Distance or Bifocal Correction?
Here at Rapid Eyewear we've been manufacturing prescription sports sunglasses for some years, with many thousands of happy customers worldwide who came to us for a cost effective and reliable service. The question we get asked most has to be, should I go for distance or bifocal correction?
Distance And Bifocal Correction Explained
If you are 'short sighted' (sometimes referred to as 'myopia'), you need lenses that correct your ability to see objects at distance, whilst your near vision is okay. On the other hand, if you're 'long sighted', you need correction for close-up vision, but looking at distant objects is not a problem. In reality, many people need correction for both their long and short sight.
Few people have absolutely perfect short or long sight, but whether you need to correct one or both really depends on the activity you want to use the sunglasses for, and also the extent of the correction. By way of example, if you only want to use the sunglasses for rifle shooting and your reading correction requirement is very small, you would probably be better going for distance correction only since the most critical application is to see a distant target. You won't need bifocals unless you are so long sighted that everything close to you is very blurred, to the extent that you can't even load the gun without them. Another example would be cycling; if you can read well without glasses but find cars ahead look blurred, you only need distance correction; if you have a GPS on the bike and you can't read it without glasses, then you probably need bifocals.
A 'line bifocal' pair of glasses or sunglasses introduces a corrective segment at the bottom of each lens for your reading requirement. At Rapid Eyewear we set this dividing line 8mm from the bottom; this ensures you can look down through the segment for short vision, but enjoy perfect distance vision through the greater part of the lens when you're cycling or driving etc. If you require long-sighted correction only, we can add a reading segment at the bottom of the lens and leave the remainder effectively 'blank'.
How Strong Does a Prescription Need To Be Before I Bother With Correction?
There is no one-size-fits-all answer to this question, because it really depends on what you feel comfortable with when taking part in your chosen sport or leisure activity. Generally speaking, if your reading ('Add') requirement shown on your prescription is only +1.00 or less, you probably don't need glasses for close up viewing. At distance, the same applies, however if you have a CYL reading above approx. plus or minus 1.00 you have something called 'Astigmatism'; this means your cornea or lens isn't the perfectly curved shape we'd like it to be, which can cause slight blurring of your vision and also affects the ability of your eyes to resolve objects at distance into the correct shape. Whilst this may not be an issue when you're strolling along a beach, if you're trying to spot the bull an archery target some distance away it can be. For this reason it's worth considering corrective sunglasses for sports, even when you may not bother in your regular daily life.
If you are still unsure whether corrective sunglasses are right for you, or what type of correction you need, please take some advice from your optician.