Rune L Brautaset1, Adrian J M Jennings. 1. Binocular Research Lab, Unit of Optometry, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden. rlb@ste.ki.se
Abstract
PURPOSE: To evaluate the effect of orthoptic treatment on the AC/A (A, accommodation; C, convergence) and CA/C ratios in subjects with convergence insufficiency (CI). METHODS: The change in AC/A and CA/C ratios after a 12-week period of home-based orthoptic treatment was examined in 10 subjects (mean age, 25.4+/-4.1 years [SD]). Both the AC/A and CA/C ratios were measured by using gradient response methods. For the AC/A ratio, the gradient phoria method was used, and for the CA/C ratio the prism-induced change in accommodation was measured with a refractometer. RESULTS: No change in the AC/A and CA/C ratios (P>0.05) were found after orthoptic treatment. However, improvements were found (P<0.05) in the fast and slow vergence mechanisms. CONCLUSIONS: Despite improvements in the fast and slow vergence mechanisms no change was found in the AC/A and CA/C ratios after orthoptic treatment in CI subjects. This finding is unexpected in light of the present understanding of CI, and an alternative theory is proposed.
PURPOSE: To evaluate the effect of orthoptic treatment on the AC/A (A, accommodation; C, convergence) and CA/C ratios in subjects with convergence insufficiency (CI). METHODS: The change in AC/A and CA/C ratios after a 12-week period of home-based orthoptic treatment was examined in 10 subjects (mean age, 25.4+/-4.1 years [SD]). Both the AC/A and CA/C ratios were measured by using gradient response methods. For the AC/A ratio, the gradient phoria method was used, and for the CA/C ratio the prism-induced change in accommodation was measured with a refractometer. RESULTS: No change in the AC/A and CA/C ratios (P>0.05) were found after orthoptic treatment. However, improvements were found (P<0.05) in the fast and slow vergence mechanisms. CONCLUSIONS: Despite improvements in the fast and slow vergence mechanisms no change was found in the AC/A and CA/C ratios after orthoptic treatment in CI subjects. This finding is unexpected in light of the present understanding of CI, and an alternative theory is proposed.
Authors: Tara L Alvarez; Vincent R Vicci; Yelda Alkan; Eun H Kim; Suril Gohel; Anna M Barrett; Nancy Chiaravalloti; Bharat B Biswal Journal: Optom Vis Sci Date: 2010-12 Impact factor: 1.973
Authors: Tara L Alvarez; Eun H Kim; Vincent R Vicci; Sunil K Dhar; Bharat B Biswal; A M Barrett Journal: Optom Vis Sci Date: 2012-12 Impact factor: 1.973