Lacrimal outflow examination
Examination of a patient with abnormal lacrimal outflow begins with an observation of the eyelid and puncta positions during the blink cycle. Facial nerve dysfunction can result in a weakened blink and poor lacrimal pump function (Fig 15-11). An enlarged caruncle or conjunctivochalasis (Fig 15-12) can also mechanically block the aperture of the puncta and lead to tearing. Punctal stenosis, occlusion, or aplasia may be present.
Palpation of the lacrimal sac may cause reflux of mucoid or mucopurulent material through the canalicular system, confirming complete NLDO. No further diagnostic tests are needed if a lacrimal sac tumor is not suspected.
Nasal examination may uncover an unsuspected cause of the epiphora, such as an intranasal tumor or polyp, turbinate impaction, deviated septum, or chronic allergic rhinitis. These conditions may occlude the nasal end of the NLD.
Diagnostic tests
As originally outlined by Lester Jones, the clinical evaluation of the lacrimal drainage system historically comprised a dye disappearance test (DDT) followed by the Jones I test (swabbing the inferior meatus to see if dye passes through physiologically) and the Jones II test (irrigating with saline and assessing the passage of fluid and presence or absence of dye). Although some clinicians continue to rely on formal Jones testing, most use a simplified approach involving only the DDT and lacrimal irrigation.
The DDT is useful for assessing the presence or absence of adequate lacrimal outflow, especially in unilateral cases. It is more heavily relied upon for children, in whom lacrimal irrigation is impossible without deep sedation. Fluorescein is instilled in both eyes, and the tear film is observed with the cobalt blue filter of a slit lamp or direct ophthalmoscope. Persistence of significant dye over a 5-minute period implies decreased outflow. Asymmetry in dye clearance during the DDT can be a particularly helpful diagnostic clue (Fig 15-13). If the DDT result is normal, severe lacrimal drainage dysfunction is unlikely. However, intermittent causes of tearing, such as an allergy, dacryolith, or intranasal obstruction, cannot be ruled out.
Lacrimal drainage system irrigation is most frequently performed immediately after the DDT to determine the level of lacrimal drainage system occlusion (Video 15-1). After instillation of topical anesthesia, the lower eyelid punctum is dilated, and any punctal stenosis is noted. The irrigating cannula is placed in the canalicular system. To prevent canalicular kinking and difficulty in advancing the irrigating cannula, the clinician maintains lateral traction of the lower eyelid (see Fig 15-6). Canalicular stenosis or occlusion should be recorded and confirmed by subsequent diagnostic probing. Once the irrigating cannula has been advanced into the horizontal canaliculus, clear saline is injected and the results are noted. Careful observation and interpretation determine the area of obstruction without additional testing.
VIDEO 15-1 Lacrimal dilation and irrigation.
Courtesy of Eric A. Steele, MD. Access all Section 7 videos at
www.aao.org/bcscvideo_section07.
Difficulty advancing the irrigating cannula and an inability to irrigate fluid suggest total canalicular obstruction. If saline can be irrigated successfully but it refluxes through the upper canalicular system and no distention of the lacrimal sac is observed on palpation, complete blockage of the common canaliculus is probable (Figs 15-14, 15-15). Subsequent probing determines whether the common canalicular stenosis is total or whether it can be dilated. If mucoid material or saline refluxes through the opposite punctum and lacrimal sac distention is palpable, the diagnosis is complete NLDO (Video 15-2). If saline irrigation is not associated with canalicular reflux or fluid passing down the NLD, the lacrimal sac will become distended, causing patient discomfort. This result confirms a complete NLDO with a functional valve of Rosenmüller, preventing reflux through the canalicular system. A combination of simultaneous saline reflux through the opposite canaliculus and saline irrigation through the NLD into the nose may indicate a partial NLD stenosis.
VIDEO 15-2 Lacrimal irrigation showing a complete nasolacrimal duct obstruction.
Courtesy of Bobby S. Korn, MD, PhD.
If saline irrigation passes freely into the nose with no reflux through the canalicular system, an anatomically patent nasolacrimal drainage system is present. However, it is important to note that even though this irrigation is successful under increased hydrostatic pressure from the irrigating saline, a functional obstruction may still be present. A dacryolith may also impair tear flow without blocking irrigation.
Diagnostic probing of the upper system (puncta, canaliculi, and lacrimal sac) is useful in confirming the level of obstruction. In adults, this procedure can easily be performed with topical anesthesia. A small probe is used initially to detect any canalicular obstruction. If an obstruction is encountered, the probe is clamped at the punctum before withdrawal, thereby measuring the distance to the obstruction. A larger probe may be useful to determine the extent of a partial obstruction, but the probe should not be forced through any area of resistance.
Diagnostic probing of the NLD is not used in adults because there are other means of diagnosing NLDO. In addition, probing in adults has limited therapeutic value, rarely producing lasting patency. In contrast, probing in infants is a useful and largely successful procedure. This reflects the differing pathophysiologies of congenital NLDO and acquired NLDO: The former often results from occlusion of the NLD by a thin membrane and the latter from more extensive fibrosis of the duct itself.
Intranasal examination is performed with a nasal speculum and light source. Diagnostic nasal endoscopy can be helpful in the evaluation of the nasal anatomy and in the identification of disease processes.
Contrast dacryocystography and dacryoscintigraphy are alternative methods of evaluation. Contrast dacryocystography, which involves injection of dye into the lacrimal system followed by computerized digital subtraction imaging, provides anatomical information of any obstructed sites. In dacryoscintigraphy, a physiologic picture of lacrimal outflow is obtained by using radionucleotide eyedrops to follow tear flow on a scintigram.
CT and MRI are useful in the evaluation of craniofacial injury, congenital craniofacial deformities, or suspected neoplasia. CT is superior for the evaluation of suspected bony abnormalities, such as fractures. MRI is superior for the evaluation of suspected soft-tissue disease, such as malignancy. Either CT or MRI may be helpful in evaluating concomitant sinus or nasal disease that may contribute to excess tearing.
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Kashkouli MB, Mirzajani H, Jamshidian-Tehrani M, Pakdel F, Nojomi M, Aghaei GH. Reliability of fluorescein dye disappearance test in assessment of adults with nasolacrimal duct obstruction. Ophthalmic Plast Reconstr Surg. 2013;29(3):167–169.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.