Dry eye in turn can complicate care of glaucoma, because it interferes with the reliability and reproducibility of visual field tests, optical coherence tomography, and topographical measurements for cataract surgery.
Tear film is the first refractive interface, he said. And the anterior surface of the precorneal tear film has the greatest optical power of any ocular surface.
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But more glaucoma treatments have become available that avoid causing dry eye, such as microinvasive glaucoma surgery (MIGS) and selective laser trabeculoplasty.
In addition, new intracameral drug delivery systems have become available that can also avoid dry eye as a side effect.
And dry eye treatments have gotten better, too. Dr. Lewis helped test TrueTear, a device that is inserted into the nose to stimulate nerves that trigger tear production, much in the way cutting onions causes tearing.
“This is a concept that I’m really exciting about,” Dr. Lewis said. “Patients refused to give the device back. This will transform the treatment of dry eye.”
A similar principle—neurostimulation—is being used in other conditions, including Parkinson’s disease, he said.
Dry eye diagnostics are also improving, Dr. Lewis said, but he still considers tear breakup time the most useful.
If glaucoma specialists need any other guiding principle when faced with dry eye, they should consider the principle “do no harm,” he concluded.