An objective method to define outlier optical coherence tomograms and repeatability of retinal nerve fibre layer measurements.

Purpose: To compare the variation in thickness and reflectivity of the retinal nerve fibre layer (RNFL), circumferentially and on repeated testing.

Methods: In 24 normal eyes and 38 eyes with different optic neuropathies or retinopathies, third-party optical coherence tomography (OCT) software defined the RNFL border based on the reflectivity pattern across the retina and also provided measurements of the mean reflectivity and total retinal thickness in addition to RNFL thickness. A new Gaussian filtering method was implemented so that the weight of the applied filter was varied for each of five individually repeated scans until an optimum weight filter was determined.