Diagnosis of Ocular Diseases Using Optical Coherence Tomography (OCT) at λ=840 nm
H. Ullah, M. Faran, Z. Batool, A. Nazir, G. Gilanie and N. Amin
Optical coherence tomography (OCT) is an imaging technique performed without any incision in the body and has a significant importance in biomedical diagnostics. OCT has been extensively used for early diagnose of ocular disease by obtaining two-dimensional (2-D) and three-dimensional (3-D) images. Using OCT with a superluminescent diode (SLD) laser with a wavelength, λ, of 840 nm we identified problems in the retina and optic nerve. OCT data set images were obtained from Sankara Nethralaya (SN) Eye Hospital, Chennai, India using a high-definition (HD)-OCT machine with a scan length of 2 mm and a raster scan protocol containing 512 × 1024 pixels for the identification of ocular diseases such as macular hole (MH), diabetic retinopathy (DR), age-related macular degeneration (AMD) and central serous retinopathy (CSR) for different patients of different ages. These images were processed using two different software packages: optical coherence tomography segmentation and evaluation (OCTSEG); and graphical interface for medical image analysis and simulation (GIMIAS) for further identification of fluid accumulation, vessel collapse, layer breakage and fluid drainage. OCTSEG was used to identify and separate different five layers. Each layer has been distinguished with colour. GIMIAS was used to colourize OCT images which can help us to observe and diagnose different problems in the layers. Each colourization has different benefit. Using this software, different area of a diseased eye can be easily detected. Finally, the comparison of three types of images made this diagnosis easier and clear.
Keywords: Superluminescent diode (SLD) laser, optical coherence tomography (OCT), retina, optic nerve, eye disease, optical coherence tomography segmentation and evaluation (OCTSEG), graphical interface for medical image analysis and simulation (GIMIAS)