To identify the risk factors associated with false negative findings of optical coherence tomography (Stratus OCT) in patients with photographic localized retinal nerve fiber layer (RNFL) defects.

Twenty-four patients with preperimetric glaucoma and 173 patients with perimetric glaucoma, all with localized RNFL defects were included in the present study. The patients were divided into 2 groups according to the presence or absence of detection of photographic defects by OCT. Gender, age, refractive error, diabetes, hypertension, central corneal thickness, type of glaucoma, mean deviation, pattern standard deviation, average RNFL thickness, disc area, and photographic RNFL defect related variables (location, number, and angular width) were compared between the 2 groups. Each variable was initially evaluated by univariate analysis and significant variables ( p < 0.1) were included in the logistic regression analysis.

Photographic RNFL defects were not detected by OCT in 51 (25.9%) of the 197 eyes. The angular locations and widths of RNFL defects by OCT were significantly correlated with those of RNFL defects by red-free RNFL photographs (Pearson correlation coefficient R = 0.98 and 0.64, respectively). Logistic regression analysis revealed the risk factors for false negative findings of OCT included average RNFL thickness (odds ratio = 1.106, 95% confidence interval [CI] = 1.057-1.156, p < 0.001) and angular width of defect (odds ratio = 0.929, 95% CI = 0.884-0.977, p = 0.004).

This present study suggests that false negative findings of OCT in patients with photographic localized RNFL defects were associated with thicker RNFL thickness and smaller angular width of RNFL defect.