Presbyopia is a condition of the eyes in which we lose the ability to see objects close to our eyes clearly. This condition appears around the age of 40 years and progresses as we age. It may appear well before or after 40 years of age depending on other coexisting refractive errors.
Presbyopia is corrected with glasses with plus (convex) lenses which help focus the image of near objects on the retina of the eyes.
It is important to understand here that the power of glasses for presbyopia increases gradually as we grow older. For example, if it is +0.75 Diopter at the age of 40 years, it would progress with age and could reach up to +3.00 Diopter around the age of 60 years.
There are many people who are not comfortable with their reading glasses. They have eye strain, headache and inability to see anything clearly at close distance especially after working on computer, reading or writing or doing any near-work for that matter for some time.
There are three categories of patients with such complaints:
1. If your reading glasses are old and you don’t see well with them any more:
Considering the expected change of power of reading glasses with aging, it’s probably the time to see your optometrist and get a new prescription. Don’t worry about this ‘worsening’ of eye sight. It’s all natural and is part of aging.
2. If your reading glasses are new but you don’t see well and/or have eye strain while using them:
This could simply be because the glasses were not made as per the prescription – either the power of lenses is not correct or the IPD (interpupillary distance) of the glasses does not match with your IPD. IPD is the distance between the pupils of your eyes. This distance varies from person to person and is recorded by the optometrist before ordering glasses.
Another possibility is that you may be having some other eye disease causing poor vision or a medication you are taking, could cause it. In any case, you will need to see your ophthalmologist to identify the cause.
3. If you are using progressive lenses:
Progressive lenses are the ones in which the power for near vision in the lower segment of the lens progressively changes to power for the distance vision in the upper segment. While looking at an object, tilting your head up or down will determine through which area of the lens you are looking through.
Some people are not aware of their head tilt while they are reading or working on computer and are subconsciously looking through the middle portion of the lens where the power is less. This causes eye strain, discomfort, headache and inability to concentrate.
The solution of this problem is very simple. Just lift your head till you see the near object (book, phone, computer screen etc) clearly. You should try to maintain this position of the head while working or reading.
Pushing the glasses up on your nose also aligns the visual axis with the lower part of the progressive glasses helping you see well.
If you have any questions regarding your reading glasses, write in the comments below. I will try to answer all of them.