The report of the National Eye Institute/Industry Workshop on Clinical Trials on Dry Eyes proposed the first definition of DED in 1995, and the presence of symptoms were required in that definition.
7 Although this requirement was absent from the Japanese definition of DED in 1995,
50 the Japanese Dry Eye Society modified the definition and diagnostic criteria of DED, incorporating symptoms in 2006.
51 Thus, a reliable assessment of the symptoms has also become necessary for the diagnosis or evaluating the therapeutic effects for DED in Japan. In addition, the Japan Dry Eye Society proposed in “Definition and Diagnosis of Dry Eye in Japan, 2016” that DED be defined as a “combination of symptoms and an unstable tear film.” Information on these items were sufficient to make a definitive diagnosis of DED.
19 Thus, the assessments of symptoms are fundamental in DED for diagnosing and monitoring the therapeutic effects of any type of treatment.
The OSDI and the VFQ-25 have been used to measure the severity of the DED and as patient-reported outcomes in clinical trials and clinical studies in Japan. However, the terminology varies with the language and between different cultures and lifestyles.
25,28
The VFQ-25 is probably the most widely used questionnaire in the ophthalmic field that assesses the visual function and vision-related QOL, even though it is not a disease-specific questionnaire.
23–25 The VFQ-25 has been translated into other languages, including Italian, French, German, Spanish, Turkish, Chinese, Greek, Portuguese, Arabic, and Serbian.
52–59 In response to the need for evaluating vision-related QOL in the Japanese, a Japanese version of the NEI-VFQ-25 was developed in 2005.
25 Because the VFQ-25 is not a dry eye–specific questionnaire, the OSDI has been often used to measure the severity or QOL in DED as a validated DED-specific questionnaire. However, there are different diagnostic criteria in different countries, especially between Japanese Dry Eye Society and TFOS DEWS II, and it is necessary to develop a specific questionnaire that can be used to evaluate the severity of the DED and QOL in Japan.
The DEQS was developed as a dry eye–specific questionnaire to respond to the increasing need for a reliable assessment of the symptoms for diagnosing and evaluating the therapeutic effect of different agents for DED in Japan.
28 The DEQS was developed by referring to the U.S. Food and Drug Administration (FDA) guidelines for patient-reported outcome measures.
60 A validation study was conducted to verify the psychometric validity and reliability of this questionnaire. The DEQS consists of 15 items and two subscales: impact on daily life and bothersome ocular symptoms. In the validation study, the DEQS scores were compared to the Japanese version of VFQ-25 and the SF-8.
25,29 The score of each component, especially the mental component summary of the SF-8, was significantly correlated with the DEQS. When compared with the VFQ-25 “ocular pain,” which is only a subscale of the VFQ-25 and is apparently related to the typical symptoms of DED, it was strongly correlated with the summary score and each subscale score of the DEQS. A subscale of the DEQS that represents the impact on daily life was also strongly correlated with the three subscales: near vision, distance vision, and mental health. The DEQS can be easily applied in routine clinical practice and be completed in 5 minutes. It can evaluate the multifaceted impact of DED on the patient's daily life. However, the DEQS is not a suitable questionnaire to diagnose or to assess the degree of severity of the DED, although it is a useful tool for evaluating the effect of DED on the QOL or to evaluate the treatment effects on DED.
As listed in the
Table, there are different questionnaires in use to diagnose the DED, to assess the degree of severity, or to use for epidemiologic purposes. It is necessary to develop a new Japanese questionnaire for the different purposes, especially for diagnosing.