Larry Alexander, OD, is senior director clinical education, at Optovue. A 1971 graduate of Indiana University School of Optometry, he served in the U.S. Navy before accepting a position as a professor at the University of Alabama Birmingham School of Optometry. He has published three editions of Primary Care of the Posterior Segment as well as contributed to the professional literature. He has also lectured extensively in the area of ocular and systemic disease. Clinical editor for the Optometry and Vision Science journal of the American Academy of Optometry, Alexander was recently honored with the inaugural Indiana University Distinguished Alumni Foley House Award.
Richard Clompus: OCT has made a dramatic change in the delivery of optometric eyecare. Spectral Domain Optical Coherence Tomography (SD-OCT) provides a truly unique assessment of ocular tissues. The technology is the gold standard for diagnosing and managing glaucoma, with Optovue a key player in the category with its iVue SD-OCT device. How does this technology provide such detailed views of living microscopic structures?
Larry Alexander: SD-OCT is based on the principle of light passed into the eye and reflected back (echoes) by anatomical structures to sensors within the instrument. The data gathered is both quantitative and qualitative and is rapidly analyzed by the software to provide on-screen images and printable reports. The non-invasive technology gives high-resolution cross-sectional images of retina, vitreous, choroid and optic nerve structure in seconds. En Face (face down) manipulation of the b-scan image allows in-depth layer-by-layer analysis.
RC: How has this technology impacted primary care optometry?
LA: It has provided the opportunity to see alterations in the eye that are often not visible by standard fundus evaluation technology. SD-OCT has created an “epidemic” of vitreo-macular adhesion by revealing what we have never seen before. We can now detect ocular disease at a much earlier stage and intervene to minimize vision loss. SD-OCT has also streamlined ocular health care delivery by minimizing unnecessary referrals. We now have a very effective method to quantify progression and regression of disease-related issues.
RC: Can you share applications of using SD-OCT to examine the anterior segment of the eye?
LA: SD-OCT has revolutionized analysis of the anterior segment of the eye. Clinicians now have a very accurate way to see the relationship of contact lenses (especially therapeutic hybrid lenses) to the corneal surface, enabling a better fit. It also helps answer issues such as the depth of an abrasion, presence of a penetrating wound, presence of retained foreign bodies, progression of ulcers and the true anatomy of the anterior chamber, as well as giving non-contact pachymetry readings.
RC: What’s next for SD-OCT? Where will this technology take us as clinicians?
LA: This is a tough question as there are so many potential directions. The easy answer is the application of SD-OCT to retinal, optic nerve and choroidal vascular perfusion””not replacing fluorescein angiography but complementing it. That technology is real and being used internationally. I believe, however, that there is a plethora of information locked up in each scan obtained. It is quantitative information that is easily manipulated to unlock better methods of early diagnosis. All of the SD-OCT instruments have this type of data that can be isolated and analyzed in more efficient ways. Improved statistical analysis of current data should be a high priority, with a focus on the evolution of analytical in the future. OO