Abstract
Purpose: :
The fourier domain optical coherence tomograph (RTVue 100, Optovue Inc.) can measure the thickness of the ganglion cell complex (GCC) around the fovea. The GCC consists of the retinal nerve fiber layer, the ganglion cell layer, and the inner plexiform layer. The purpose of this study was to evaluate possible differences in GCC thickness among glaucoma patients, ocular hypertensives, and healthy subjects
Methods: :
Fifty-five eyes of 34 patients with primary open angle glaucoma (POAG), 19 eyes of 11 ocular hypertensive patients (OHT), and 20 eyes of 14 normal subjects were included. GCC was measured in all eyes. Early POAG was classified according to the enhanced visual field glaucoma staging system of Brusini. Ocular hypertension was defined as an intraocular pressure higher then 21 mmHg without visual field defects. Excluding parameters were advanced cataract, spherical and cylindrical refractive error higher than 5 diopters and 2 diopters, respectively, corrected visual acuity lower then 6/20, any previous ocular surgery or laser treatment and any retinal pathology. GCC results between groups were evaluated using Mann-Whitney-U-test.
Results: :
Glaucoma patients were significantly older (mean age 65.7 ± 5,7 years) compared to ocular hypertensives (mean age 59.6 ± 6.9 years) and normal patients (59.8 ± 7.1 years). The average of corneal thickness was 550.9 ± 33.6µm.Glaucoma patients had a mean GCC thickness of 84.0 ± 11.4 µm, 84.1 ± 10.9 µm in the superior hemisphere, and 84.0 ± 13.0 µm in the inferior hemisphere. OHT patients showed a mean GCC thickness of 95.4 ± 9.5 µm, 96.2 ± 9.7 µm in the superior hemisphere, and 94.6 ± 9.8 µm in the inferior hemisphere. Normal patients had a mean GCC thickness of 96.4 ± 5.1 µm, 95.0 ± 5.5 µm in the superior hemisphere, and 97.9 ± 5.4 µm in the inferior hemisphere. POAG patients had a statistically significant thinner GCC thickness compared to OHT and normal patients. There was no statistically significant difference in GCC thickness between OHT and normal subjects.
Conclusions: :
This is the first study evaluating the ganglion cell complex in different experimental groups using high resolution OCT. We found that glaucoma patients had significant thinner GCC thickness compared to the other groups. Further studies will show if the GCC has a diagnostic ability to detect early glaucoma.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical • retina: proximal (bipolar, amacrine, and ganglion cells)