May 20, 2019
5 min read

Enter the whales, part 1

The AAO dry eye Preferred Practice Pattern is reasonable and approachable.

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Apropos of nothing, there is a torrential downpour outside my window as I sit down to write this column. It always seems to rain when I write about tears. Odd, no?

Individuals who saw a problem and sought a greater understanding of its origins originally populated our great ocean of dry eye disease care. Dr. Michael Lemp would certainly be Poseidon in this epic tale. His lineage would travel through the “shark family” lines of the likes of Dr. Gary Foulkes and Dr. Hank Perry on through to Drs. Eric Donnenfeld, Ed Holland and Marguerite McDonald, among others. “Schools” that brought together broader lines of thought in the diagnosis and treatment of DED followed these and other singular leaders. Here I think of TFOS and the DEWS reports and the CEDARS group with its diagnosis-driven treatment algorithms.

I consider these two the fusiliers and barracudas of the DED world, respectively.

And now the blue whale has arrived. Did you know that the American Academy of Ophthalmology has a DED Preferred Practice Pattern? No? Neither did I. In general, I am no fan of the whole PPP program. Most are written by cloistered academics who are totally removed from the reality of ophthalmology as it is practiced outside of the ivory tower. That, or super subspecialists whose viewpoint is so narrow that it cannot be applied outside the parameters of a randomized controlled clinical trial. This kind of disconnect can contribute as much harm as it provides help. Example: While AAO declares that PPPs “are not medical standards to be adhered to in all individual situations,” OMIC openly calls them “standards of care.”

Having said this, the AAO dry eye PPP is actually a reasonable entry-level document for those who want to swim into the DED space. Credit for this probably goes to PPP committee member Francis Mah. Francis is a kind of unicorn in our world. An acknowledged academic of some distinction, he is also a pragmatic frontline practitioner who spends a significant proportion of his time in the act of providing actual care to actual patients. Michelle Rhee is also on the panel and can be described the same way. Accordingly, this is a rather conservative document that is nonetheless helpful and positive in its approach to the diagnosis and care of patients with DED.

This particular PPP starts out like pretty much all the others with a discussion of the prevalence and scope of the DED problem. Like so many other academic treatments (and FDA-monitored educational programs), the journal citations vastly under-call the true incidence of DED in the wild. Nonetheless, we are reminded that DED is a growing problem somewhat more common in women, with increasing frequency as we age. There is a note about the chronic, relapsing nature of DED and an acknowledgement that severity increases over time if it is not treated. A particularly welcome observation is made about the disconnect between signs and symptoms. “[C]hronic therapy and patient compliance are necessary in most instances.”


Because this was researched and published in 2018, DEWS II was available to the authors as a source. Hence, the now-established primacy of inflammation on the surface of the eye is noted as a driver in the pathogenesis of DED. Like all other reviews and treatment programs up to this point, the AAO PPP also declines to make a definitive statement as to whether this inflammation is chicken or egg, saying only that it “plays a role.”

As with many of the other PPP topics covered, the DED PPP is particularly strong in its sections on associated conditions. We see some of the traditional causes (eg, Sjögren’s syndrome), more recently emphasized comorbidities (eg, rosacea), and a nod to the modern scourge of radically increased screen time and its effect on dry eye in both adults and children. The impact of the highly specialized viewpoint of Dr. Esen Akpek of Wilmer is seen in the attention paid to the impact of Sjögren’s both from a dry eye standpoint as well as the general medical realm; we are reminded of the importance of testing for this diagnosis because at least 5% of these patients will develop a lymphoid malignancy. It is not often that a DED doc gets to save a life. We see these folks first so often that we have an opportunity to initiate the inquiry.

Speaking of testing, the PPP is reasonable about our point-of-care tests, including Sjö (Bausch + Lomb), in the pursuit of making the DED diagnosis and choosing treatment. MMP-9 as tested with InflammaDry (Quidel) gets a mention, if faint praise, in that it “may aid in the management.” On the other hand, tear osmolarity (TO) gets quite a bit of airtime and very fair and favorable treatment. While it does not lay out any specific suggestions as to how TO should be used in treating DED, the PPP is supportive of TO as a clinically significant measurement of the loss of homeostasis that is present on the surface of the eye in both aqueous deficient and evaporative DED. Consistent with the guidance provided by yours truly and other long-time DED docs, this review suggests that TO is best used in the context of and alongside a classic history and clinical exam (hat tip: Jodi Luchs).

The AAO is an organization of and for eye surgeons, so it should be no surprise that the effect of DED on surgery and surgical outcomes is emphasized. Laser refractive surgery, in particular LASIK, can cause a worsening of pre-existing DED. While dry eye symptoms are common postop, they tend to subside over time. “[If] a pre-existing dry eye condition can be improved preoperatively,” patients can safely undergo LASIK per our most conservative professional organization’s guidance. In a similar fashion, the need to evaluate cataract patients for the signs and symptoms of DED before cataract surgery is stressed in order to predict patients at risk for postop dryness issues. Heaven only knows how often DED is the cause of a dissatisfied postop cataract patient.


Let me finish with a few words about DED treatment. Unlike the CEDARS protocols, the AAO dry eye PPP breaks no new ground when it comes to the nuts and bolts of treating this disease. Management guidelines are simply brought forward from DEWS II and then extensively supported with numerous literature citations. While it dances around the question of whether or not the use of omega-3 fatty acids is helpful, the PPP is firm in its conclusion that anti-inflammatory treatment with cyclosporine A, lifitegrast and topical steroids has a significant beneficial effect on both the objective and subjective outcomes in DED. Again, numerous studies are cited in which this treatment effect is conclusively demonstrated. In my opinion, this renders the inexplicable Seitzman editorial in the February Ophthalmology moot.

Don’t these AAO folks read their own stuff?

The blue whale in the DED ocean has arrived on the scene. Of the three major dry eye opuses now in circulation, the AAO Preferred Practice Pattern is the most approachable, especially if you are new to the field. DEWS II is certainly the most comprehensive (4,900 pages!*). The CEDARS paper provides something closer to an instruction guide to building an individual patient’s treatment. The American Society of Cataract and Refractive Surgery is the orca of the eye world, and it is about to make a splash as we peel back the curtain on the ASCRS DED treatment algorithm presented by Chris Starr and colleagues in San Diego.

*Just kidding.

Disclosure: White reports he is a consultant to Allergan, Shire, Sun, Kala, Ocular Science, Rendia, TearLab, Eyevance and Omeros; is a speaker for Shire, Allergan, Omeros and Sun; and has an ownership interest in Ocular Science and Eyevance.