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Ophthalmic instruments designed for assessing and/or training patients with eye fixation in points other than the central macula region of the retina (i.e., fovea), a condition known as eccentric fixation. The device measures the eyes\' perception of two conical, brushlike images with apexes touching (similar to a bow tie, known as Haidinger\'s brushes) when looking at a white surface through rotating polarized filters. Eccentric fixation assessment/training instruments may include speed control and reversal of rotation, and a light source that projects light dots to facilitate patient training. In patients with eccentric fixation the Haidinger\'s brushes are not centered on the central fixation dot, making possible the determination of the fixation point. These devices are used in patients with abnormal macular integrity and/or strabismus.
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