Central retinal artery and vein collapse pressure in giant cell arteritis versus nonarteritic anterior ischaemic optic neuropathy.

Arteritic anterior ischaemic optic neuropathy and nonarteritic anterior ischaemic optic neuropathy are acute optic neuropathies, which have to be differentiated from each other. It was the purpose of this study to assess whether ophthalmodynamometry with an assessment of the collapse pressure of the central retinal artery (CRA) and vein (CRV) is helpful for that. Using a Goldmann contact lens-associated ophthalmodynamometer, the diastolic collapse pressure of the CRA and CRV were measured in six patients (eight eyes) with giant cell arteritis-induced anterior ischaemic optic neuropathy (GC-AION) and in 10 patients (12 eyes) with acute non-arteritic anterior ischaemic optic neuropathy (NAION). CRA collapse pressure was significantly (P=0.001; 95% confidence interval (CI): -68.7, -20.0) lower in the GC-AION group (52.7+/-24.6 arbitrary units) than in the NAION group (97.0+/-25.8 arbitrary units). CRV collapse pressure did not vary significantly (P=0.47). As measured by ophthalmodynamometry, CRA pressure is significantly lower in GC-AION than in NAION. CRV pressure does not vary markedly. These finding may be helpful for the clinical differentiation between GC-AION and NAION, and may give hints for the pathogenesis.