BLOG: Evidence-based medicine: Increasing value through early diagnostics

The seemingly constant stream of new products and devices being released for surgery, diagnostics and new therapies makes it an exciting time for ophthalmology. While it can be a bit overwhelming at times, these new technologies enable us to provide better care for our patients. Diagnostics especially facilitate improved outcomes by allowing us to pinpoint issues early enough to prevent permanent damage and treat with solid evidence-based therapies.

For glaucoma, traditional treatment arcs have been a bit backward. We would administer tests such as visual fields and then wait and watch, withholding treatment until structural damage could be determined, although by then it was already too late and permanent damage had occurred. Now we have diagnostics that detect dysfunction early enough for intervention while there is still time to prevent irreversible damage. While the causes of glaucoma are vast, the treatment is similar: lower the pressure. However, what works for one patient will not necessarily work for another. With improved diagnostics, we can better determine if there are other underlying issues or causes, which allows for more appropriate treatment based on the evidence gleaned during testing.

I still utilize visual fields tests because they are the gold standard and they provide valuable information. However, the three new diagnostics that have made the most significant difference in helping me identify at-risk patients and determining treatment therapies for early glaucoma are: measuring the corneal hysteresis, measuring the retinal ganglion cell layer and measuring pattern ERGs for glaucoma suspects.

Corneal hysteresis — the difference between the pressure at which the cornea bends inward and outward again — is measured with the Reichert Ocular Response Analyzer tonometer. This test helps determine which patients are more at risk for disease progression and which may respond more favorably to topical medications. I have found it to be a more accurate measure of IOP than our traditional means of measuring.

Obtaining a detailed retinal ganglion cell (RGC) analysis with OCT allows us to detect early disease as it scans the macula vs. the optic nerve. The macula is more consistent between individuals, whereas the optic nerve can appear different depending on the patient population being tested. In the past, I have performed OCT testing and obtained normal results only to perform a RGC analysis and detect early disease. The technology driving OCT is continuously improving, as is the way in which we examine the data obtained. With each improvement, our ability to treat early disease increases exponentially.

Electrophysiological testing of the retina and neuro-visual pathways has been significantly beneficial in accurately detecting disease well before the capabilities of traditional testing. By performing pattern electroretinography testing with the Diopsys Nova ERG and VEP Vision Testing System, we can now detect issues long before any permanent damage occurs. This gives us the opportunity to confidently provide evidence-based treatment while there is still time to prevent, and in some cases even reverse, damage to the nerve. I perform this testing for all patients suspected of having glaucoma, even if they register normal visual fields. The accurate and objective results have allowed us to reclassify patients and provide more appropriate treatment.

Another disease with significant advancements in diagnostics and treatment is ocular surface disease (OSD). OSD trickles down to every other aspect of eye care, and the state of the ocular surface can have an enormous impact on how other therapies work. However, in the past it was difficult to find a test that would yield accurate and consistent results. The Schirmer’s test is extremely variable, and dyes can be subjective. Now, we have access to more quantitative tests that can be of real benefit to people with OSD such as tear osmolarity testing and testing for the inflammatory biomarker MMP-9 with InflammaDry (RPS).

Along with tear osmolarity testing, imaging the meibomian glands with LipiView (TearScience) not only enables us to make a more accurate diagnosis and provide more appropriate therapies, it also engages the patients in their own treatments. Being able to see the issues for themselves and track their numbers provides better peace of mind and encourages patient compliance, which in turn aids in improved outcomes.

All of these diagnostics have made a significant difference in treating patients. Using objective diagnostics and our own subjective impressions brings the art of medicine into our practices. The ability to diagnosis disease earlier and prescribe the most accurate and appropriate evidence-based therapies positions us to provide the best possible care for our patients.

Robert J. Noecker, MD , MBA, 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