Abstract
Purpose: :
To compare the reproducibility between Stratus OCT and Cirrus HD-OCT in peripapillary retinal nerve fiber layer (RNFL) measurements in glaucomatous eyes
Methods: :
Twenty-two stable glaucoma patients of varying severity were included in the study. One eye of each patient was dilated and scanned 3 times during the initial session to determine the intravisit variability and 1 time on 4 subsequent sessions on different days within 2 months to determine the intervisit variability. The same Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) and Stratus OCT (Carl Zeiss Meditec, Dublin, CA) instruments were used in all testing sessions by the same operator. Fast RNFL imaging protocol of Stratus OCT was used to measure the peripapillary RNFL thickness. Optic Disc 200x200 scan protocol of Cirrus HD-OCT was used to measure the peripapillary RNFL thickness along a circle (r=1.73 mm) extracted automatically from a 6 mm x 6 mm cube centered over the optic nerve. Reported RNFL thickness values were: mean RNFL, four quadrant averages, and twelve clock-hour averages. Reproducibility was assessed with intrasession and intersession intraclass correlation coefficients (ICCs). An ICC >0.75 is considered excellent agreement. For both intra- and inter-session comparisons, McNemar’s test was used to determine if a preponderance of the 17 pairs of ICCs were greater for Cirrus HD-OCT versus Stratus OCT
Results: :
The ICCs for the Cirrus and Stratus RNFL measurements were similar. Cirrus HD-OCT showed greater ICCs in both intrasession [12 of the 17 (71%); p = 0.14] and intersession measurements [14 of 17 (82%) p = 0.013]. The ICCs of the nasal and temporal quadrants (as well as clock hours 3 and 9) were lower than those of other regions, more so with Cirrus HD-OCT than Stratus OCT
Conclusions: :
Both Stratus OCT and Cirrus HD-OCT have good and comparable reproducibility. Cirrus HD-OCT peripapillary RNFL thickness measurements were more reproducible in intersession comparisons than Stratus OCT. The improved Cirrus HD-OCT ICC, particularly superior and inferior RNFL quadrants may result in an improved accuracy in following glaucoma patients for progression
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer • imaging/image analysis: clinical