Abstract
Purpose: :
To evaluate damage in normal and glaucomatous eyes, we measured the ganglion cell complex layer thickness of macular regions using spectral domain optical coherence tomography (SD-OCT).
Methods: :
RTVue-100(Optovue, Inc., Fremont, CA, USA) waswas used to map the macula over an area of 7-mm square. Macular OCT images were prepared for automatic segmentation using the GCC program. We measured the thickness of the macular ganglion cell complex layer (mGCCL) as a nerve fiber layer, ganglion cell layer with an inner plexiform layer, and that of the macular total retina (mTR) as the mGCCL with an outer retinal layer (mORL) (The mORL thickness was determined as the mTR thickness minus the mGCCL thickness). The results in G eyes were compared with those in N eyes. We also evaluated the co-efficiency of each thickness of the mGCCL, mORL and mTR and each mean deviation (MD) employing the Humphrey® Field Analyzer (HFA) using the SITA-standardTM program.
Results: :
The mGCCL was significantly thinner in G (78.90±14.88 µm) than the N (93.48±8.45 µm) eyes (p<0.001). Also the total retina was significantly thinner in G (250.54±22.38 µm) than in N (264.77±11.52 µm) eyes (p=0.002). However, the difference in mORL thickness between G (171.55 ±12.44 µm) and N (171.30±7.47 µm) was not significant (p=0.920). In G eyes the mGCCL showed more severe thinning (approximately 15%) than the mTR (approximately 5%). The co-efficiency of the mGCCL thickness and MD was significant (r=0.504, p<0.001), also, that of the mTR thickness and MD was significant (r=0.418, p<0.001). However, that of the mTR thickness and MD was non-significant (r=0.099, p=0.40) (MD of N : -0.18±0.56 dB, G : -12.30±9.54 dB).
Conclusions: :
Glaucoma leads to the thinning of the mGCCL and mTR. The MD (representing visual field loss), mGCCL and mTR thickness showed significant co-efficiency, but the mORL did not. Measurement of the mGCCL using RTVue-100 was suggested to facilitate effective glaucoma detection and evaluation.
Keywords: imaging/image analysis: clinical • nerve fiber layer • macula/fovea