Título

OPTIC DISC RIM AND RETINAL NERVE FIBER LAYER RELATIONSHIP IN EYES WITH DISCREPANT CLINICAL AND AUTOMATED OCT DELIMITATION

Objetivo

Bruch's membrane opening (BMO) demarcation of the Optic Nerve head (ONH) determined by the spectral-domain Optical Coherence Tomography (sdOCT) may not be coincident with clinical delimitation of the ONH boundaries. This study compared the relationship of Minimum Rim Width (MRW) and circumpapillary Retinal Nerve Fiber Layer (cpRNFL) thicknesses between OCT scans taken automated (using BMO) versus edited by a glaucoma specialist.

Método

Thirty-two healthy eyes underwent sdOCT examination (Spectralis, Heidelberg Engineering, Germany). The 360-degrees 48 pairs of sdOCT scans measures (MRW minus 3.5 mm cpRNFL thickenesses) from eyes with coincident BMO and clinical ONH boundaries' demarcation were used to construct a pattern polar curve (figure 1). Similar polar curves were constructed from 26 eyes of healthy patients without the coincident boundaries (automated). Then, BMO demarcations were artificially edited by a glaucoma specialist (clinical), moving BMO positions to those considered as the ONH boundaries in the en face OCT image. Non-parametric tests were used to compare the automated and the clinical polar curves using the pattern polar curve as reference.

Resultado

The vertical positions of the ONH showed the higher values of discrepant proportions of MRW-cpRNFL compared to the pattern polar curve. Mean discrepant proportions of the cilinical delimitation of the ONH was 35% lower than the automated one (median±standard error: 17.0±1.7 versus 23.0±1.8 um respectively; p=0.006).

Conclusão

Based on the results, the positioning of BMO demarcation to the clinical ONH boundaries in eyes with non-coincident delimitation showed better proportion of MRW-cpRNFL thicknesses. Further studies involving glaucoma patients may confirm the advantages of editing the BMO demarcation if it is not coincident with the clinical delimitation of ONH.