Ultrasonographic evaluation of optic disc swelling: comparison with CSLO in idiopathic intracranial hypertension.

PURPOSE To determine the accuracy and reproducibility of ultrasonographic (US) readings of optic disc elevations in patients with papilledema compared with confocal scanning laser ophthalmoscope (CSLO) measurements. METHODS One randomly selected eye of 22 patients with idiopathic intracranial hypertension (IIH) and a variable degree of optic disc swelling underwent five and three repeated measurements of disc height using high-resolution ultrasonography (Biovision unit; Quantel Medical, Clermont-Ferrand, France) and CSLO (Heidelberg Retina Tomograph [HRT]; Heidelberg Engineering, Heidelberg, Germany), respectively. The same procedure was assessed in 14 subjects with variable degrees of physiologic optic disc cupping. US and HRT measurements from each group were individually compared with each other to estimate the accuracy of US readings in both disc conditions in comparison with HRT data. RESULTS Ultrasonographic readings were positively correlated with HRT measurements in both swollen (r = 0.62, P: = 0.002) and excavated disc (r = 0.84, P: < 0.0002). The 95% limits of agreement between the instruments were 0.24 +/- 0.59 mm (mean +/- 2 SD) and 0. 05 +/- 0.3 mm for swelling and cupping measurements, respectively. The coefficient of variation was 7.63% and 1.8% for swelling and 7. 93% and 5.91% for cupping, with US and HRT, respectively. CONCLUSIONS The results indicate that US and CSLO readings are correlated i: both disc swelling and cupping conditions, but to a different extent because of a significant discrepancy in papilledema. US assessment can be considered highly reproducible. Combined US and HRT optic disc analysis may be recommended in papilledema evaluation as long as a better correlation can be demonstrated in further studies.