I’ve already talked multiple times about how vision issues can lead to bad experience when viewing stereoscopic 3D content, but still a lot of people believe that their vision is good enough and it is certainly not causing them any problems, and instead the stereo 3D content is bad or the technology is not good enough. And while the case may be that you are watching some bad quality 2D to 3D conversion, or using bad quality S3D viewing technology, even the viewing conditions may not be good enough and so on resulting in a bad experience, you could also have some issues with your vision as well. Have in mind that having trouble when watching stereo 3D content can be a hint that you need to go to a specialist to examine your eyes as you might just need to get a glasses (or new ones if you are already wearing prescription glasses), but sometimes there could be a more serious issue that needs extra attention. Having a normal vision (normal visual acuity), often referred to as 20/20 vision or 6/6 vision is good sign that your eyes are Ok and if you are experiencing trouble when watching stereoscopic 3D content, then the issue might be in something else. You need to be sure that the problem is not within your eyes as good eye health and proper vision is important in our everyday life and not only for watching stereo 3D content. Having vision problems such as nearsightedness (myopia), farsightedness (hyperopia), astigmatism or presbyopia can also cause issues with having good experience when watching stereoscopic 3D content, so if you suffer from any of those you will need to wear the proper prescription glasses or lenses in order to correct them and have normal vision restored.
How do you know if you need to go see a specialist and have your eyes examined? I’ve already mentioned that having trouble when watching stereoscopic 3D content such as experiencing headache, dizziness, disorientation or nausea while watching or after watching something in stereo 3D is a good sign that you might need to go see a specialist. But you can use another simple test that can help you give you an idea on what is your vision acuity at home and see if you need to go to a specialist and have your vision examined. All you need is a printer and a friend to help you take a test of your vision by using a version of the popular Snellen eye chart, variation of which is often used by eye care professionals to check patient’s vision. You need to download and print the eye chart from the link below (A4 size version and Letter version available), make sure you use the actual size when printing and don’t resize to fit. Then hang it on a wall in a well lit room (including the chart) with a friend staying next to the chart to help you take the test, measure 10 feet (or 3 meters) from the chart and stand there. Normally the distance is 20 feet or 6 meters with larger chart, but since you may have trouble finding the needed space the charts have been resized for taking the test at half that distance. To take the test you need to first cover one of your eyes with the palm of your hand and try to read aloud all the letters you see line by line the best you can, and the person helping you checks if you have read them correctly marking where and how many mistakes you make (if you make any). Then you change the eyes and repeat the procedure again with the person helping you noting where you make mistakes, if you make any, so that you can compare the results from both eyes as they may have different level of vision acuity.
And now comes the time to check the results. If you are able to read without making any mistakes all of the letters top to the bottom of the chart with both eyes, this means that you have what is considered to be normal vision (maybe even better than that), so you have no reason to worry. If you are having trouble reading without a mistake not only the bottom line, but the 2-3 of the ones above it, then you probably have a near-normal vision which normally should not cause you problems, but it is still a good to check your eyes. The suggestion to go see a specialist is even more important if you have a difference of two or three lines from the chart that you have no trouble reading with one of your eyes and the other. If you are having trouble properly reading even higher lines in the chart or the difference between what you can read with your left eye is even bigger than with your right eye you must go and see a specialist to have your vision examined. If you are already wearing contact lenses or prescription glasses you might want to do the test with and without wearing them to see what will be the results. This way the test may also give you an idea if you need to increase or decrease the diopter you currently have in case your vision has improved or became worse than the last time you’ve had it examined.
Have in mind that this simple way to check your vision is just to give you a basic idea on how good it is and is intended more to give you a hint if you need to go and see a specialist and have your eyes examined. It is not intended to replace a proper eye examination by a specialist, it might just point out the need for doing such an exam! Have in mind that the above test is not intended to directly check for potential problems of your stereoscopic vision, it is for checking the vision acuity. I do hope that you find this useful…