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Lisa Asper, Kathleen Watt, Alice Chan, Angie Tang, Pauline Kang; Dissociation before accommodative function tests does not appear to impact results. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2963.
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© ARVO (1962-2015); The Authors (2016-present)
To determine the effect of testing order, ie associated or dissociated binocular function tests first, on the results of subsequent binocular function tests. The hypothesis is that the results of associated tests will be affected by previous dissociation during binocular function tests.
Twenty-eight young adults (19.1±1.0 years; 17 F, 11 M) without strabismus, amblyopia or current vision training were recruited and randomised into two groups. One group (n=14) was assigned to have associated followed by dissociated binocular function tests while the other group (n=14) was assigned to undergo the opposite testing order. Following a minimum 1 day break, the same tests were repeated but order of testing was swapped for both groups. Categorised as associated tests were horizontal fixation disparity (Saladin near point card), stereopsis (Randot test), accommodative accuracy (Binocular Fused Cross-Cyl test) and negative/positive relative accommodation (NRA/PRA). Categorised as dissociated tests were horizontal near phoria (Howell card and Modified Thorington), monocular amplitude of accommodation (push in and out tests) and monocular accommodative facility (MAF) with ±2.00D flippers.
There was no effect of order of testing on fixation disparity, stereopsis, binocular accommodative accuracy, near phoria, monocular amplitude of accommodation or MAF measures (all p>0.05). However, when dissociated tests were conducted first, PRA was significantly reduced by +1.00±1.32 D (t=3.733; p=0.003).
Overall there does not seem to be a significant impact of order of testing. However, PRA was affected by prior dissociation in young adults. These results need to be verified in children and individuals with binocular vision anomalies and include other measures of fusional vergence.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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