Correlation of Optical Coherence Tomography Nerve Fiber Thickness Measurements with Visual Field Abnormalities in Glaucomatous Eyes

Abstract

Abstract: : Purpose:To correlate the severity and location of peripapillary RNFL measurements performed by Optical Coherence Tomography (STRATUS OCT) with the severity and location of visual fields defects in glaucomatous eyes. Methods:65 eyes of 65 glaucoma patients underwent STRATUS OCT testing using 3.4mm fast scans around the optic nerve head and Humphrey 24–2 visual field tests within 6 months of each other. OCT images were analyzed and coded as normal, 5%, and 1% using the normative database, which compares RNFL thickness with age–matched controls. The data were divided into superior, temporal, inferior and nasal quadrants about the ONH. Garway–Heath’s 6 ONH sectors and their corresponding 6 visual field areas were grouped into 4 similar quadrants and 4 corresponding mirror image areas of the VF, respectively. The percentage of abnormal visual field test points in each area was compared with the age–corrected abnormality score of the RNFL thickness in the matching ONH location. Correlations were assessed with Spearman’s ranked correlation coefficient. Results:Of the 65 glaucoma patients (69.6 yrs ± 15.0 yrs), 43(66%) were female and 22(34%) male. The average RNFL thickness correlated well with visual field severity scores, mean deviation, and pattern standard deviation. There was excellent correlation between the location and severity of RNFL thinning in the superior and inferior quadrants. Correlation was fair in the temporal quadrant and poor in the nasal quadrant. Conclusions:The degree of abnormality in average RNFL thickness correlates well with visual field severity score, MD and PSD, suggesting a strong relationship between RNFL thinning and visual field loss in glaucomatous eyes. The degree of RNFL thinning, especially in the inferior and superior portions of the ONH, correlates well with visual field defects in corresponding areas of the VF. Results with Correlation Coefficients and Significance Values 

Keywords: visual fields • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer