Comparison of Ultrahigh Resolution and Standard Optical Coherence Tomography for Imaging Retinal Pathologies

Abstract

Abstract: : Purpose: To compare the performance of ultrahigh resolution (UHR) optical coherence tomography (OCT) versus standard resolution OCT for imaging retinal pathologies. To identify retinal pathologies where UHR OCT yields information not available with standard resolution imaging. To apply UHR OCT results to improve the interpretation of standard resolution OCT images. Methods: An ultrahigh resolution UHR OCT system has been developed which enables imaging in the ophthalmic clinic using a high performance, low cost, compact femtosecond laser light source. UHR OCT achieves axial image resolutions of better than 3 µm. Comparative studies are performed using a standard resolution commercial OCT 3 instrument with a 10-15 µm axial resolution. UHR OCT and standard resolution imaging are performed in the same patients and results correlated with standard ophthalmoscopic examination including fundus photography, fluorescein angiography, and visual fields. Results: To date, more than 100 patients have been imaged. A cross section of retinal pathologies including various stage macular holes, macular edema, diabetic retinopathy, age-related macular degeneration, epiretinal membrane, central serous chorioretinopathy, and glaucoma has been surveyed. The improved axial resolution of the UHR OCT enables better visualization of intraretinal architectural morphology than standard resolution OCT. Imaging retinal pathologies provides an approach for conclusively interpreting the intraretinal features seen in UHR OCT. UHR OCT is especially powerful for visualizing retinal pathologies affecting specific intraretinal layers such as the ganglion cell layer, the photoreceptors, and the nerve fiber layer. At the same time, UHR OCT provides a baseline for interpreting features seen with standard resolution OCT. Conclusions: UHR OCT enables significantly better visualization of changes in intraretinal morphology associated with many retinal diseases. These studies identify situations where improved visualization can provide important diagnostic information. At the same time, comparative studies of UHR and standard resolution OCT provide a baseline for better interpretation of features visualized with standard resolution OCT.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, S • imaging/image analysis: clinical • retina