Fourier-domain optical coherence tomography and time-domain OCT have both showed that the retinal nerve fiber layer is significantly thinner in glaucomatous eyes.
The RTVue-100 is unique in its ability to measure the ganglion cell complex (GCC), compared with other FD-OCT instruments that are commercially available, and the GCC also was found to be significantly thinner in glaucomatous eyes, making the measurement potentially valuable for assessing patients with glaucoma, said Sunita Radhakrishnan, MD, at the annual meeting of the American Glaucoma Society.
Measuring the macular thickness for assessing glaucoma is not a new idea and has been done using TD-OCT, said Dr. Radhakrishnan, research director, Glaucoma Research and Education Group, San Francisco, and an associate at the Glaucoma Center of San Francisco.
Macular segmentation also has been performed with TD-OCT, but "compared [with] TD-OCT, FD-OCT permits more specific segmentation and is therefore potentially superior," according to Dr. Radhakrishnan and colleagues. In their retrospective study, they evaluated the correlation between the GCC and RNFL thicknesses in normal eyes, eyes with suspected glaucoma, and glaucomatous eyes by comparing the RNFL thickness measurement with TD-OCT and FD-OCT in the three groups of eyes.