Abstract
Purpose: :
To detect damage to specific macular areas in glaucomatous patients by optical coherence tomography (OCT)
Methods: :
11 eyes of 11 patients with perimetric glaucoma (PGEs), mean age 56±12 years, 7F and 4M, were studied. 11 eyes randomly selected in 11 healthy, age-matched, subjects were used as control eyes (CEs). All subjects had ametropia < 2D and underwent clinical examination including VA evaluation using ETDRS chart, slit-lamp biomicroscopy with +90 D lens and visual field testing. Macular morphology was studied with a high resolution spectral domain (SD) OCT Cirrus (Carl Zeiss Meditec, Inc., Dublin, CA) using Macular Cube 512x128 test; the Cirrus segmentation algorithm produced retinal thickness maps, which were averaged over 9 regions defined by a circular target centered at the fovea location. The 9 regions were: fovea (F); superior (sIM), inferior (iIM), temporal (tIM), nasal inner macula (nIM); and superior (sOM), inferior (iOM), temporal (tOM), nasal outer macula (nOM); total macular volume (tMV) was also calculated. Thickess measurements of homologous areas were compared to those of CEs. Data were analysed by one-way ANOVA. A level of p<0.05 was accepted as statistically significant.
Results: :
sIM, nIM, sOM, nOM, iOM and tMV were significantly thinner in PGEs than in the CEs (p=0.029, p=0.036, p=0.030, p=0.010, p=0.032, p=0.021, respectively). iIM and tIM reduction was not significant (p=0.058, p=0.053, respectively). F and tOM were unaffected (p=0.240, p=0.167, respectively).
Conclusions: :
Reported data show that, even if a diffuse macular thinning occurs in glaucomatous eyes, the main cellular loss is concentrated in specific areas of the retina: a selective damage occurs in papillo-macular region (nOM and nIM), where the density of ganglion cells is higher. An accurate imaging of specific macular structures is now possible with SD-OCT; as the damage in glaucomatous eyes involves since the beginning specific macular areas, we believe a careful study of these areas can be useful for an earlier diagnosis and to monitor the progression of the disease.
Keywords: macula/fovea • ganglion cells • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)