Effects of earth-fixed vs head-fixed targets on static ocular counterroll.
| Autor: | Chandrakumar M; Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada., Hirji Z, Goltz HC, Mirabella G, Blakeman AW, Colpa L, Wong AM |
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| Jazyk: | angličtina |
| Zdroj: | Archives of ophthalmology (Chicago, Ill. : 1960) [Arch Ophthalmol] 2010 Apr; Vol. 128 (4), pp. 413-7. |
| DOI: | 10.1001/archophthalmol.2010.14 |
| Abstrakt: | Objective: To investigate whether static ocular counterroll (OCR) gain is reduced during viewing of an earth-fixed vs a head-fixed target. Methods: Twelve healthy individuals were recruited. The target consisted of a red fixation cross against a grid pattern at a viewing distance of 33 cm. The target was mounted on a wall (earth fixed) or was coupled to the head (head fixed). Changes in mean torsional eye position were plotted as a function of head position steps (0 degrees +/- 25 degrees in 5 degrees steps), and sigmoidal fits were performed. Mean static OCR gain was calculated by taking the derivative of the fitted functions. Results: Mean static OCR gain was 40% lower with a head-fixed target (-0.084) than with an earth-fixed target (-0.141) (P < .001). Conclusion: The reduction in static OCR gain during viewing of a head-fixed target indicates that static OCR is partially negated when a target moves with the head. |
| Databáze: | MEDLINE |
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