Rates of Abnormal Retinal Nerve Fiber Layer and Ganglion Cell Layer OCT Scans in Healthy Myopic Eyes: Cirrus Versus RTVue

BACKGROUND AND OBJECTIVE: To compare rates of abnormal peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell layer scans acquired with Cirrus HD-OCT (Carl Zeiss Meditec, Inc., Dublin, CA) and RTVue-100 (Optovue Inc., Fremont, CA) in healthy myopic eyes. PATIENTS AND METHODS: Forty-one non-glaucomatous myopic eyes (41 individuals) were scanned with Cirrus to measure RNFL and ganglion cell-inner plexiform layer (GCIPL) and with RTVue to measure peripapillary RNFL and ganglion cell complex (GCC) thicknesses. Rates of abnormal scans were calculated and compared between devices. Inter-device agreement in falsely classifying scans as abnormal was also assessed. RESULTS: The rate of abnormal average and four-quadrant RNFL was 4.8% to 7.3% on Cirrus and 2.4% to 9.7% on RTVue (P > .05). The overall rate of abnormal scans was 19.2% on Cirrus and 29.3% on RTVue (P = .3). Rates of abnormal Cirrus average and segmental GCIPL (12.2% to 17%) were similar to those of RTVue average and segmental GCC (9.7% to 14.6%) (P > .05). The overall rate of abnormal GCIPL (36.6%) was higher than that of GCC (14.6%) (P = .023). The inter-device agreement was poor for average RNFL (κ = -0.09), very good for average ganglion cell (κ = 0.81), and fair for overall RNFL (κ = 0.35) and overall ganglion cell (κ = 0.34). CONCLUSION: The high rates of abnormal RNFL and ganglion cell layer scans on both devices call for caution, particularly when attempting to diagnose glaucoma in myopic eyes using these devices. The RNFL and ganglion cell layer analyses may not be interchangeable on either of these devices. These two devices are not interchangeable for classifying healthy myopic eyes based on RNFL or ganglion cell layer analysis.