EyeWorld Asia-Pacific March 2015 Issue

52 EWAP CORNEA March 2015 stroma relative to controls, and these changes varied based on the region of the cornea examined and the direction in which they were measured. Ion diffusivity increased in the x-y plane in crosslinked corneas relative to controls, according to Dr. Waring. This effect was most pronounced in the anterior stroma and decreased as stromal depth increased. In the z direction, conductivity decreased as stromal depth increased in crosslinked corneas compared to controls, indicating a corresponding decrease in diffusivity through the stroma. Hydration was not statistically significant between sample groups, so the observed effect is a true material property change, Dr. Waring explained. Clinical significance “Now we have a non- destructive ex vivo method that establishes that there is a material property change, that it’s anisotropic meaning it’s directionally dependent, that the change in diffusivity increases parallel to the collagen fibers, and it decreases orthogonal to the collagen fibers,” Dr. Waring said. Decreased transport through the stroma in the z direction makes sense, Dr. Waring said, but the observation that ions travel more readily in the x-y plane after crosslinking was at first counterintuitive and not fully understood. However, when correlated to immunofluorescent models, crosslinking’s “paradoxical diffusion effect” may make sense, and there are further studies ongoing to elucidate the findings. While other studies have shown that the mechanical effects of crosslinking are more pronounced in the anterior stroma, this is the first to show a similar effect on changes in diffusivity. Now that this method has been established, it can be applied to evaluate changes in the cornea in many other situations, said Dr. Waring. Next steps in his research involve correlating these results with the mechanical property changes currently underway and comparing the material property changes in response to different crosslinking protocols. Dr. Waring plans to investigate epi-on and other delivery methods, varying irradiation parameters, the effects of oxygen and dextran, and more. This data could then be used to optimize the crosslinking procedure to achieve the desired mechanical and material property outcomes. “We can compare various parameters to optimize the effect of crosslinking from an efficacy standpoint in a bench setting,” Dr. Waring said. “In addition, we are learning more about the true mechanism behind crosslinking and how it affects the cornea.” EWAP Editors’ note: Dr. Waring has no financial interests related to his comments. Contact information Waring: georgewaringiv@gmail.com a rheumatologist because of the burden associated with the transfer of care. The process was much more cumbersome and created a level of anxiety and degree of inconvenience to the patient. Now we are able to accurately detect Sjögren’s in-house, which enables the patient to transfer to a rheumatologist or a primary care doctor with critical information already in hand. Our rheumatology colleagues are fairly impressed with our ability to initiate diagnostic testing for Sjögren’s syndrome and serve as a catalyst for appropriate care. A sample case To give you an example of how we use such testing methods to our advantage, here is a sample case. A 67-year-old female patient was referred to our practice for cataract evaluation. In addition to a generalized decline in visual function, she was experiencing intermittent ocular surface irritation and intermittent worsening of vision when working on the computer. While sitting in the exam chair she was noted to be chewing gum, which is sometimes evidence of self-management of xerostomia. Her Ocular Surface Disease Index (OSDI) score was 34. She demonstrated clinical symptoms that are suggestive of Sjögren’s syndrome. We conducted dry eye diagnostic testing, which revealed a homeostatic lack of stability between both eyes when tested with the TearLab Osmolarity Test (TearLab, San Diego), and subsequent InflammaDry confirmed elevated MMP-9. We also conducted the Sjö test, which indicated that this patient was likely to have Sjögren’s syndrome. These results allowed us to target therapy with topical steroids and institute topical cyclosporine along with nutritional supplements. We then coordinated with the patient’s primary care physician and followed with a referral to a rheumatologist, all prior to surgical management of the cataract. Benefit of testing Efficiency in a practice is only as good as what we can offer patients. Understanding how diagnostic testing works and how to apply the technology is where its value lies. I recommend that physicians looking to implement diagnostic technologies in their practices conduct research themselves. Take the time to educate staff so they understand the value of these tools and have a vested interest in the process. Also, I recommend that you utilize the representatives of each of the companies and allow this teamwork philosophy to take its course, offering patients a clear understanding of the added value of each test. We pride ourselves in providing the best possible management and making our practice a center for innovation by delivering ophthalmic diagnostic technology that broadens our ability to diagnose efficiently and allows for specific, targeted care for our patients. EWAP Reference 1. Liew M, Zhang M, Kim E, et al. Prevalence and predictors of Sjögren’s syndrome in a prospective cohort of patients with aqueous-deficient dry eye. Br J Ophthalmol . 2012;96: 1498–1503. Editors’ note: Dr. Solomon is the surgical and refractive director at Solomon Eye Associates Physicians and Surgeons, and principal investigator at Bowie Vision Institute (Bowie, Md). He has financial interests with Rapid Pathogen Screening. Contact information Solomon: jdsolomon@hotmail.com Embracing - from page 50 Study - from page 51