Abstract
Abstract: :
Purpose: To present and test a new interpretation concept, the Nerve fiber layer Symmetry Test (NST), for computerised evaluation of retinal nerve fiber layer thickness (RNFLT) as measured by optical coherence tomography (OCT) in glaucoma. Methods: In a pilot study, 32 healthy and 40 age–matched glaucomatous eyes were included and examined by OCT, computerised perimetry, RNFL/disc photography, tonometry, and a basic eye examination. The NST concept includes consideration of the degree of symmetry of the peripapillary RNFLT around the horizontal meridian. Results: The observed NST sensitivity and specificity were high; 38/40 eyes (95%) and 32/32 eyes (100%), respectively. After correction of the OCT RNFLT measurement for the influence of variability in image signal/quality the NST sensitivity and specificity were 40/40 eyes (100%) and 31/32 eyes (97%), respectively. Whether RNFLT measurements were not or were corrected for variability in image signal, NST sensitivity was higher compared to the single most sensitive traditional OCT RNFLT parameter (the peripapillary inferior quadrant and the full circle means, respectively), but the difference was not statistical significant in this small sample. Conclusions: NST showed high specificities and sensitivities for detection of RNFLT attenuation indicating early to severe glaucoma. Although promising, the NST needs to be validated in larger study samples and in patients with various stages of glaucomatous damage.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer