Eyeworld

continued from page 3 Figure 3. Increasing glaucomatous damage patient is healthy. In this instance, any of the newer technologies would have been helpful, including the HRT and SITA SWAP, both of which confirmed this patient was healthy. Treatment intensity The stage of the disease should be the determining factor in how in- tensively to treat. There does not necessarily need to be the same target pressure for both eyes. Determine first if there's a change. Figure 3 shows a patient who has an increase in the optic nerve cupping, with an increased corresponding visual field and OCT. This particular patient had time-domain OCT and then we moved to SD-OCT. The technology behind OCT itself is not patented, so there are numerous manufac- turers of OCT machines, among them Heidelberg, Nidek, Opt- ovue, Optos, Topcon, and Carl Zeiss Meditec. Each system has its own benefits and differentiat- ing factors, and each has its own set of enhancements unique to the developer/marketer. Overall, however, OCTs boast progression analysis, structural analysis, gan- glion cell analysis, and eye track- ing capabilities, and the devices can eliminate static in images to reveal the finer details in the retinal layers. Visual field testing While OCT has vastly improved our ability to diagnose and manage glaucoma, we cannot overlook the importance of visual field testing. The published literature supports this—in the randomized, prospective, con- trolled trials, once there's mild to moderate glaucoma, progression has almost always been detected by visual field changes. The threshold of utility for OCT mea- surement of retina NFL (RNFL) thickness has been reported to be 75 micromillimeters, and somewhere around 50–55 mi- cromillimeters OCT is no longer able to measure change in RNFL thinning, but visual fields are still useful. 4 In advanced glaucoma, OCT may no longer be helpful; this is typically where clinicians will rely upon visual field testing. As visual field analyzers con- tinue to improve incrementally, a good diagnostic performance can be obtained with optimized subsets of the standard 24-2 test pattern 5 ; once you get to 30 de- grees, you'll get more artifactual error that is not glaucoma. References 1. Sharma P, Sample PA, Zangwill LM, Schuman JS. Diagnostic tools for glau- coma detection and management. Surv Ophthalmol. 2008;53 Suppl1:S17–32. 2. Medeiros FA, Lisboa R, Weinreb RN, et al. A combined index of structure and func- tion for staging glaucomatous damage. Arch Ophthalmol. 2012;130(9):1107–16. 3. Malihi M, Moura Filho ER, Hodge DO, Sit AJ. Long-term trends in glaucoma-related blindness in Olmsted County, Minnesota. Ophthalmology. 2014;121(1):134–41. 4. Bussel II, Wollstein G, Schuman JS. OCT for glaucoma diagnosis, screening and detection of glaucoma progression. Br J Ophthalmol. 2014;98 Suppl 2:ii15–9. 5. Wang Y, Henson DB. Diagnostic perfor- mance of visual field test using subsets of the 24-2 test pattern for early glaucoma- tous field loss. Invest Ophthalmol Vis Sci. 2013;54(1):756–61. Dr. Rhee is professor and chair, Department of Ophthalmology & Visual Sciences, University Hospitals Eye Institute, Cleveland, Ohio. He can be contacted at 216-844-8590 or dougrhee@aol.com. Figure 1. Initial images and visual fields for 64-year-old male of African descent 64-year-old man African descent + family history 23 mm Hg CCT 590 µm 22 mm Hg CCT 605 µm Figure 2. Time-domain optical coherence tomography image of the same patient Supported by unrestricted educational grants from Aerie, Alcon Laboratories, Allergan, Carl Zeiss Meditec, and Glaukos 5

• Cover
• _GoBack
• _GoBack (1)