Herman Snellen, a Dutch ophthalmologist, designed the first eye chart with which visual acuity could be measured. Referred to as the Snellen Chart, it was developed in 1862 and is still used today.
He set the baseline of measurement at twenty feet, the approximate distance at which light rays entering the eye are parallel and do not require our eyes to bend the rays to focus them upon the retina.
Snellen set the standard of 20/20 vision to represent “normal sight,” or what a person with normal vision could see at a distance of 20 feet. (Weber, Humphrey, and Silver 1997) We normally associate the term 20/20 with good vision; however, it does not, as some people think, mean perfect vision.
This means that a person with 20/40 vision must be 20 feet away to read what he or she should be able to read at 40 feet; a person with 20/85 vision must be 20 feet away to read what he or she should be able to read at 85 feet away, and so on.
This standard does not measure visual acuity at close distances. Similar charts were devised with smaller letters to read at a close range for the measurement of near vision.
If your vision is not 20/20, then you are not alone.
World wide, over 285 million people have visual impairments. Of that number over 39 million are blind. The other 246 million suffer some form of visual impairment from minor to severe.
According to the The Lighthouse National Survey on Vision Loss, “80% of global blindness is a result of five preventable or treatable conditions (cataract, refractive error, Trachoma, onchocerciasis and vitamin A deficiency).” They also say that, “The main causes of blindness are cataract (47.8%), glaucoma (12.3%) and age related macular degeneration (8.7%).”
The good news
There are steps that can be taken to prevent, delay, or halt the progress of the three major causes of blindness. Many of our previous posts have focused on the ways that you can prevent or halt the development of cataracts, glaucoma, and age-related macular degeneration. Look on the right under Topics and choose the one you want to read more about.
If you haven’t yet tried eye exercises to improve your nearsightedness, farsightedness, astigmatism and/or presbyopia (poor vision due to the aging process), now would be a good time to start. If you are unsure that the exercises would really help you, here are some free eye exercises that you can try at home.
The better news
Setting yourself a goal of reaching 20/20 vision is fine. However, keep in mind that any improvement is a step in the right direction. Allow time for the exercises and diet changes to work. While they have been proven to improve vision, this is not an overnight cure for all vision problems.
The best news of all
Changing your diet will not only help your eyes become more healthy, it will also help with your overall health as well.
You may be considering a change to an eye healthy diet which would include many fresh fruits and vegetables but you also get a healthier body as well. Two for the price of one is a pretty good deal!