12.3Diagnostic Screening Examination

Examination of the eyes may reveal obvious injection, or the eyes may appear white and quiet. There is often some injection of the lid margins, in the absence of other evidence suggesting blepharitis such as collarettes about the lashes or scaling and crusting typical of staphylococcal and/or seborrheic involvement.

In more severe cases, the eyes actually look dry. The normal corneal luster is absent and no tear meniscus can be appreciated at the lid margin.

Examination with magniÞcation, performed in the ophthalmology ofÞce with a slit lamp, will commonly reveal diminished or absent tear meniscus at the lid margin and variable disruption and irregularity of the ocular surface.

Diagnostic dyes can be placed in the eye to demonstrate abnormal and/or absent epithelium on the cornea and conjunctiva:

Fluorescein is an orange dye used, along with a cobalt-blue light, to detect foreign bodies in the eye or damage to the cornea. It is most commonly used either instilled as a drop or from a commercially available strip of paper impregnated with the dye. This paper strip is wetted and touched to the lid margin. Areas of absent epithelium on the cornea stain and may be seen

as yellow-green areas of persistent dye, even after blinking.

¥Staining areas are more obvious ßuorescing under a cobalt-blue Þltered light, an option built into most slit lamps.

¥Mild-to-moderate cases exhibit punctate staining, while more severe cases may show conßuent areas of abnormal and absent epithelium.

¥These affected areas are characteristically located in the more exposed inferior portion of the cornea and the interpalpebral zones of the conjunctiva.

Rose Bengal is another dye used in the eye to reveal stained abnormal tissue and devitalized cells of the cornea in keratoconjunctivitis sicca. It can be instilled either in drop form or from an impregnated paper strip. It is more sensitive than ßuorescein, staining abnormal epithelial cells (as opposed to absent, dead epithelium). In the case of dry eyes, it can be particularly obvious on the conjunctiva and/or cornea in the most exposed inferior and interpalpebral areas.

¥Although the Rose Bengal is best done with a slit lamp by an ophthalmologist, it can also be performed by a rheumatologist using a simple ophthalmoscope (Fig. 12.1).

¥Increased uptake in the exposure zone (between the eyelids) can be visualized by retained dye, after the initial Rose Bengal is removed by application of artiÞcial tears.

¥The extent of staining may provide clues to help determine if the patientÕs symptoms of dry eyes are commensurate with the objective Þndings on examination.

When the rheumatologist does Rose Bengal

staining, topical anesthetic is not used. Lissamine Green is used to detect damaged

cells on the eyeÕs surface, ßagging them green under special lighting. It is an alternative to Rose Bengal that causes less stinging and less staining of the lid and facial skin if it overßows, thus, is more accommodating to the patient and the practitioner (and practitionerÕs white coat) alike. It must be stressed that positive staining with any of these dyes is seen in dry eye conditions but is not pathognomonic.

¥Any disorder, infection, noxious exposure, or insult to the ocular surface can produce similar patterns of abnormal or denuded epithelium and staining.

For those unfamiliar with the use of these dyes, it is advised to avoid ßooding the eye or using any more than a minimum amount necessary to expose the complete surface after a blink. More dye can obscure subtle areas of actual stain and produce unßattering messiness.

Ensure that a paper drape is provided to the patient for protection of garments prior to these potentially messy examination screenings.

Tear film breakup time is another common testÑactually observationÑwith ßuorescein dye. In this test, the time is measured with the eye kept open after the instillation of dye and a blink until its dissipation into a characteristic breakup into darker dry areas within the otherwise uniform tear/dye Þlm.

¥This test can be quite variable and insensitive, but if the amount of dye placed in the eye and extent of exposure are controlled, a positive test can be a strong indication of dysfunctional tear disorder.

¥The integrity of the outermost lipid layer of the three-part tear Þlm, moderating evaporation of the underlying aqueous component, is necessary to prevent abnormal breakup, but the test is usually positive in non-speciÞc

dysfunctional tear syndrome and SjšgrenÕs syndrome as well.

¥It is most useful in less obvious cases, particularly in disorders of the meibomian glands (the lipid producers).

Two observations well known to ophthalmologists, relating to the tear Þlm breakup, are worthy of mention.

1.A tear Þlm breakup time shorter than the time interval between normal blinks for a given patient will result in symptoms.

In fact, if a patientÕs eyes are kept open for more than a second after the tear Þlm breakup, more than 70% of patients will report ocular awareness.

2.For the clinician questioning a diagnosis of dry eye, a supportive observation is simply having the patient stare and report the time at which ocular awareness or irritation develops.

If the time from opening the lids to this sensation is less than 5 s, it is highly suggestive of an abnormal tear Þlm. Normal response is greater than 5 s, with a mean of about 7 s.

In the standard observation for breakup utilizing a slit lamp with copious ßuorescein in the tear Þlm, 10 s or more is considered a normal breakup time.

Under more standardized and critical tech-

niques applying only 5 μL of ßuorescein, a positive test is considered less than 5 s.

The Schirmer’s test is probably the most common diagnostic test used by ophthalmologist and non-ophthalmologist alike to diagnose dry eye syndrome. It is used to determine whether the eye produces enough tears to keep it adequately moist.

In this test, a small strip of Þlter paper is placed over the lid margin, usually at the junction of the mid and lateral thirds, and the amount of wetting observed after 5 min.

There is no unanimous agreement on the best way to perform this test; however, it can be done with or without topical anesthesia, yielding different results depending upon the patient and conditions.

Obviously, with adequate topical anesthesia, one attempts to eliminate the foreign body