Diagnosis of Keratoconjunctivitis Sicca
The above definition of the dry eye accentuates the following features of the disease: (1) symptoms; (2) interpalpebral surface damage; (3) tear instabil¬ity, and (4) tear hyperosmolarity. There are numerous tests for the diagnosis of dry eye and they vary with respect to their invasiveness. The selection and order of these tests is of paramount importance since each test may influence the out¬come of the test which follows. In general it is recommended to start with the least invasive procedure and to end with the most invasive test. Occasionally it is necessary to perform some tests on a subsequent day. At the end of a battery of tests it should be possible to confirm the diagnosis, classify the form of dry eye, being conscious of its grade, and initiate appropriate therapy.
Symptoms and History
A record of clinical history and ocular symptoms is required. Several ques-tionnaires have been developed for the assessment of dry eye . A special questionnaire for the detection of psychosomatic alterations exists and can be applied additionally .
Important aspects of the patient's history are: (a) symptoms: burning sen-sation, foreign body sensation, tired eye, photophobia, epiphora, swelling of the lids; (b) onset of the symptoms, duration; (c) circadian rhythm; (d) environmen¬tal conditions at home and in the office (smoke, wind, humidity); (e) contact lens-associated problems; (f) cosmetics; (g) systemic diseases; (h) allergic dis¬eases; (i) dermatologic diseases, and (j) drug history.
Examination of the Lids
The dynamics of blinking and of lid position should be observed whilst taking the history in order to prevent conscious alterations. Points of interest are: (a) frequency of blinking; (b) variation of blink intervals; (c) size of the palpebral aperture, and (d) adequacy of lid closure.
The position of the lids may influence the tear turnover, therefore care should be taken to identify the following malpositions: (a) entropion; (b) ectro- pion; (c) eversion of the lacrimal puncta; (d) cicatrical malposition; (e) derma- tochalasis, and (f) swelling of the temporal aspect of the upper lid, implying enlargement of the lacrimal gland.
Slit-Lamp Examination
Slit-lamp biomicroscopy should evaluate the following anatomical structures and their alterations: (a) Lid margins: hyperaemia, telangiectasia, thickening, scar-ring, keratinization, ulceration, tear debris, abnormalities of the meibomian
orifices, metaplasia, character of expressed meibomian secretions. (b) Eyelashes: misdirection, malposition, encrustations, collarettes. (c) Conjunctiva: erythema, swelling, keratinization, papillary/follicular reaction, pinguecula, lid parallel con-junctival folds. (d) Cornea: infiltrates, scars, punctuate staining or ulcers, vascu-larization, pannus, and pterygium. (e) Additionally, the tear film should be analysed for: filaments, mucus, and cellular debris, meibomian foam.
Non-Invasive Break-Up Time
The non-invasive break-up time test was created to measure the stability of the precorneal tear film without any dye . It involves projection of a target onto the convex mirror surface of the tear film and recording the time taken for the image to break up after a blink. The test was originally performed with a custom-built 'Toposcope' but has also been performed over a limited zone of the exposed precorneal film, using a keratometer. It can also be measured with the TearscopePlus™ and is a non-invasive procedure .
Interferometry
Tear film interferometry is a non-invasive technique for grading the behav¬iour of the tear film lipid layer and estimating its thickness on the basis of the observed interference colours (fig. 4). It is useful for selecting dry eye
candidates for punctal occlusion. Apparatus which have been used for this pur¬pose include the TearscopePlus and the Kowa DR-1.
A colour scale which has been used is as follows : (a) greyish colours, uniform: normal; (b) greyish colours, non-uniform: normal; (c) yellow colours: dry eye; (d) brown colours: dry eye, and (e) blue colours: dry eye.
The above definition of the dry eye accentuates the following features of the disease: (1) symptoms; (2) interpalpebral surface damage; (3) tear instabil¬ity, and (4) tear hyperosmolarity. There are numerous tests for the diagnosis of dry eye and they vary with respect to their invasiveness. The selection and order of these tests is of paramount importance since each test may influence the out¬come of the test which follows. In general it is recommended to start with the least invasive procedure and to end with the most invasive test. Occasionally it is necessary to perform some tests on a subsequent day. At the end of a battery of tests it should be possible to confirm the diagnosis, classify the form of dry eye, being conscious of its grade, and initiate appropriate therapy.
Symptoms and History
A record of clinical history and ocular symptoms is required. Several ques-tionnaires have been developed for the assessment of dry eye . A special questionnaire for the detection of psychosomatic alterations exists and can be applied additionally .
Important aspects of the patient's history are: (a) symptoms: burning sen-sation, foreign body sensation, tired eye, photophobia, epiphora, swelling of the lids; (b) onset of the symptoms, duration; (c) circadian rhythm; (d) environmen¬tal conditions at home and in the office (smoke, wind, humidity); (e) contact lens-associated problems; (f) cosmetics; (g) systemic diseases; (h) allergic dis¬eases; (i) dermatologic diseases, and (j) drug history.
Examination of the Lids
The dynamics of blinking and of lid position should be observed whilst taking the history in order to prevent conscious alterations. Points of interest are: (a) frequency of blinking; (b) variation of blink intervals; (c) size of the palpebral aperture, and (d) adequacy of lid closure.
The position of the lids may influence the tear turnover, therefore care should be taken to identify the following malpositions: (a) entropion; (b) ectro- pion; (c) eversion of the lacrimal puncta; (d) cicatrical malposition; (e) derma- tochalasis, and (f) swelling of the temporal aspect of the upper lid, implying enlargement of the lacrimal gland.
Slit-Lamp Examination
Slit-lamp biomicroscopy should evaluate the following anatomical structures and their alterations: (a) Lid margins: hyperaemia, telangiectasia, thickening, scar-ring, keratinization, ulceration, tear debris, abnormalities of the meibomian
orifices, metaplasia, character of expressed meibomian secretions. (b) Eyelashes: misdirection, malposition, encrustations, collarettes. (c) Conjunctiva: erythema, swelling, keratinization, papillary/follicular reaction, pinguecula, lid parallel con-junctival folds. (d) Cornea: infiltrates, scars, punctuate staining or ulcers, vascu-larization, pannus, and pterygium. (e) Additionally, the tear film should be analysed for: filaments, mucus, and cellular debris, meibomian foam.
Non-Invasive Break-Up Time
The non-invasive break-up time test was created to measure the stability of the precorneal tear film without any dye . It involves projection of a target onto the convex mirror surface of the tear film and recording the time taken for the image to break up after a blink. The test was originally performed with a custom-built 'Toposcope' but has also been performed over a limited zone of the exposed precorneal film, using a keratometer. It can also be measured with the TearscopePlus™ and is a non-invasive procedure .
Interferometry
Tear film interferometry is a non-invasive technique for grading the behav¬iour of the tear film lipid layer and estimating its thickness on the basis of the observed interference colours (fig. 4). It is useful for selecting dry eye
candidates for punctal occlusion. Apparatus which have been used for this pur¬pose include the TearscopePlus and the Kowa DR-1.
A colour scale which has been used is as follows : (a) greyish colours, uniform: normal; (b) greyish colours, non-uniform: normal; (c) yellow colours: dry eye; (d) brown colours: dry eye, and (e) blue colours: dry eye.
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