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Online Eye Test for Reading Glasses
Healthy eyes require seeing your doctor in person at least every two years, but an online eye test for reading glasses can provide you with an early warning system for changes in your lenses. Questions you can expect on an online eye test. Most online eye tests begin with a few simple screening questions. You may be asked your age and gender, and then directed to a series of questions such as: These questions are designed to give indications of your need of corrective lenses for presbyopia and also to find indications of glaucoma, macular degeneration, and cataracts. Testing your eyes for presbyopia. Then a typical online test for your eyes will offer you 10 images requiring you to type the letter you see or identify part of a figure (usually which corner of a rectangle you see in a test box). The images used in the test are typically black and white, so that they work on all monitors. They are usually very small, but not so small that a single pixel would change your selection of an answer related to an image. The test may give you false indications of visual impairment, however, if it uses anti-aliased fonts (if it smoothes out the sharp edges of letters and figures with grey tones and half tones), if it is not programmed to compensate for variations in brightness and contrast, and if it was designed for 1064 x 768 screen resolution and you do not have this level of resolution on your computer. Testing your eyes for astigmatism. There are two common online tests for astigmatism. One requires you to look at a dot in the center of a grid, and to make your own assessment of whether you can see all the lines in the grid and whether some lines look wavy. Another requires you to look at the center of a group of concentric circles and make a judgment as to whether you can see all the circles. There are also online tests for color perception. If you cannot read the numbers in a field of red and green dots, you may be colorblind. What an online vision test can never tell you. No online eye test for reading glasses, unfortunately, can measure the pressure in your eye to determine if you have glaucoma, or check your retina for the early signs of diabetic retinopathy, or keep you from moving your head from side to side to see images on the screen if you have macular degeneration. No online eye test can give you a prescription for bifocals —but they may tell you generally what level of correction you need if you just need distance correction or near vision correction, that is, if you have uncomplicated myopia or presbyopia, but not if you need bifocals or correction for astigmatism. Use an online vision test for reading glasses as a first indicator that you need a different lens prescription. Then get the exact prescription from an optometrist or ophthalmologist, and buy eyeglasses online or from your dispensing optician. |