Fluorescein angiographic findings in optic discs with dysthyroid optic neuropathy

Abstract

The authors analyzed fluorescein angiographs (FAGs) of the optic discs and surrounding areas of 47 eyes from 33 cases of dysthyroid optic neuropathy (DON). The FAGs revealed a blurring of the disc or cup margin, dye leakage and vessel dilatation in cases with severe DON. In particular, changes in the upper and lower quadrants of the optic discs were observed even in the early stages of DON. While no arterial filling defects were detected, the authors frequently observed tortuosity or dilatation of the veins. Relative to the pre-treatment state, significant improvements of the blurring, dye leakage, vessel dilatation were observed in the post-treatment FAGs. The authors also found a significant reduction in arm to retina times (AkTs) following treatment. On the contrary, no significant changes were found in intra-retinal transit times (ITTs) between the pre- and post-treatment state in moderate to severe DON eyes. The preponderance of the evidence suggests that an impairment of venous return plays a major role in the pathogenesis of DON.

Key Words:

• dysthyroid optic neuropathy
• fluorescein angiography
• optic disc
• extraocular muscle
• pathogenesis
• venous return