E Altpeter¹, S Trauzettel-Klosinski², M MacKeben3
¹University Eye Hospital, Dpt 1, Tuebingen, Germany; ²University Eye Hospital, Dpt 2, Tuebingen, Germany; 3Smith-Kettlewell Eye Research Institute, San Francisco, United States
Background: Patients with foveal vision loss due to maculopathy can use an intact retinal area adjacent to the central scotoma ('Preferred Retinal Locus', PRL). The reasons for the choice of a PRL location are still poorly understood. Topographic distribution of focal visual attention was measured to investigate a potential relationship between locations of higher attentional capabilities and a PRL location.
Method: Sustained attention was assessed in 23 patients with early stage of maculopathy and intact foveal fixation. 8 positions were tested (45° apart) at 8° eccentricity. During fixation of a central mark, a cue indicated the tested location (1sec). Sustained attention had to be shifted to this cued position. After a delay (2.5-4sec) the target (Snellen-E: 36-40arcmin, 60-190ms) appeared in the cued position while there were distractors in the other 7, followed by masks.
Results: We found an individual distribution of attention and 3 groups of attentional deficits: 1. upward, 2. downward, 3. upward and downward.
2 years later: 9 of the originally centrally fixating patients had developed eccentric viewing. In 8 of these 9 patients the PRL was located in an area of high attentional capabilities. If attentional performance in the lower visual field was good, the PRL was below the scotoma, if it was reduced, the PRL was right or left of the scotoma.
Conclusion: The choice of the PRL location after foveal vision loss is influenced by topographic features of sustained attention. This could have a practical consequence for the rehabilitation of these patients for choosing a favourable PRL for reading.
(supported by German Research Council (DFG Zr13/1 to STK))
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