Retinal nerve fiber layer volume measurements in healthy subjects using spectral domain optical coherence tomography.

PURPOSE

To report retinal nerve fiber layer (RNFL) volume measurement using spectral domain optical coherence tomography (SD-OCT). We determined the characteristics and effecting factors of the RNFL volume in healthy eyes.

METHODS

Eighty-six eyes from 86 healthy volunteers were included. All participants underwent 3D-disc scanning using SD-OCT. We developed a computer program using Matlab software to extract RNFL thickness values from colored topographic RNFL thickness map. Total average, quadrant, and clock-hour RNFL volume were automatically calculated between 2.5 and 5 mm diameter circles using the length, width, and height of each pixel derived from the RNFL thickness map.

RESULTS

The mean total RNFL volume was 1.478±0.124 mm and RNFL volume profiles showed double-hump patterns. RNFL volumes of superior and inferior quadrants were significantly greater than those of temporal and nasal quadrants (all P<0.001). A strong correlation existed between RNFL volume and conventional circumpapillary RNFL thickness measured by built-in software (R=0.895 to 0.972). Image quality and age were associated with RNFL volume measurement.

CONCLUSIONS

RNFL volume measurement from RNFL thickness map analysis provides an alternative approach to characterizing and evaluating RNFL. RNFL volume measurement may be valuable for the objective and quantitative evaluation of 3-dimensional RFNL changes.