Is Single Measurement Enough to Get a Reliable Result with Optical Coherence Tomography?

Abstract

Pur po se: To evaluate the repeatability and reliability of retinal nerve fiber layer (RNFL) thickness measurements using optical coherence tomography (OCT). Ma te ri al and Met hod: Two hundred sixty-six eyes of 135 subjects (glaucoma, glaucoma suspects and healthy) were included in this study. Three sequential inferior, superior, nasal and temporal RNFL thickness measurements were performed using Spectral OCT [Opko/OTI, Inc., Miami, FL] by one operator at one session without pupillary dilatation. The differences between these three measurements of each quadrant in each eye were compared in microns and percentages. Repeated measures analysis of variance was performed for statistical analysis. Reliability is measured by intraclass correlation coefficient (ICC) for each quadrant. Re sults: ICCs of all quadrants ranged between 0.77 and 0.92, with the measurements of nasal quadrant being the least reproducible and the inferior being the most reproducible of all quadrants. RNFL measurement errors over 20% were seen in 9.63% of nasal quadrant, 5.3% of temporal quadrant, 0.6% of superior quadrant and only 0.3% of inferior quadrant measurements. Dis cus si on: In order to get more repeatable and reliable results with OCT, sequential measurements more than one should be considered. We believe that special attention is required in the analysis of data of nasal and temporal quadrants. (Turk J Ophthalmol 2012; 42: 11-5)

Keywords

• Glaucoma
• optical coherence tomography
• reliability
• repeatability
• retinal nerve fiber layer