BLOG: Evolution of diagnostics and imaging in glaucoma

The main goal with glaucoma is detecting and assessing risk as early as possible. While most technologies will reveal an issue eventually, the earlier a pathology is discovered, the more sight is preserved. When it comes to structural testing, technology continues to improve, bringing with it higher resolutions and improved information with normative databases. Functional testing is also becoming more available, filling in a gap in our understanding of the target for glaucoma diagnosis and treatment.

There has been a significant shift in what is important to follow structurally over the last decade or so, not only because emerging technology now allows for better diagnostics, but because of our improved understanding of how to obtain earlier disease detection. Adjunctive tests such as corneal hysteresis, along with other technologies, are a good way to assess risk as they provide different types of information along with the structural testing. It is also becoming standard to image the retina and ganglion cells, which is a shift from the traditional process of scanning the optic nerve. Continuous improvements to OCT now allow for enhanced scans of the nerve fiber layer around the optic nerve, along with scanning the macular region to assess retinal ganglion cells. As early-stage glaucomatous damage is primarily located in the macular region, obtaining accurate, informative and high-quality scans is greatly beneficial.

Visual fields technology is, in my opinion, the biggest barrier in clinical care, both on the side of the doctors and the patients. The results are subjective, and patients report disliking this test the most. This is where visual electrophysiology fills a need, both in terms of ease of use and in earlier detection of dysfunction. This is especially true when using pattern electroretinography (PERG) with the Diopsys Nova ERG and VEP vision testing system for glaucoma patients. The PERG testing detects early signs of disease through concentrating on the amplitude and latency responses of the retinal ganglion cells. This aids in differentiating between patients who have healthy cell response vs. those who are in early stages of the disease. When used in combination with other technologies, it can be utilized as a tiebreaker, often substantiating suspected problems or determining if suspicions were unfounded. It is both complementary to testing we already perform while offering different and improved technology that provides disease detection in some cases years earlier than other functional technology.

Reference:

Banitt MR, et al. Invest Ophthalmol Vis Sci. 2013;doi:10.1167/iovs.12-11026.

Robert J. Noecker, MD , is a leading ophthalmologist with more than 15 years developing innovations in glaucoma surgery. He currently practices with Ophthalmic Consultants of Connecticut and is on the clinical faculty at Yale University. Noecker can be reached at email: noeckerrj@gmail.com.

Disclosure: Noecker reports he is a consultant for Alcon, Aerie, Alimera, Beaver-Visitec, Diopsys, Ethis Communications, Glaukos, InnFocus, Inotek, Iridex, Novartis, Ocular Therapeutix, Omeros, PolyActiva, Santen, Shire, Solx and Sun Pharmaceuticals; is a speaker for Alcon, Allergan, Beaver-Visitec, Diopsys, Imprimis, Iridex, Novartis and Quantel; does research for AqueSys, Glaukos and InnFocus; and has an ownership interest in Ocular Therapeutix, Tula Medical and ISP Surgical.