Anterior Segment OCTA of Melanocytic Lesions of the Conjunctiva and Iris

The retinal vasculature is involved in many ocular diseases that cause visual loss. Although fluorescein angiography is the criterion standard for evaluating the retina vasculature, it has risks of adverse effects and known defects in imaging all the layers of the retinal vasculature. Optical coherence tomography (OCT) angiography can image vessels based on flow characteristics and may provide improved information.

Optical coherence tomography (OCT) provides non-contact, rapid in vivo imaging of ocular structures, and has become a key part of evaluating the anterior segment of the eye. Over the years, improvements to technology have increased the speed of capture and resolution of images, leading to the increasing impact of anterior segment OCT imaging on clinical practice. In this review, we summarize the historical development of anterior segment OCT, and provide an update on the research and clinical applications of imaging the ocular surface, cornea, anterior chamber structures, aqueous outflow system, and most recently anterior segment vessels. We also describe advancements in anterior segment OCT technology that have improved understanding with greater detail, such as tear film in dry eye disease evaluation, intra-operative real-time imaging for anterior segment surgery, and aqueous outflow with angle assessment for glaucoma. Improvements to image processing and software have also improved the ease and utility of interpreting anterior segment OCT images in everyday clinical practice. Future developments include refinement of assessing vascular networks for the anterior segment, in vivo ultra-high resolution anterior segment optical coherence tomography with histology-like detail, en-face image with 3-dimensional reconstruction as well as functional extensions of the technique.

Although adverse reactions to indocyanine green (ICG) are known to occur, the dye has been used for more than 30 years in tests of cardiac and hepatic function, with a high level of safety. Improved digital video technology has renewed interest in the use of intravenous ICG in ophthalmic imaging. This report describes the authors' experience regarding the safety of ICG for digital angiography and their recommendations for its use in the ophthalmic setting. Digital ICG videoangiography was performed in 1226 consecutive patients, and 1923 ICG videoangiography tests were performed. A registry of adverse reactions to ICG was established. Criteria were used to define mild, moderate, and severe adverse reactions, and these data were recorded for every ICG study performed. There were three (0.15%) mild adverse reactions, four (0.2%) moderate reactions, and one (0.05%) severe adverse reaction. There were no deaths. This study documents the safety of intravenous ICG for use in ophthalmic videoangiography.