If we look at Fig 23 for the suggested diagnostic approach, we can identify the areas where DOs can have a vital part to play. Triaging questions, analysis of risk factors, symptomology, and of course advice on management including nutrition.
Fig 2. Recommended diagnostic approach for DED8.
The first part of the TFOS recommended diagnostic process is triage, this will help differentiate potential of DED from other OSD or conditions which may mimic DED. The triaging questions are questions which might normally be part of gathering history and symptoms during an eye examination or contact lens consultation but that does not limit their use to the consulting room. Understanding this information requires the right type of questions:
These questions should be combined with an assessment of various risk factors, as described in the section on prevalence and epidemiology.
The next step is to assess the level of symptoms and to do this one of two recognised questionnaires are recommended,8 the Ocular Surface Disease Index (OSDI) or the Dry Eye Questionnaire (DEQ-5). (Fig 3)10,11
Fig 3 Symptomology questionnaires10,11.
From Ocular Surface Disease Index (OSDI) created by the Outcomes Research Group at Allergan Inc
Both questionnaires are robust and reliable but offer a different level of insight into the condition. The DEQ-510 is more simplistic, asking for symptoms on a typical day in the last month, whereas the OSDI11 offers insight into interpretation, level of severity and sub-grouping and reviewing symptoms over the previous week. It is also available as an app on mobile devices which does the slightly complicated calculation for you or your patient.
The cut off scores for these are 13 for OSDI and 6 for DEQ-5, a score equal to or higher indicates a positive result of symptoms of DED. A positive score in either of these should next lead to a more clinical investigation of homeostasis markers, or signs.
The conduction of tests for assessing these homeostasis markers falls outside of the remit of the DO however it is important that the supporting role of the DO covers the understanding of these tests and their results. A CLO/ESCLO may well get involved with conducting these tests where suitably competent.