EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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March 2013 by "When clinical differential diagnosis of ocular surface lesions was broad, UHR OCT images provided optical signs indicating a more specific diagnosis and management," investigators wrote. In a few of the lesions, OCT identified an incorrect initial clinical diagnosis. The study investigators concluded that UHR OCT can be a helpful and noninvasive adjunctive diagnostic method. Presented at the Cornea Society/ Eye Bank Association of America Symposium in Chicago in November 2012, research led by Fouad El Sayyad, M.D., Bascom Palmer Eye Institute, found that OCT is a useful and noninvasive technique to diagnose ocular surface lesions. The study found that OCT is particularly useful for a better view of OSSN, Dr. El Sayyad said. The group also found the technology helped view tumor resolution with topical chemotherapy. Dr. Fraunfelder said that OCT's advantage lies in its ability to provide more detail than other types of imaging. "Ultrasound does not permit the degree of resolution and magnification that OCT does. Slit lamp photos do not allow for imaging of deeper eye structures and the tumor morphology beneath the surface," he said. The use of UHR OCT makes it possible to perform an "optical biopsy," said Jianhua Wang, M.D., associate professor of ophthalmology, Bascom Palmer Eye Institute, lead investigator of a 2011 review article in Ophthalmic Surgery, Lasers & Imaging on OCT for the anterior segment. Dr. Wang and co-authors noted that UHR OCT has been used since 2008 to evaluate the ocular surface of all patients seen at Bascom Palmer's Ocular Surface and Inflammation Service. "Using the anterior segment UHR OCT to evaluate the ocular surface has been a critical tool to diagnose and monitor responses to therapies of diseases of the cornea," he said. Particularly, the ability to evaluate the corneal surface with a 3-micron resolution helps clinicians make in vivo microscopic-like evaluation of corneal structures. Esen K. Akpek, M.D., associate professor of ophthalmology and rheumatology, and director, Ocular Surface Diseases and Dry Eye Clinic, Wilmer Eye Institute, Johns Hopkins University, Baltimore, finds OCT helpful to study the tear film in dry eye patients. She believes OCT will provide greater clinical and precise visual insight in the diagnosis and monitoring of ocular surface lesions, leading to better treatment approaches. Limitations, future avenues However, the technology still has its limits. "The magnification is limited, as is the depth of the imaging. We cannot see all the way into the eye, and we cannot see individual cells as much as we would like," Dr. Fraunfelder said. Additionally, use of the technology does not necessarily change the course of treatment. "We still remove eye tumors that have dysplastic characteristics, and we still observe lesions that appear benign," Dr. Fraunfelder said. When a patient has a large lesion or keratin, there can be shadowing, Dr. Karp said. Additionally, keratin on the ocular surface can block the attainability of accurate images, she added. OCT also comes with an additional cost, Dr. Karp said. In the future, the ability to use OCT imagery to diagnose tumors instead of performing surgeries on questionable tumors would be ideal, Dr. Fraunfelder said. "For instance, if we could tell through blood vessel patterns or other characteristics that primary acquired melanosis has no atypical cells within the patch of conjunctival pigmentation, then we would not need to perform an excisional biopsy. We could just observe," he said. Other future advances should include greater resolution and improvement of lateral resolution so users can view structures at the cellular level, Dr. Wang wrote in the review article. EW Curved capsulorhexis forceps, cystotome teeth, fits through 1.8 mm incision The same great performance for less pe formance High quality reusable ophthalmic surgical instruments eusable su gical Surgical stainless steel tips and durable handles made gical of a composite polymer Performance equivalent to the best conventional, allmance metal instruments Eliminate time and expense of dealing with misaligned, bent, damaged, or lost instruments Editors' note: The physicians have no financial interests related to this article. Contact information Akpek: 410-955-5214, esakpek@jhmi.edu Fraunfelder: 503-494-7674, fraunfer@ohsu.edu Karp: 305-326-6156, ckarp@med.miami.edu Wang: 305-482-5010, jwang3@med.miami.edu 1-800-441-1314 • moria@moriausa.com • www.moria-surgical.com www w