What strength reading glasses is correct for you?

What do the reading glasses strength numbers mean?

The strength of reading glasses lenses is indicated by numbers, which are referred to as "diopters". These numbers act as a measurement of the magnification level of the lens. They are usually measured in increments of .50 diopters, to distinguish between stronger and weaker reading correction.

If you’d usually need reading glasses with a strength of around +3.00, that means you require strong reading correction. If you wear reading glasses with +1.50 strength or lower, this means you only require minor vision correction.

Reading glasses strengths lowest to highest

Reading glasses strengths usually range from the lowest strength of +0.25 diopters, to high-strength ones that can exceed +2.50 diopters. In rare cases, lenses that go up to +4.00 diopters are available.

The GLAS core collection offers reading glasses with strengths starting at +1.00, going all the way up to +4.00.

Our other limited collections and colours offer the same spectrum of strengths but stop at +3.00.

The most common reading glasses strengths

Most people who need reading glasses typically require a strength between +1.00 and +2.50 diopters. However, this is just a general guideline, and the exact strength of reading glasses needed can vary based on several factors, including age, and the individual's eye health.

For example, when you first require reading glasses, you will most likely not need a very powerful strength lens. Presbyopia usually begins as a mild vision problem and gradually worsens with age. While some people may eventually need reading glasses with a strength of +3.50 - +4.00 diopters, this is relatively uncommon.

Why is it important to have the correct reading glasses strength?

It is important to ensure that you’re using the correct reading glasses strength for you.

Opting for reading glasses with an incorrect strength can result in undesirable symptoms such as:

• Headaches

• Eye fatigue and strain

• Blurred or fuzzy text when reading

Wearing the correct reading glasses also has many future advantages beyond just improving your vision. If you continue to strain your eyes over time, your eyesight may deteriorate even further. Wearing reading glasses at an early stage reduces strain on your eyes, helping to keep your eyesight strong for a longer period of time.

Ways to know which strength reading glasses you need

If you want to know what reading glasses strength is best for you, there are a few ways you can start by testing your strength easily at home.

Estimate reading glasses strength by age

In terms of normal age-related vision changes, we humans are relatively alike. One way you can estimate your reading glasses strength is by considering your age. Usually, the following applies;

• Age < 35 years: 0

• Age 40 years: +1.0

• Age 45 years: +1.5

• Age 50 years: +2.0

• Age 55 years: +2.5

• Age 60 years: +3.0

Test your reading glasses strength online

You can also test your reading glasses strength online in just three steps, with this easy method.

Step 1: Look at the chart below with your screen about 40 centimetres from your face.

Step 2: Remove any corrective lenses, and read the chart from top to bottom. You may have to proceed down multiple rows until you can read a line perfectly. Cover one eye at a time, and repeat the process.

Step 3: Take note of the first row that you can read clearly. This is likely to be very close to the strength of reading glasses that is right for you.