fixation disparity
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Fixation disparity occurs when the visual axes of the eyes are not perfectly aligned on an object being fixated. It results in a small misalignment that falls within Panum's fusional area. Different types of fixation disparity include exo and eso disparities. Fixation disparity is a more useful measure of binocular vision status than phoria, as it can be measured under normal binocular viewing conditions, unlike phoria which requires dissociating the eyes. Fixation disparity curves provide information about the relationship between phoria and fixation disparity.
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Fixation disparity allows fixation without intersecting visual axes, noticeable within Panum’s area.
Introduces Panum’s area, an important concept in understanding binocular vision.
Describes EXO disparity (divergent) and ESO disparity (convergent), including vertical disparity.
Explores the connection between phoria and fixation disparity, indicating binocular system stress.
Discusses methods of demonstrating fixation disparity using binocular stimuli and fixation locks.
Presents fixation disparity curves, analyzing their significance and variations.
Discusses the prevalence of fixation disparity curves, clinical value, and measurement considerations in assessing binocular vision.
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fixation disparity
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- 2. Fixation Disparity Possibleto fixate an object without the visual axes intersecting If within Panum’s area a fixation disparity results
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- 5. Fixation Disparity EXOdisparity: axes slightly divergent ESO disparity: axes slightly convergent Vertical disparity also occurs
- 6. Phoria and FDRelationship between direction of phoria and direction of disparity Idea that presence of FD shows “stress” on binocular system
- 7. Phoria and FDPhoria: present when eyes are dissociated FD: present under binocular conditions FD: present under normal viewing conditions and may therefore provide a more useful measure of binocular status
- 8. FD Terminolgy Associatedphoria Uncompensated phoria
- 9. Demonstration of FDBinocular stimulus Monocular markers Central or peripheral fixation lock
- 10. Central or PeripheralFusion locks?
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- 17. Prevalence of FDCurves
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- 22. Summary A usefulclinical measure Measure at distance and near Do not use it as only measure of BV Part of overall BV assessment Only measure in BINOCULAR patients