Which deficits most directly compromise binocular fusion?

Which deficits most directly compromise binocular fusion?

• A. Saccade deficits only
• B. Pursuit deficits only
• C. Both saccade and pursuit deficits
• D. Neither

Answer: (C)

Binocular fusion relies on keeping the two eyes precisely aligned on the target across different kinds of eye movements. Saccades are the quick reallocations of gaze to a new target; if saccade control is impaired, the eyes may land misaligned, creating a brief disparity that fusion has to resolve. Pursuit moves the eyes smoothly to track a moving target; when pursuit is defective, the eyes can lag behind or overshoot, producing a time-varying disparity that makes maintaining single vision more difficult. Since both rapid reorientation and smooth tracking directly affect how the two eyes stay aligned on the target, deficits in either saccades or pursuit can directly compromise binocular fusion. Therefore, the best answer is that both types of deficits can disrupt fusion.

Binocular fusion relies on keeping the two eyes precisely aligned on the target across different kinds of eye movements. Saccades are the quick reallocations of gaze to a new target; if saccade control is impaired, the eyes may land misaligned, creating a brief disparity that fusion has to resolve. Pursuit moves the eyes smoothly to track a moving target; when pursuit is defective, the eyes can lag behind or overshoot, producing a time-varying disparity that makes maintaining single vision more difficult. Since both rapid reorientation and smooth tracking directly affect how the two eyes stay aligned on the target, deficits in either saccades or pursuit can directly compromise binocular fusion. Therefore, the best answer is that both types of deficits can disrupt fusion.