Diagnostic Accuracy of the Spectralis and Cirrus Reference Databases in Differentiating between Healthy and Early Glaucoma Eyes

Abstract

Purpose: To evaluate and compare the diagnostic accuracy of global and sector analyses for detection of early visual field (VF) damage using the retinal nerve fiber layer (RNFL) reference databases of the Spectralis (Heidelberg Engineering, Heidelberg, Germany) and Cirrus (Carl Zeiss Meditec, Dublin, CA) spectral-domain optical coherence tomography (SD OCT) devices.

Methods: Healthy subjects and glaucoma suspects from the Diagnostic Innovations in Glaucoma Study (DIGS) and African Descent and Glaucoma Evaluation Study (ADAGES) with at least 2 years of follow-up were included. Global and sectoral RNFL measures were classified as within normal limits, borderline (BL), and outside normal limits (ONL) on the basis of the device reference databases. The sensitivity of ONL classification was estimated in glaucoma suspect eyes that developed repeatable VF damage.

Results: A total of 353 glaucoma suspect eyes and 279 healthy eyes were included. A total of 34 (9.6%) of the glaucoma suspect eyes developed VF damage. In glaucoma suspect eyes, Spectralis and Cirrus ONL classification was present in 47 eyes (13.3%) and 24 eyes (6.8%), respectively. The sensitivity of the global RNFL ONL classification among eyes that developed VF damage was 23.5% for Cirrus and 32.4% for Spectralis. The specificity of within-normal-limits global classification in healthy eyes was 100% for Cirrus and 99.6% for Spectralis. There was moderate to substantial agreement between Cirrus and Spectralis classification as ONL.

Conclusions: The Spectralis and Cirrus reference databases have a high specificity for identifying healthy eyes and good agreement for detection of eyes with early glaucoma damage.

Figure 1

Case 1. Global RNFL Classification Disagreement between Cirrus (borderline) and Spectralis (outside normal limits) in Glaucoma Suspects Left: Cirrus scan showing global retinal nerve fiber layer classification as yellow, borderline (top right arrow), while most temporal clock hours are red, outside normal limits (left arrow). Right: Spectralis showing global retinal nerve fiber layer classification as red, outside normal limits (top arrow), while most temporal superior and temporal inferior sectors are red, outside normal limits (left arrow). Although global classification differs, both instruments identify temporal sectors (Spectralis) and clock hours (Cirrus) as outside normal limits.

Figure 2

Case 2. Global RNFL Classification Disagreement between Cirrus (outside normal limits) and Spectralis (borderline) in Glaucoma Suspects Left: Cirrus scan showing global retinal nerve fiber layer classification as red, outside normal limits (top right arrow), while most temporal clock hours are red, outside normal limits (left arrow). Right: Spectralis showing global retinal nerve fiber layer classification as yellow, borderline (top arrow), while most temporal superior and temporal inferior sectors are red, outside normal limits (left arrow). Although global classification differs, both instruments identify temporal sectors (Spectralis) and clock hours (Cirrus) as outside normal limits.