General Information and Recommendations
Diagnostic tests of dry eye states are in general intended for two groups of patients: those who come for the first visit with a suspected dry eye and those who have already undergone therapy elsewhere and wish further advice. In the
first group of patients the test series for dry eye can be started immediately. In the second group of patients it is recommended to stop the patients' preexisting therapy for 1 week and start the testing after wards. This opens the pathway towards an exact diagnosis without any therapeutic interference.
For the routine diagnostic way of a suspected dry eye state it is advised to select a number of tests. Non-invasive procedures like questionnaires, symptoms and history and slit-lamp examination are among these and often are called low-tech diagnostic. Considering patients' comfort and economic aspects, simple tests should always be used. These tests provide already a reliable information of the dry eye condition. A questionnaire has a surprisingly high sensitivity of 77% with a specificity of 81% . In combination with data from other non-invasive methods, sensitivity and specificity can even be raised. Slit-lamp characteristics like an irregularity of the black line or hyper- aemia of the conjunctiva result in a sensitivity of 92% and a specificity of 81% . Simple low-tech diagnostic is therefore the basis of the dry eye testing.
Besides that, a battery of dry eye tests exist which are mildly or markedly nvasive. The order of tests is of critical importance since one test may influence the result of the next. Therefore it is recommended to start with the least invasive test and to end with the most invasive procedure. Some tests are mutually exclusive, which means that in a certain patient only a selection of dry eye tests is performed.
Within this system of tests (table 2) with increasing invasiveness, intervals of 5 min are recommended between invasive tests. This is the time necessary for restoration of the original meniscus height . For the routine dry eye patient a sequence of tests giving the essential information for the classification should be selected .
After having selected the appropriate combination of tests, the grading and interpretation of these tests gains importance. It is essential to know the informa¬tion we can get from a certain test in order to classify our patient's dry eye form as tear-deficient or evaporative. If you suspect a hyperevaporative dry eye the non-invasive BUT and meibography should be measured. Meniscometry and Schirmer I test are specifically indicative for the hypovolemic dry eye. The same tests give us sufficient information about the severity of the ocular surface disease. Staining with Lissamine and fluorescein allow a more precise quantification of the severity and are therefore recommended . The interpretation is based on agrading system of the tests mentioned above. This system allows us to distinguish normal from marginal dry eyes or manifest dry eye patients.
Once the diagnosis is confirmed and the grade of the disease established the patients need follow-up examinations. The course of the KCS under therapy is documented. We get the best information from a repetition of the tests which have been selected initially. This pathway of examination provides reliable information about the course of the disease and forms the basis for longitudinal observations. However, we have to take into account that certain tests like fluorescein and rose bengal staining show limits with respect to their reliability at different times. Nevertheless, these tests are necessary to provide exact information about the localization of ocular surface defects, whereas the non-invasive tests give us broader information about the whole ocular surface. The diagnosis of dry eye is therefore based on the data of different tests with increasing invasiveness arranged in a way to minimize interference between the tests and on the grading of the results which permit a selection of the appropriate therapy and a long-term obser¬vation of the patient.
Diagnostic tests of dry eye states are in general intended for two groups of patients: those who come for the first visit with a suspected dry eye and those who have already undergone therapy elsewhere and wish further advice. In the
first group of patients the test series for dry eye can be started immediately. In the second group of patients it is recommended to stop the patients' preexisting therapy for 1 week and start the testing after wards. This opens the pathway towards an exact diagnosis without any therapeutic interference.
For the routine diagnostic way of a suspected dry eye state it is advised to select a number of tests. Non-invasive procedures like questionnaires, symptoms and history and slit-lamp examination are among these and often are called low-tech diagnostic. Considering patients' comfort and economic aspects, simple tests should always be used. These tests provide already a reliable information of the dry eye condition. A questionnaire has a surprisingly high sensitivity of 77% with a specificity of 81% . In combination with data from other non-invasive methods, sensitivity and specificity can even be raised. Slit-lamp characteristics like an irregularity of the black line or hyper- aemia of the conjunctiva result in a sensitivity of 92% and a specificity of 81% . Simple low-tech diagnostic is therefore the basis of the dry eye testing.
Besides that, a battery of dry eye tests exist which are mildly or markedly nvasive. The order of tests is of critical importance since one test may influence the result of the next. Therefore it is recommended to start with the least invasive test and to end with the most invasive procedure. Some tests are mutually exclusive, which means that in a certain patient only a selection of dry eye tests is performed.
Within this system of tests (table 2) with increasing invasiveness, intervals of 5 min are recommended between invasive tests. This is the time necessary for restoration of the original meniscus height . For the routine dry eye patient a sequence of tests giving the essential information for the classification should be selected .
After having selected the appropriate combination of tests, the grading and interpretation of these tests gains importance. It is essential to know the informa¬tion we can get from a certain test in order to classify our patient's dry eye form as tear-deficient or evaporative. If you suspect a hyperevaporative dry eye the non-invasive BUT and meibography should be measured. Meniscometry and Schirmer I test are specifically indicative for the hypovolemic dry eye. The same tests give us sufficient information about the severity of the ocular surface disease. Staining with Lissamine and fluorescein allow a more precise quantification of the severity and are therefore recommended . The interpretation is based on agrading system of the tests mentioned above. This system allows us to distinguish normal from marginal dry eyes or manifest dry eye patients.
Once the diagnosis is confirmed and the grade of the disease established the patients need follow-up examinations. The course of the KCS under therapy is documented. We get the best information from a repetition of the tests which have been selected initially. This pathway of examination provides reliable information about the course of the disease and forms the basis for longitudinal observations. However, we have to take into account that certain tests like fluorescein and rose bengal staining show limits with respect to their reliability at different times. Nevertheless, these tests are necessary to provide exact information about the localization of ocular surface defects, whereas the non-invasive tests give us broader information about the whole ocular surface. The diagnosis of dry eye is therefore based on the data of different tests with increasing invasiveness arranged in a way to minimize interference between the tests and on the grading of the results which permit a selection of the appropriate therapy and a long-term obser¬vation of the patient.
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