How to Increase Vision From 20/40 to 20/20 With Glasses

20/20 vision is not "perfect" vision, as it is sometimes mistakenly called, but is in fact a baseline figure for eye exams and vision acuity level that doctors often try to reach using corrective means like glasses and contacts. Your 20/40 vision can be brought to 20/20 vision using glasses. You will need the help of your optometrist (doctor of optometry, or OD) or ophthalmologist (a medical doctor, or MD, who specializes in the eye).

Instructions

• 1

  Understand vision acuity. Vision acuity is also sometimes called Snellen acuity, for the Snellen eye chart used in vision tests. A Snellen chart is a chart of black letters printed on a white background for a high level of contrast. The letters get smaller towards the bottom of the chart. Acuity is determined by how many feet away from the eye chart you can stand and still see the "20" line on the chart -- a pre-determined row of the chart. 20/20 vision means you can see that line from 20 feet away. 20/40 vision means that at 20 feet away from the chart, the last line you can read accurately is a line that a person with 20/20 vision would be able to see from 40 feet away.

• 2

  Obtain your eyeglass prescription. Your optometrist/ophthalmologist will determine the correct prescription for you. Prescriptions for glasses are measured in diopters. They start at plano (zero) and there are four quarters in a diopter. According to optometrist Wendy Strouse Watt, the usual prescription for 20/40 vision is -0.75. However, your doctor may consider other factors, such as variations in vision acuity in each eye and whether you are nearsighted or farsighted.

• 3

  Wear your glasses as directed by your doctor. Remember that your vision will only be corrected to 20/20 when you are wearing your glasses.