Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Purpose: The existence of asymmetries between the two eyes in the number and distribution of nerve fibers may possibly provide an early anatomic indication of glaucomatous disruption if a symmetrical pattern of nerve fibers is normally present. Normal subjects were tested to determine whether a high degree of correspondence of regional nerve fiber layer thickness exists between the fellow eyes. Methods: Nerve fiber layer thickness was inferred from retardation shift measured by a scanning laser polarimeter (Laser Diagnostic Technologies, Inc.) in 40 pairs of eyes from normal subjects. Total thickness and the pattern of nerve fiber thickness over 208 regions was compared between the paired eyes. Results: Inferred nerve fiber layer thickness in companion eyes was highly correlated (r=.90). Variation of the total nerve fiber thickness was much less between companion eyes than between eyes of different individuals. In terms of regional (i.e., local) interocular correspondence, the measurements in the inferior retina were observed to be highly similar in the two eyes, but a pronounced shift of the location of the superior peak (maximum thickness) in the left eye relative to the right was observed as well as differences between the two eyes in the thickness measurements at the nasal and temporal minima. Conclusion: Significant unexpected interocular asymmetries were detected in regions other than the inferior hemiretina. These interocular asymmetries may reflect previously unrecognized anatomic nerve fiber differences or systematic angular bias in the instrument for one eye relative to the other. In contrast to the regional measures, the measures of total thickness were very similar between the companion eyes suggesting that the assessment of interocular asymmetries of total thickness determined by polarimetry may offer potential for detecting glaucoma.

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Presentation Number SAfechtner0624
Keywords: polarimetry, nerve fiber layer, optic nerve, glaucoma