Strength
Reading glasses typically range from +0.25 to +2.50 diopters (the unit of measurement for eye prescriptions), though the average starting strength is usually around +0.75. In rare cases, reading glass strength can go up to +4.00.
“Tips for buying reading glasses online are similar to buying ready-made reading glasses at the drugstore: it’s a convenient option, but it’s not a good idea for everyone,” says Dr. Ravi Goel, clinical spokesperson for the American Academy of Ophthalmology. “If you have different prescription needs in each eye, astigmatism, high-power or more complex prescription needs, you should see an eye care professional for updated prescription eyewear.”
Reed seconds this, adding, “The wrong prescription can lead to headaches, eye strain or even nausea. If you do choose to buy online, we recommend selecting a lower power when deciding between two strengths, as this is generally a safer choice, and overly strong lenses tend to cause more discomfort than those that are slightly weaker.”
Goel notes that everyone over age 40 should see an ophthalmologist for a medical eye exam since that is the age when both presbyopia and potentially blinding eye diseases usually begin developing. Plus, not all eye diseases begin with noticeable symptoms.
Type of reading glasses
“There are four main types of reading glasses: single vision, bifocal, trifocal and progressive,” says Goel, defining them as:
Single-vision reading lenses are typically designed to correct just for near vision.
are typically designed to correct just for near vision. Bifocal lenses have a correction for reading on the bottom half of the lens and another for distance on the top.
have a correction for reading on the bottom half of the lens and another for distance on the top. Trifocal lenses have three sections: distance, intermediate and near vision. Reed says these can be particularly helpful for people over 50 experiencing reduced depth of focus.
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