In 1903, Schirmer described this technique for evaluation of tear production. Since that time the Schirmer tests have become an important clinical tool for the diagnosis of dry eye and hypersecretion syndromes. The Schirmer I test is used to evaluate gross tear production. It is usually performed without topical anesthetic. A strip of #41 Whatman filter paper, 50 mm long and 5 mm wide, is folded 5 mm from one end, and the small folded end is placed into the inferior conjunctival fornix at the junction of the lateral and middle thirds of the lower eyelid. The amount of wetting on the filter paper is measured at 5 min [14]. The test should be performed in subdued lighting, and both eyes must be tested simultaneously. This test measures the aqueous component of the tear film and does not distinguish between basic and reflex tear production. It gives only a very crude estimate of tear flow, since the paper itself may stimulate reflex lacrimation. It is important to blot any tears that are in the fornix prior to performing this test. If the investigator is not careful to wipe the tear lake from the conjunctiva prior to inserting the paper strips, an excessive degree of wetting will be recorded. If the tear drainage system is functioning, a significant volume of tear flow passes into the puncta without being recorded on the paper strip. The fractional volume lost is in proportion to the adequacy of the drainage system and may be significantly more than the volume recorded on the strip. Normal values for the Schirmer I test range from 10 to 30 mm of wetting at 5 min, with values over 25 mm typical of patients under age 30 and values of 10 mm or less in those over age 60. It is important to remember that any specific measurement, say 15 mm of wetting, will have very different meanings in patients with a normal drainage system compared to those with some degree of obstruction.

If the Schirmer I test is abnormal, the test may be modified to separate the reflex component from basic secretion. A drop of topical anesthetic is instilled into the eye and the test is repeated. This test should be performed in subdued lighting, as light can stimulate reflex tearing from the lacrimal gland. Any combination of basic and reflex tearing may be found in patients with symptomatic dry eye or epiphora, and the volume of aqueous flow alone is not a complete indication of lacrimal system function.

When the Schirmer I test is below normal, the Schirmer II test will give some indication of stressed reflex capability. Topical anesthetic is used in the eye, and the nasal mucosa is stimulated mechanically with a cotton swab or chemically with ammonium chloride. The amount by which the Schirmer II test exceeds basic production represents stressed reflex secretion.

The 5-min testing interval used in the standard Schirmer test can cause discomfort to some patients and may cause hypersecretion that can produce a falsely high test result. Karampatakis et al. [15] showed that a 2-min test gave acceptable results that correlated well with the 5-min results in 94.5 % of cases, where most normal individuals show wetting equal to or greater than 10 mm.

Rose Bengal is a chloride-substituted iodinated fluorescein dye that stains devitalized epithelial cells. Increased conjunctival staining is a sensitive indicator of inadequate tear function, regardless of gross aqueous tear flow determined by the Schirmer test. In such cases, essential layers such as surfactant and lipids can make the tear film inadequate to protect the cornea. In the patient with epiphora and significant staining, reflex hypersecretion and inadequacy of tear physiology should be suspected.

Stability of the normal tear film depends upon its basal mucin layer, which increases the hydrophilic quality of epithelial cells, allowing uniform wetting of the corneal surface. When this mucin component is reduced, the tear film will break up on the relatively more hydrophobic corneal surface. The tear breakup time is a simple clinical test for evaluation of this component of tear function. One drop of fluorescein is placed in the eye and the patient is instructed to blink once. Observing the corneal surface under slit-lamp magnification with cobalt blue illumination, the observer notes the time it takes in seconds for dry spots appear in the tear film. Normal tear breakup time is between 15 and 30 s. A tear breakup time of less than 10 s indicates a probable mucin deficiency, which may result not only in the symptoms of dry eye syndrome, but also in reflex hypersecretion of the aqueous tear component and in epiphora.

The dye disappearance test is usually performed as part of the primary Jones dye test (Jones I test). It is a rudimentary measurement of the rate of tear flow out of the conjunctival sac. One drop of 2 % fluorescein is placed in the lower conjunctival fornix and the amount remaining at 5 min is graded on a 0 to 4+ scale, with 0 representing no dye remaining and 4+ representing all the dye remaining. The test is most meaningful when both sides are compared simultaneously. Little or no fluorescein remaining in the conjunctival sac (a positive test) indicates probable normal drainage outflow, whereas most or all of the dye remaining (negative test) indicates partial or complete obstruction, or pump failure. Care must be taken to note any overflow of tears onto the cheek, and the patient is instructed not to blot the eyes with tissue during the test. In addition, a significant amount of dye may disappear in the presence of a large dilated sac mucocele even with a more distal obstruction. The test cannot distinguish between physiologic and anatomic causes of drainage dysfunction, nor can it localize the site of any mechanical blockage. It only indicates whether tear flow out of the fornix is normal or delayed. The dye disappearance test has been shown to be positive (normal outflow) in 95 % of asymptomatic normal individuals and may be more sensitive than the primary Jones test [16]. Unlike the latter, it does not appear to be dependent upon gross tear flow as measured by the Schirmer test.

In 1961, Jones described a simple test of lacrimal drainage function that has become one of the most used procedures in the evaluation of epiphora. The primary Jones dye test (Jones I) is a true functional test and should be carried out in as nearly physiologic conditions as possible. The patient should be in an upright position, and should blink normally. Topical anesthesia is not used, although the clinician may anesthetize the nasal mucosa for comfort. Two percent fluorescein solution is instilled into the conjunctival sac and a fine cotton-tipped applicator is passed beneath the inferior turbinate to the level of the nasolacrimal ostium after 2 min and again after 5 min. Alternatively, the patient is asked to blow their nose onto a clean tissue. The test is positive if dye is recovered in the nose, and indicates patent anatomy and adequate physiological function. However, the dye may be very difficult to retrieve and therefore there is a high false negative rate with this test. Transit time for the dye to reach the nose is quite variable and shows a significant correlation with the Schirmer test. Even in eyes without epiphora, passage of dye into the nose may take considerably longer than the 5 min allowed for the test. A 10 min interval will result in a greater number of positive tests. Also, testing conditions may alter results since transit time is influenced by factors such as blink rate, head position and gravity, and fluorescein volume. Experience in placing the dye (drops vs. strips) and techniques for obtaining dye from the nose may also influence the recovery rate. Although a positive test strongly suggests a normal system, it does not completely rule out physiological dysfunction or mild anatomic obstruction. More significantly, a negative test alone does not necessarily indicate abnormal drainage, and even in asymptomatic normal patients the overall positive recover rate is typically only in the range of 85 % [17].

The fluorescein appearance test, described by Flach, is a modification of the primary Jones dye test [18]. It is designed to avoid the difficulty and variability involved in recovering dye from the inferior nasal meatus. Two percent fluorescein is placed in the conjunctival sac and the oropharynx is examined with ultraviolet light, beginning at 5 min and continuing up to 1 h if necessary. With this technique 90 % of normal individuals are said to show oropharyngeal fluorescence within 30 min, and 100 % within 60 min. This procedure is best used as a supplement to a negative primary Jones test and can be performed 20–30 min later. Because of the persistence of fluorescence, only one eye can be tested by this technique during a single office visit.

In 1973, Hornblass [19] elaborated on a variation of the primary Jones dye test originally mentioned by Lipsius [20]. In this version, 0.4 mL of 1 % sterile solution of sodium saccharin is instilled into the conjunctival sac and the patient is asked to report when he or she tastes the solution. Hornblass found a mean transit time to the nose of 3.5 min, with 65 % of normal individuals reporting a positive test within 6 min, and 90 % reporting positive results within 15 min. Transit times in excess of 15 min suggest partial nasolacrimal duct obstruction. The test depends on a subjective response from the patient, and before the solution can be tasted it must pass into the pharynx, where threshold taste sensitivity is quite variable. Lipsius noted that 3 % of normal individuals were incapable of tasting saccharin.

A negative primary Jones dye test suggests delayed transit time through the lacrimal drainage system but it does not differentiate physiologic dysfunction from anatomic obstruction. The secondary Jones dye test (Jones II) evaluates anatomic patency of the system in such cases. Residual fluorescein left from the primary test is flushed from the conjunctival sac and a topical anesthetic is instilled. The patient sits with head tilted slightly forward while clear saline is irrigated into one canaliculus through a cannula (Fig. 7.3). The patient is instructed to blow or spit any fluid that passes into the nose or pharynx onto a clean tissue. The passage of any fluid into the nose indicates gross anatomic patency of the nasolacrimal system. In this situation, complete obstruction is not present since saline did traverse the system under pressure. Dye in the fluid demonstrates normal punctal and canalicular anatomy, since the dye must have passed freely into the sac during the previous Jones I test. However, such a result does not rule out a partial anatomic block at the level of the lower sac or duct. Recovery of clear saline in the nose without fluorescein suggests punctal or canalicular stenosis or pump failure, where dye from the primary Jones test did not enter the lacrimal sac. If fluid does not reach the nose at all, but regurgitates from the puncta, a high-grade NLD obstruction is likely that cannot be overcome with increased hydrostatic pressure. Punctal regurgitation of dye-stained fluid suggests blockage at the level of the lower sac or duct, with residual dye in the sac being flushed out by the irrigation. Very rarely, a dilated canalicular mucocele may retain sufficient dye to produce similar results. Regurgitation of clear saline from the opposite punctum suggests obstruction at the level of the distal common canaliculus or upper sac with no residual dye from the primary Jones test. When clear saline regurgitates from the same punctum that is being irrigated without flow from the opposite punctum, a proximal obstruction in that canaliculus is likely.

During the irrigation of saline, distension of the lacrimal sac to palpation may sometimes be seen and is suggestive of lower nasolacrimal duct obstruction. Under such conditions a palpable sac without fluid passing into the nose suggests complete nasolacrimal duct blockage, whereas a palpable sac with fluid passing into the nose implies a partial obstruction. A sac that is contracted and fibrotic because of chronic inflammation will not dilate under these conditions.

The secondary Jones dye test evaluates anatomic patency under increased hydrostatic pressure. When positive, it does not differentiate between epiphora caused by physiological dysfunction and epiphora resulting from partial anatomic obstruction. When a primary Jones test is positive (dye recovered in the nose), the secondary Jones test should always be positive and is therefore unnecessary. With a negative primary test, a positive secondary test would be consistent with physiologic or partial anatomic dysfunction. Negative results (no dye recovered) on both the primary and secondary tests confirm a high-grade obstruction.

False-positive results are not uncommon when a diagnosis of NLD obstruction is based on the irrigation test alone. Beigi et al. [21] noted a high rate of false tests where re-examination showed canalicular stenosis, punctal abnormalities, or hypersecretion.

Dacryomeniscometry has been used in the past to evaluate dry eyes. More recently, it has been applied to evaluation of tear meniscus height in patients with epiphora from primary acquired nasolacrimal duct obstruction and from functional nasolacrimal drainage system failure [22]. The tear meniscus in patients with functional or anatomic NLD obstructions is significantly higher than in normal controls [23], and reduces to near normal after corrective DCR surgery. The technique may be useful to identify individuals with drainage dysfunction from a variety of etiologies, but must be combined with other tests in order to diagnose the specific etiology.

When the secondary Jones test indicates canalicular obstruction, the canaliculus in question should be probed gently to the lacrimal sac with a small Bowman probe (Fig. 7.4). The punctum may first be dilated by pulling the lid laterally to prevent canalicular kinking and inserting a pointed dilator. The distance of the stenosis or blockage from the punctum is noted in millimeters by measuring directly on the probe. In most individuals, a short common canaliculus is present 6–9 mm from the puncta. The canalicular system should not be probed without prior indication of possible obstruction because of the risk of inadvertent injury and subsequent fibrosis.