Topical Review: Methodological Variables in Clinical and Laboratory Measurements of Fixation Disparity.
Journal
Optometry and vision science : official publication of the American Academy of Optometry
ISSN: 1538-9235
Titre abrégé: Optom Vis Sci
Pays: United States
ID NLM: 8904931
Informations de publication
Date de publication:
01 08 2023
01 08 2023
Historique:
medline:
11
9
2023
pubmed:
12
7
2023
entrez:
12
7
2023
Statut:
ppublish
Résumé
Fixation disparity is a small vergence error that does not disrupt fusion. Fixation disparity measures correlate with binocular symptoms. This article covers methodological differences between clinical fixation disparity measurement devices, findings when objective and subjective fixation disparities are compared, and the potential impact of binocular capture on fixation disparity measurements. Fixation disparity is a small vergence error that occurs in nonstrabismic individuals and does not disrupt fusion. This article reviews clinical fixation disparity variables and their clinical diagnostic value. Clinical devices that are used to measure these variables are described, as are studies in which the output from these devices has been compared. Methodological differences between the devices such as the location of the fusional stimulus, the rate at which judgments of dichoptic alignment are made, and the strength of the accommodative stimulus are all considered. In addition, the article covers theories of the neural origins of fixation disparity and control system models incorporating fixation disparity. Studies in which objective fixation disparities (oculomotor portion of fixation disparity assessed with an eye tracker) and subjective fixation disparities (sensory portion of fixation disparity assessed psychophysically with dichoptic Nonius lines) have been compared are also examined, and consideration is given to why some investigators find differences in these measures, whereas other investigators do not. The conclusion thus far is that there are likely complex interactions between vergence adaptation, accommodation, and the location of the fusional stimulus that lead to differences in objective and subjective fixation disparity measures. Finally, capture of the visual direction of monocular stimuli by adjacent fusional stimuli and the implications for fixation disparity measures are considered.
Identifiants
pubmed: 37436811
doi: 10.1097/OPX.0000000000002041
pii: 00006324-990000000-00130
doi:
Types de publication
Review
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
572-594Informations de copyright
Copyright © 2023 American Academy of Optometry.
Déclaration de conflit d'intérêts
Conflict of Interest Disclosure: The author has no financial conflict of interest.
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