Ooooh lovely. See complete abstract below for condensed version documentation of the age-old sign vs symptom discrepancy, from some of my favorite drs/researchers.
Jumping ahead to the conclusion, for those like me who are too lazy to read:
Conclusions: No consistent relationship was found between common signs and symptoms of DED.
How can we argue with that... supported, as it is, by everything from common sense to years of research and published studies (because let's be honest, for every study that purports to infallibly associate thus-and-such sign with any one or all symptoms, there's another that contradicts it).
Yet there are SO many things that OUGHT to be altered by accepting this as established fact or as good as.
For example... How can the FDA insist on improving both signs and symptoms to the extent they do, thus barring so many therapies that could help people with severe disease?
Or... Why must we continue treating people with few-to-no clinical signs but with severe pain or other symptoms as though they really did have severe dry eye when they don't, allowing or encouraging them to try every drug, device or surgery available, postponing the inevitable conclusion that there's nerve pain issues involved and re-directing their pursuits to palliative treatments till better able to diagnose & treat the real pathology?
And the list goes on. We know now and we always have known that signs and symptoms don't correlate. What are we going to DO about it, is what I want to know!
Correlations between commonly used objective signs andsymptoms for the diagnosis of dry eye disease: clinical implications.
Purpose: To evaluate the relationship between signs and symptoms of dry eye disease (DED) in a clinic-based population.
Methods: In a retrospective analysis, clinical signs and symptoms were evaluated for 344 subjects (n = 82, normal; n = 263, dry eye), across 11 sites from the EU and United States. Pearson correlations between signs and symptoms (r(2) ) and an independent components analysis (ICA) mixing matrix were derived from the data set. Similar analysis was performed on an independent data set from 200 subjects in a previous study in Munich, Germany.
Results: No correlations above r(2) = 0.17 were found between any signs and symptoms, except for corneal and conjunctival staining, which reported an r(2) = 0.36. In the multisite study, the average r(2) for osmolarity (0.07), tear breakup time (0.12), Schirmer test (0.09), corneal (0.16) and conjunctival staining (0.17), meibomian grading (0.11) and Ocular Surface Disease Index(®) (0.11) were consistently low. Among patients who showed evidence of DED by consensus of clinical signs, only 57% reported symptoms consistent with a diagnosis of DED. Similar results were observed in the Munich-based study data set. Each component of the ICA mixing matrix exhibited minimal residual information.
Conclusions: No consistent relationship was found between common signs and symptoms of DED. Each type of measurement provides distinct information about the condition of the ocular surface. These results also demonstrate that symptoms alone are insufficient for the diagnosis and management of DED and argue for a consensus of clinical signs that better reflect all aspects of the disease.
Acta Ophthalmol. 2012 Dec 28. doi: 10.1111/aos.12012. [Epub ahead of print]
Sullivan BD, Crews LA, Messmer EM, Foulks GN, Nichols KK, Baenninger P, Geerling G, Figueiredo F, Lemp MA.
TearLab Corporation, San Diego, California, USA Department of Ophthalmology, Ludwig Maximilian University, Munich, Germany Kentucky Lions Eye Center, University of Louisville, Louisville, Kentucky, USA College of Optometry, University of Houston, Houston, Texas, USA Royal Victoria Infirmary & Newcastle University, Newcastle Upon Tyne, England Department of Ophthalmology, University of Dusseldorf, Germany Department of Ophthalmology, Georgetown University, Washington, District of Columbia, USA Department of Ophthalmology, George Washington University, Washington, District of Columbia, USA.
p.s. THANK YOU to whoever typed and edited that abstract for putting spaces after the equal signs. Helps to not give my dinosaur blog display the verbal diarrhea these symbols tend to trigger.