Techlicious just interviewed Dr. Dominick Maino, an eye expert who we actually turned to about a year ago when Samsung issued its 3DTV warning. Well, Dr. Maino is back at it again, only this time he’s got some advice on how you can test your 3D vision at home.
It’s called the Brock String test and all you need is, yes, a string to determine whether you may have vision problems that are interfering with your ability to see 3D. First, find a string the length of your arm and tie a knot in the middle of it. Then tie two more knots approximately four inches from each of the string’s ends.
Hold one end of the string to your nose so that the closest knot to your face is about two inches away. Have another person hold the other end of the string. The string should be held taut, but should point down slightly. As your vision jumps from knot to knot you should see the string double, forming an “X” shape. This “X” should cross at the knot you are looking at.
For example, if you’re looking at the middle knot, the “X” will look perfect. If you’re looking at the knot farthest from you, then the lower half of the “X” will be significantly wider than the upper half. If you’re looking at the knot closest to you, then the top half of the “X” will be significantly wider than the bottom half.
If your “X” appears to cross in front of or behind the knot you’re looking at, you may have a binocular vision problem. This can cause problems when trying to view 3D images. You may experience dizziness, nausea or headaches, or you may not see the 3D image at all.
Dr. Maino notes that glasses or vision therapy may help a binocular vision problem, which is said to affect about 16 percent of the population. While this isn’t a fool-proof test or a way to self-diagnose an eye condition, it can provide you with a gauge for whether or not you’ll have problems with 3D viewing.
Despite all the great, new 3D gadgets out there, if you have problems seeing 3D or experience any unfavorable symptoms you should discontinue your 3D use and check with your doctor.