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Should the Worth Dot test be used to diagnose monofixation syndrome?

1 May 2004


Traditionally, the standard Worth Dot flashlight has been used to evaluate sensory fusion. Clinicians have also used the Worth Dot test in a "walk-away' manner to measure the size of a suppression scotoma in patients with abnormal fusion. Because the size of the flashlight targets and the distance from the patient are known, the practitioner can calculate the estimated size of the suppression zone. The size and location of this scotoma has been used to diagnose monofixation syndrome. However, there have been no studies to show that this suppression does not occur in patients with normal sensory fusion. The primary purpose of this project was to establish normative data for the normal suppression responses on the walk-away Worth Dot procedure. Within our sample of observers with clinically normal binocular vision, we found that 66% reported transitory suppression at an approximate distance of 3.7 meters and 77% reported full suppression at an approximate distance of 4.5 meters as the Worth Dot test lantern was moved away. These results indicate that central suppression on the Worth Dot walk-away procedure is very common among normal observers. A secondary goal of this study was to determine whether the walk-away suppression distance is related to the response on the distance Worth Dot test. It was hypothesized that those subjects who showed a suppression response on the distance Worth Dot would also suppress at a closer distance on the walk-away. The difference for full suppression was striking: subjects who demonstrated suppression on the distance Worth Dot test gave a suppression response on the walk-away at 1.1 meters closer that those who did not suppress on the distance Worth Dot.


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