Presbyopia, describes the condition where as part of normal aging, the eyes lose their ability to focus up close. This usually becomes noticeable around age 40. The muscles in the eye slowly lose their elasticity, which makes it difficult to focus at different distances. If you can focus, you usually cannot do it for long periods of time or without some eyestrain. Reading glasses can easily solve this.
Since much of our close work takes place at different distances, selecting the correct lens power requires some careful analysis. For a reading distance between 14-16 inches, following the reading glasses strength chart below will help you find the correct lens power for you. If you have a prescription from an eye care professional and are unsure of what lens power would be best for you, email your prescription to firstname.lastname@example.org for help.
If most of your reading is done at a computer then you need to establish how far you are from the computer screen, which can be a different distance depending on whether you use a laptop or a desktop computer. To determine the correct power for reading at computer distance, it is best to first determine your lens power at close (usually between 14 -16 inches) and then reduce that power by ½ which should give you the power you would need if your computer is approximately 18-20 inches away. The further you are from the screen, the less lens power you will need to see clearly.
Print this page out on your printer. You cannot use this chart by looking at your monitor due to size and resolution differences among computers. The chart should print out at 7.5 inches wide. To find the right lens power for you, read the chart at the customary reading distance of 14-16 inches. The first line you have difficulty reading is the suggested lens strength for you at that distance. To determine your correction for computer distance, refer to the directions above for a more detailed explanation.