Abstract
Purpose: :
Paracentral visual field defects are the prime cause for decreased quality of vision in glaucoma patients. This study aimed to determine whether the roximity of abnormal macular thinning to the central fovea correlated with the aracentral visual field defects in eyes with early glaucoma.
Methods: :
Twenty-seven eyes of 23 patients with open-angle glaucoma were enrolled from January 2010 to October 2011. Patients with a spherical equivalent (SE) of <-6 diopters and mean deviation (MD) of <-6 dB were excluded. The mean age was 55.4 years, mean SE was -3.0 diopters, and mean MD was -2.7 dB. Thickness of the nerve fiber layer (NFL), ganglion cell layer + inner plexus layer (GCL+), and ganglion cell complex (GCC = NFL + GCL+) in the macula were measured using spectral-domain optical coherence tomography (3D OCT-2000, Topcon, Japan), and the areas with thickness outside the lower 99 percentile confidence intervals of the intrinsic normative database were defined as areas of abnormal thinning. The minimal distance between the central fovea and the areas for abnormal thinning was measured at every 1 degree. The distance was averaged every 30 degrees to obtain 12 sectorial average distances. A minimal distance among the 12 sectorial distances was defined as the proximal distance between the central fovea and the diminished macular structures, such as the NFL, GCL+, and GCC. The number of the <1% visual field defect points within 5 degrees (termed "paracentral defect") in the pattern deviation map of the Humphrey 24-2 SITA standard program was counted in each eye.
Results: :
There were no paracentral defects in 11 eyes (group1), 1 paracentral defect in 12 eyes (group2), and 2 paracentral defects in 4 eyes (group3). The proximal distance was 1.41 mm, 0.91 mm, and 0.53 mm for the NFL thinning area; 1.66 mm, 0.82 mm, and 0.39 mm for the GCL+ thinning area; and 1.65 mm, 0.84 mm, and 0.41 mm in the GCC thinning area for group1, group2, and group3, respectively. The proximal distance was significantly different among the 3 groups in all the 3 layers (P < 0.01, one-way ANOVA). The number of defects and the proximal distance were negatively correlated (NFL, rs = 0.64, P < 0.001; GCL+, rs = 0.56, P < 0.01; GCC, rs = 0.57, P < 0.01, Spearman's rank correlation coefficient).
Conclusions: :
The shorter distance from the central fovea to the area of abnormal macular thinning may be associated with greater paracentral defects.
Keywords: imaging/image analysis: clinical