An examination of the poor correlation between symptoms and signs of dry eye disease

ABSTRACT

Introduction

This review examines how mechanisms that are not related to tear dysfunctions may contribute to the development of symptoms of dry eye disease and help to explain why dry eye symptoms do not correlate with signs. Consideration is also given to the significance of tear deficiencies which cannot contribute to an examination of symptom-sign correlation.

Areas covered

Tear deficiencies which are not routinely assessed include inflammation, mucin quantity and quality, as well as corneal neuropathy and blink inefficiency.

Expert opinion

Tear deficiencies detected in an examination of patients reporting symptoms of dry eye disease become the targets for remedial approaches but not always with satisfactory outcomes. Other possible influences on symptoms could include genetic predispositions, sex, ethnicity, race, health literacy, mental health conditions, lower perceived health-related quality of life, and psychological factors. However, these possible influences cannot be assessed in most dry eye disease clinical settings. Consequently, too often symptoms of dry eye cannot correlate with signs of tear dysfunction that are not identified (and so not treated). Consequently, noncompliance with treatment recommendations may not be relevant to the persistence of symptoms or signs when treatment does not address tear dysfunctions which are difficult to assess.

KEYWORDS:

• Dry eye disease
• symptoms
• signs
• tear deficiencies
• correlation

Article highlights

• The often-reported lack of correlation between symptoms and signs of dry eye disease does not appear to have been explained satisfactorily previously.

• A barrier to satisfactory explanations might be the assumption that all dry eye symptoms are responses to one or more aspects of tear dysfunction which, for example, increase evaporative loss of aqueous, shorten tear breakup times, increase osmolarity, damage corneal and conjunctival epithelium and initiate inflammatory responses.

• However, this review considers tear dysfunctions which may produce, or help to produce, symptoms and signs of dry eye but for which clinical assessment is limited.

• This review also examines the possibility that several influences on symptoms of discomfort/pain which are unrelated to tear dysfunctions, but which are known contributors to the symptoms of other diseases and so could also be involved in exacerbating dry eye symptoms.

• This review finds that the examination of the correlation between symptoms and signs of DED is limited by many of the potential causes of dry eye symptoms (which are usually not identified in clinical settings) being unknown, and this deficiency in knowledge of these independent variables appears to explain the lack of correlation between signs and symptoms that has been reported previously.

• In addition, some contributions to dry eye symptoms are unrelated to tear deficiencies which further undermines any correlation between the signs and symptoms of DED.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or material discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or mending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Data availability statement

Blink exercise handouts and patient instruction slides are freely available on request from [email protected].

Additional information

Funding

This paper was not funded.