Final answer:
A normal healthy visual system corrects heterophoria through various mechanisms that maintain single and clear binocular vision, despite the slight misalignment of the eyes. This is an example of the adaptability and complexity of the brain's visual processing. Advanced processes like binocular depth cues and the visual cortex play critical roles in this automatic correction.
Step-by-step explanation:
In response to the question, a normal healthy visual system responds to heterophoria by using its complex mechanism to compensate for the slight misalignment of the eyes when they are not focusing on an object. The neural control of eye muscles ensures that any latent deviation in eye alignment does not affect binocular vision, maintaining a single, clear image. To explore the geometric optics of the eye, we consider that both eyes receive slightly different images due to their separate locations on the face. Our brains are able to integrate these images to perceive depth and a three-dimensional view of the world. This is achieved through various advanced processes such as crosstalk from one half of the brain to the other or the convergence and accommodation of the eyes that naturally occurs as part of normal binocular vision.
When a person has heterophoria, their eyes tend to drift out of alignment when not actively focusing or when covered, but the alignment returns with binocular vision. Binocular depth cues and the visual cortex play significant roles in this correction process. The visual cortex is adept at adjusting to changes and maintaining a coherent visual perception, as demonstrated in experiments where subjects adapt to an inverted visual field from prism glasses. The visual system's ability to compensate for heterophoria, like its adaption to other visual irregularities such as astigmatism, is a testament to the flexibility and complexity of the visual processing in the brain. Glasses with special lenses can be used to correct vision defects and aid the visual system in achieving clarity.