and near vision.
The intermediate segment in trifocal lenses is directly above the near segment which is used to view objects at arm's length. An example for an intermediate zone would be a computer.
Myopia is called for short sight problems and Hyperopia for long sight problems. Bifocal or Trifocal lenses would be best for people suffering from both of these problems of any age while those people having just the short sight or long sight problems can opt for single vision lens depending upon the lens power.
Long Sight problem can be correct by using the - power lens and Short Sight problem can be corrected by using the + power lens. Bifocal or Trifocal can have both + and – power lenses.