Purchase this article with an account.
K. Mah, M. Kwon, J. Byun, I. Jeon, J.-D. Kim; Prism Adaptation of Horizontal and Vertical Phoria by Prism induced Deviation. Invest. Ophthalmol. Vis. Sci. 2009;50(13):3824.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate the prism adaptation heterophorias and steroacuities were measured with introduction of horizontal or vertical prism during 30 minutes.
42 subjects (23 males, 19 females) aged 25.31±3.23 yrs who have normal binocular vision participated for this study. The amount of horizontal and vertical heterophoria response at distance(3m) and near(40cm) with binocular viewing were measured 6 times for 30 minutes after insertion 16Δ base-out, 8Δ base-in, 3Δbase-up and 3Δ base-down using Modified Thorington phoria test. After removal of the prism gradient AC/A ratio was immediately measured.
After insertion of 16Δ base-out, 8Δ base-in 3Δ base-up and 3Δ base-down prisms exodeviation, esodeviation, hyperdeviation and hypodeviation at distance and near were immediately induced respectively(p=0.00). The amount of induced deviation was 50% as much as amount of insertion prism and stereopsis was significantly decreased (p<0.02). At prism-induced deviation of base-down(p=0.04) and base-out(p=0.01), stereopsis were significantly recovered to the baseline throughout the time. The amount of deviation by prism was significantly related to stereopsis with exponential decay curve. Gradient AC/A ratio(3.21±2.19) after removal of base-out was significantly higher than baseline AC/A ratio(2.14±1.24)(p=0.01).
Prism-induced deviation and stereopsis in base-down and base-out were recovered to the baseline throughout the time. The prism induced deviation affects stereopsis.
This PDF is available to Subscribers Only