Heterophoria is the term used to describe a condition where the eyes have a tendency to misalign when they are not actively being used for focusing, such as when one eye is covered. In everyday use, the eyes remain aligned, often referred to as a "latent squint."
In more detail:
- The Tendency: Heterophoria represents a latent misalignment. This means the misalignment is present when the visual system isn't actively correcting for it.
- Compensation: When both eyes are open and working together (binocular vision), the brain exerts extra effort to keep the eyes aligned, preventing double vision and maintaining single, clear vision.
- Latent Squint: The term "latent squint" accurately describes this condition because the misalignment is hidden (latent) under normal viewing conditions.
- Difference from Strabismus (Tropia): Unlike strabismus (also known as tropia or manifest squint), where the misalignment is constant and noticeable, heterophoria is only apparent when the binocular vision is disrupted.
Heterophoria can sometimes cause symptoms like eye strain, headaches, blurred vision, or difficulty with reading, especially after prolonged visual tasks. These symptoms arise from the extra effort the eye muscles expend to maintain proper alignment. Treatment options range from vision therapy exercises to special eyeglasses that can help reduce the strain.
