[Echographic differential diagnosis of optic nerve widening].

INTRODUCTION

Standardized echography is a well-established examination technique in ophthalmology. Among other things one of the more important uses is the evaluation of the optic nerve and its abnormalities. One aspect is the use of the stretch-test (originally called the "30 degrees-test") for the differential diagnosis of optic nerve widening. Such widening can be caused by solid thickening of the optic nerve and/or its sheaths or by solid infiltration of the subarachnoidal space. More frequent is a widening of the optic nerve as a consequence of sheath distension by increased subarachnoidal fluid.

PATIENTS AND

METHODS

We present various cases of widened optic nerve patterns and explain the technique and diagnostic value of standardized echography, especially of the stretch-test.

RESULTS

In widened optic nerve patterns due to fluid around the optic nerve parenchyma, a decreased optic nerve thickness will be found when performing the stretch-test (positive test result), whereas in solid lesions of the optic nerve no change of optic nerve thickness will be seen (negative test result).

CONCLUSION

The stretch-test provides a reliable tool for the differential diagnosis of widened optic nerves.