Abstract
Purpose:
The development of Optical Coherent Tomography (OCT) enables the thickness of the retinal nerve fiber layer (NFL), the ganglion cell layer and the inner plexiform layer (GCL+IPL) and the outer retinal layer (ORL) in the macular area to be evaluated separately. The purpose of this study was to determine the relationships among these three (NFL, GCL+IPL and ORL) OCT parameters in glaucoma patients.
Methods:
The parameters of the OCT were determined using the Topcon 3D OCT-2000 instrument. We compared the average thickness of the NFL, GCL+IPL and ORL in the macular area between subjects with glaucoma and normal controls. The relationships between the macular OCT parameters were determined using the regression analyses and the Akaike information criterion. The significance of the differences in the thicknesses of the OCT macular parameters of normal eyes and glaucomatous eyes was determined using t tests. A P value <0.05 was considered to be statistically significant.
Results:
Eighty-four glaucoma patients and 36 normal control subjects were studied. The NFL and GCL+IPL thicknesses in the normal group were significantly thicker than those in the glaucoma group (all P <0.0001). The outer retinal layer in glaucoma patients was thinner than that in normal subjects. However, the P values did not reach the level of significance (P=0.062). The relationships between the NFL of the macular area and the GCL+IPL were determined by third-order regression models. Changes in the average thickness of the NFL preceded changes in the average thickness of the GCL + IPL.
Conclusions:
Glaucoma mainly damages the inner-retinal layer in the macular area. There is a possibility that the loss of the outer retinal layer may be caused by glaucoma. Our results also suggest that the damage of the NFL preceded the damage of the GCL + IPL.
Keywords: 550 imaging/image analysis: clinical •
585 macula/fovea •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)