What is BVD?
What is Binocular Vision Dysfunction (BVD)?
Binocular vision dysfunction (BVD) is a visual condition where the line of sight from one eye tends to be slightly out of alignment with the line of sight from the other eye (usually vertical) and this puts a heavy strain on the eye muscles as they are constantly trying to correct the alignment to achieve single focus vision.
The cause can be secondary to normal facial asymmetry, acquired facial asymmetry from aging or head trauma from sports, or injury damaging the nerves to your eye muscles causing the imbalance.
This heavy strain on the eye muscles results in dizziness, headaches, disorientation, and reading difficulties. Some people suffer from only one symptom while others from multiple; which is why it can be so difficult to diagnose.
Symptoms of BVD
Those who suffer from Vertical Heterophoria or Superior Oblique Palsy tend to have a small amount of vertical eye misalignment, which the brain corrects by directing the eye muscles to properly reposition the eyes. However, using the eye muscles in this manner overworks them and they become strained and fatigued, causing the many symptoms of Vertical Heterophoria and Superior Oblique Palsy: