Dry Eye Disease: Time to Introduce Ocular Surface Stress Tests?

Abstract

The absence of correlation between patient symptom experiences and observed clinical signs together with the onset of the digital screen revolution has triggered a renaissance in interest in the causes of eye strain or fatigue in both health and disease. In this issue, Karakus et al1Karakus S. Agrawal D. Hindman H.B. et al.Effects of prolonged reading on dry eye.Ophthalmology. 2018; 125: 1500-1505Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar (see page 1500) rise to the challenge by interrogating the impact of prolonged sustained silent reading in healthy individuals and those with a diagnosis of dry eye using the Tear Film and Ocular Surface Society Dry Eye Workshop II cardinal parameters for triaging activity and damage. Activity and damage indices are essential for diagnosis, monitoring, defining, and predicting the relapse, remission, and progression of disease, in addition to providing clear consistent documentation of treatment response vital for ensuring robust end points or outcomes for small- and large-scale trials of novel healthcare technologies.2Mathewson P.A. Williams G.P. Watson S.L. et al.Defining ocular surface disease activity and damage indices by an international Delphi consultation.Ocul Surf. 2017; 15: 97-111Crossref PubMed Scopus (8) Google Scholar This is compounded by the discrepancy between severity of signs and symptoms, specifically those cases with dry eye disease in which severity of dry eye produces diminished corneal sensation, or conversely those patients who report disabling dry eye symptoms with minimal or no examination findings (corneal neuropathic pain). Time trade-off and standard gamble methods indicate the impact of moderate-to-severe dry eye disease to be similar to that of renal dialysis and severe angina leading to significant anxiety and depression.3Buchholz P. Steeds C.S. Stern L.S. et al.Utility assessment to measure the impact of dry eye disease.Ocul Surf. 2006; 4: 155-161Crossref PubMed Scopus (120) Google Scholar Similarly, healthy individuals increasingly report ocular fatigue or dry eye symptoms after prolonged visual tasks. The emergence of a body of work confirming the negative impact of 3-dimensional displays on eye fatigue using sophisticated multimodal readouts such as electroencephalograms; eye-blink rates detected through remote gaze-tracking systems with high-speed, mega-pixel cameras; and facial temperature readings using thermal cameras before and after visual tasks,4Bang J. Heo H. Choi J.-S. Park K. Assessment of eye fatigue caused by 3D displays based on multimodal measurements.Sensors. 2014; 14: 16467-16485Crossref PubMed Scopus (44) Google Scholar together with standardized ocular challenge (by regulation of humidity, temperature, airflow, lighting conditions, and visual tasking) presented as the Controlled Adverse Environment (CAE, Ora, Inc., Andover, MA) are paving the way for the introduction of ocular surface stress tests in the clinic. Karakus et al use the self-administered Ocular Surface Disease Index (Allergan, Inc., Irvine, CA) in their study design, followed by a battery of ocular surface function tests, including noninvasive tear-film break-up time, surface irregularity indices, Schirmer’s test without anesthetic, and interestingly, a detailed composite breakdown of the ocular staining score into temporal and nasal conjunctival staining scores (maximum 3 points each), corneal staining score (maximum 3 points), and corneal modifier scores (1 point each for central staining, confluent staining, and presence of filaments).5Whitcher J.P. Shiboski C.H. Shiboski S.C. et al.A simplified quantitative method for assessing keratoconjunctivitis sicca from the Sjögren’s Syndrome International Registry.Am J Ophthalmol. 2010; 149: 405-415Abstract Full Text Full Text PDF PubMed Scopus (299) Google Scholar This deconstruction of the Ocular Staining Score5Whitcher J.P. Shiboski C.H. Shiboski S.C. et al.A simplified quantitative method for assessing keratoconjunctivitis sicca from the Sjögren’s Syndrome International Registry.Am J Ophthalmol. 2010; 149: 405-415Abstract Full Text Full Text PDF PubMed Scopus (299) Google Scholar parameters has been critical in their findings that the ocular surface stressed by undertaking a validated reading task unmasks clinical signs not seen in the resting state. These data have broader ramifications and could cast doubt on the failure of innovative technologies obtaining regulatory approval for the management of ocular surface disease, because benefits may have been undermined in the clinical trial design by not capturing the putative positive outcome of reduction of ocular surface damage after a reading task. Although Karakus et al present a relatively small study and further studies are required, the authors raise the profile of accurately staging and scoring dry eye using inexpensive tests, specifically using conjunctival and corneal staining scores, and go some way to endorsing the concept of introducing prolonged reading as a simple ocular surface stress test (Fig 1), not only in the clinical setting, but also within the clinical trials arena. Effects of Prolonged Reading on Dry EyeOphthalmologyVol. 125Issue 10PreviewTo demonstrate the effects of prolonged silent reading on tear film and ocular surface parameters. Full-Text PDF