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Actual visual acuity is measured by at what angular size you can see the smallest details at a distance and is called spatial resolving power. This must be measured for such purposes as determining the appropriate prescription that allows the best visual acuity so glasses or contacts can be gotten. The patient first notices many indications of eye diseases as visual disturbances so the doctor would look at the eye to determine if it is truly a vision problem or actually an underlying illness in the eye. In order to have great everyday performance and ability to see reading material clearly and with least amount of eyestrain, one must have good visual acuity. Many people must focus on fine details everyday, whether it is at work, home, or any other place. We rely on our eyes to pick up all the detail that is around us to give us the information we are looking for. Many of the daily tasks we take for granted are inspecting things for scratches, reading labels, gauges, and dials, and many more. We need good vision acuity to drive a vehicle and be able to know where we are going, read signs, and avoid hazards on the road. When the doctor hands you a prescription it reads as a fraction. The top number is the measured distance of 20 feet. The top number is the smallest detail you can focus on at the 20-foot distance. The higher the bottom number is the worse your visual acuity is and the closer you would have to stand to see what a 20/20 person could see at 20 feet. The smaller the bottom number is the better the vision, if the number is below 20 than you would have better than normal vision. So a person with 20/10 vision can see things at 20 feet that a normal person would have to be at 10 feet. Some of significant visual acuities are: 20/20 vision is considered normal vision 20/40 vision in at least one eye is the vision required to pass the driving test 20/200 vision or worse is the legal definition of blindness Vision tests are done on each eye separately to determine the acuity of each eye alone. Many people dont have the same acuity in both eyes. You will be sat in the chair and asked to put your chin on a rest with a machine that looks like extra large glasses. This machine will help determine what your visual acuity is by reading the letters on a chart on the wall in front of you. You must be able to read 50-75% of the first 6 lines of the chart to be considered 20/20 vision. The top letter is 20200 and id a person cannot read this with the best glasses they are considered legally blind. The second line on the chart is at 20/100 and the third line is 20/50. If you range in this area you would be considered disabled for occupations that require a lot of reading or numerical work. The forth line is 20/40 and is the line you need to be able to read to pass a drivers test in order to not be restricted on your license. The most commonly believed maximum acuity is at approximately 20/15. If you can read the bottom line of the chart well, you are probably guessing. Popping Peepers How your Contacts Can Accentuate your Eyes | ||
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