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Influence of convergence on vertical fusional vergence amplitude
Medical Research Foundation, India.
Medical Research Foundation, India.ORCID iD: 0000-0002-3745-0035
University of California, USA.
2005 (English)In: American Journal of Ophthalmology, ISSN 0002-9394, E-ISSN 1879-1891, Vol. 139, no 3 Suppl., p. S46-, article id EY313Article in journal, Meeting abstract (Refereed) Published
Abstract [en]

Purpose: Deficiency in vertical fusional vergence amplitude (VFVA) is known to cause asthenopia and oculomotor imbalances. The measurement of VFVA however is confounded by its increase with convergence (Hara et al., 1998). A quantitative relationship between the two vergences is thus necessary to predict the VFVA at a given convergence angle. Here, we sought to derive such a relationship by measuring the VFVA at a range of convergence angles. Methods: 30 subjects (17–21 yrs) wearing red-green goggles fused a pair of red-green concentric circles projected on a computer monitor at a distance of 50 cms in a dark room. The horizontal and vertical separation between the red-green circles determined the convergence and vertical vergence demand respectively. The VFVA was measured at 8 equally spaced convergence demands ranging from 0.58° to 11.13°. The convergence demands were either systematically increased or randomly varied across different sessions. in each session, the convergence demand was kept constant while the vertical vergence demand was varied in steps of 0.03°. The maximum vertical vergence demand that could be fused determined the VFVA. Results: The subjects’ data was divided into four groups based on the range of convergence demands that could be fused. in all the groups, the VFVA increased linearly with the systematic increase in convergence demand (mean regression equation: y 0.15x 0.49). Randomizing the convergence demands did not show any significant change in this relationship (y0.12x 0.80). Conclusion: The VFVA increases linearly in the range of convergence demands tested. The linear regression equation derived could be used in a clinical setup to predict the VFVA at a given convergence angle

Place, publisher, year, edition, pages
2005. Vol. 139, no 3 Suppl., p. S46-, article id EY313
National Category
Ophthalmology
Research subject
Natural Science, Optometry
Identifiers
URN: urn:nbn:se:lnu:diva-74516OAI: oai:DiVA.org:lnu-74516DiVA, id: diva2:1209920
Conference
2nd SERI-ARVO Meeting on Research in Vision and Ophthalmology. 16-20 February 2005, Singapore.
Available from: 2018-05-24 Created: 2018-05-24 Last updated: 2018-10-29Bibliographically approved

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https://www.ajo.com/article/S0002-9394(04)01617-4/pdf

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Baskaran, Karthikeyan

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CiteExportLink to record
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  • apa
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