Your reading glasses lens strength is determined by a number of factors such as:
1) YOUR AGE
2) YOUR READING DISTANCE
3) WHETHER OR NOT YOU WEAR OR NEED PRESCRIPTION EYEGLASSES FOR OTHER DISTANCES.
Fortunately, it is easy to estimate your reading glasses strength.
The main determining factor of lens power is the onset of Presbyopia, therefore we are able to use our age as a starting point to find our lens power. Presbyopia is the normal loss of near focusing ability and is an age-related process that occurs sometime after 40. The process can be described as a gradual loss of flexibility of the natural lens and surrounding muscle fibres inside the eye. With less elasticity, it gets difficult for the eyes to focus on close objects. This is why we may start having difficulty seeing small print clearly, including text messages on our phones, menus and general reading.
STEP 1: Use your age as a starting point
+ 40 years old start with +1.00
+ 45 years old +1.50
+ 50 years old +2.00
+ 60 years old +2.50 to +3.00
STEP 2: Take the Eye Test
Print out our eye test chart, hold the chart around 35 – 40 cms (traditional book reading distance) from you. The first line you have difficulty reading is your suggested lens strength at that reading distance. Each diopter power is uniquely colour coded for easy identification. Once you have determined what strength you will need, for example 3.00 is red, if you need power 3.00, you will select red when you visit Clicks to make your purchase.
As a rule of thumb, when two reading glass powers seem equally suitable, choose the lens with the lower diopter power. We recommend that you have an annual professional eye examination.
STEP 3: Adjust for your Reading Distance.
The distance at which you intend to read influences the reading power you will need. Traditionally the distance for reading material is between 35 – 40 cms and computer distance ranges from 45 – 50 cms. If you would like to use reading glasses at your computer, it is suggested to find your correct lens power for the traditional reading distance. From here you can reduce the lens strength by around half. This is an estimated power you would need for your computer, however, this power may need slight changing based on the distance of your computer screen.
STEP 4: Adjust for prescription eyeglasses for other distances.
If you’ve never needed prescription glasses for vision problems such as nearsightedness, farsightedness and/or astigmatism, it is likely that using our non-prescription reading glasses will be sufficient for managing presbyopia. However, If you already have a prescription from an eye care professional, ask them what lens strength of reading glasses they would recommend.