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 compare d with confocal scanning laser ophthalmoscope (CSLO) measurements. METHODS. One randomly selected eye of 22 patients with idiopathic intracran ial hypertension (IIH) and a variable degree of optic disc swelling underwe nt five and three repeated measurements of disc height using high-resolutio n ultrasonography (Biovision unit; Quantel Medical, Clermont-Ferrand, Franc e) and CSLO (Heidelberg Retina Tomograph [HRT]; Heidelberg Engineering, Hei delberg, Germany), respectively. The same procedure was assessed in 14 subj ects with variable degrees of physiologic optic disc cupping. US and HRT me asurements from each group were individually compared with each other to es timate the accuracy of US readings in both disc conditions in comparison wi th HRT data. RESULTS. Ultrasonographic readings were positively correlated with HRT meas urements 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 0.2 4 +/- 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, respectivel y. CONCLUSIONS. The results indicate that US and CSLO readings are correlated in both disc swelling and cupping conditions, but to a different extent bec ause of a significant discrepancy in papilledema. US assessment can be cons idered highly reproducible. Combined US and HRT optic disc analysis may be recommended in papilledema evaluation as long as a better correlation can b e demonstrated in further studies.