Continuing Education Activity

A watery eye is a common complaint among patients visiting the eye doctor. This condition affects all age groups due to different etiologies. It can negatively impact patients' lives and be a manifestation of systemic disease. Due to its multifactorial nature, a comprehensive history and workup are essential to detect the possible causes of the watery eye. Failure to do that can result in unsuccessful treatment. This activity reviews the assessment and management of the watery eye. It also highlights the role of the healthcare team in managing patients with this condition.

Objectives:

• Review the etiology and pathophysiology of watery eyes.
• Summarize the epidemiology of watery eyes.
• Explain the physical exam findings of watery eyes.
• Describe the treatment of watery eyes.

Introduction

The tear film is essential in lubricating and protecting the ocular surface and contributing to vision quality.[1] However, excess tearing is likely to affect patients´ lives negatively, which results in a common complaint encountered in ophthalmology clinics.

This excess tearing may be caused by problems with increased tear production, poor distribution due to lacrimal pump failure, decreased drainage, or a combination of these factors.[2] Therefore, a thorough history and examination are required to evaluate all the possible factors causing a watery eye and to provide adequate treatment tailored to the underlying specific cause or combination of etiologies.[3]

Etiology

A watery eye is a complex symptom to tackle, as the following etiologies may be implicated:

Conditions Affecting the Eyelids and Peri-ocular Region

• Skin conditions (such as rosacea, eczema, actinic keratoses, ichthyosis, zoster, scleroderma, lichen planus, or discoid lupus) cause tearing due to stimulating reflex tearing, impairing the tear distribution system or a combination of both.[4][5][6][7]
• Facial akinesia: In this condition, blink dynamics are altered, causing reflex tearing due to corneal exposure and negatively affecting the tear-pumping mechanism. 
• Brain disorders (such as Parkinson's disease and progressive supranuclear palsy): These conditions alter the blink neuronal circuit, which causes decreased blink rate and amplitude, resulting in pumping problems and reflex tearing triggered by desiccation of the ocular surface.
• Facial nerve palsy: The facial nerve innervates the orbicularis muscle, so conditions causing facial nerve palsy may result in abnormal lower eyelid position (paralytic ectropion), decreased upper eyelid excursion (causing ocular surface exposure and reflex tearing), and reduced orbicularis contraction affecting the pumping mechanism for tears egress.[6]
• Aberrant seventh nerve regeneration can result in tearing while eating or drinking ("crocodile tears") due to abnormal connections with the lacrimal ducts instead of the salivary glands.[8]
• Space-occupying lesions or drugs (such as cholinergic agents) stimulating parasympathetic lacrimal fibers result in an increased production of tears.
• Lacrimal gland tumors (such as dacryops) can cause primary tear hypersecretion.[9]
• Dacryoadenitis. Inflammation of the lacrimal gland as a result of infection (such as Epstein-Barr, Staphylococcus aureus, or tuberculosis), autoimmune (such as Sjogren disease, Thyroid eye disease, or Immunoglobulin G4-related disease), or idiopathic process (such as non-specific orbital inflammation, or sarcoidosis), can manifest with tearing.[10]
• Botulinum toxin, when applied in the peri-ocular area, can decrease orbicularis muscle function.
• Herniation of orbital fat: This causes a watery eye due to displacing the tear meniscus and altering tear flow along the eyelid margin.[6]
• Lumps in or around the eyelids may irritate the ocular surface causing reflex tearing. 
• Eyelid burns and scars may cause lid malposition and alteration of blink dynamics.
• Floppy eyelid syndrome causes tearing by a combination of reflex hypersecretion, deficient distribution of the tear film, and ineffective lacrimal pump.
• Eyelid retraction in exophthalmos (Graves ophthalmopathy): An incomplete blink due to the widened eyelid fissure disrupts proper corneal lubrication. Nocturnal lagophthalmos (incomplete eyelid closure) with an abnormal Bell's phenomenon due to fibrotic inferior recti causes exposure keratopathy and reflex tearing. In addition, associated conjunctival chemosis disrupts tear flow along the lower eyelid.
• Eyelid retraction due to surgery, trauma, or skin conditions may trigger reflex tearing. 
• Eyelid imbrication syndrome: The lax upper lid overrides the lower lid during closure. As a result, the disrupted distribution of the tear film on the ocular surface is combined with reflex tearing due to rubbing the tarsal conjunctiva on the surface. In addition, the punctum is in an abnormal position, which impedes tears outflow.
• Eyelid length disparity can result in abnormal eyelid closure and subsequent reflex tearing due to corneal exposure. 
• Lower lid laxity causes pump problems due to poor apposition of the eyelids against the eye. It affects the eyelid's position, which creates an abnormal gradient for the tear to flow toward the punctum with each blink.[6]
• Entropion from any cause: In entropion, the eyelashes are directed inward, rubbing the cornea or conjunctiva and causing reflex tearing. In addition, the punctum is in an unfavorable position to receive tears. This condition results from one or a combination of the following causes: horizontal eyelid laxity, posterior lamella scar, dehiscence of lower eyelid retractors, and overriding preseptal orbicularis. 
• Ectropion from any cause: The ectropic eyelid displaces the tear lake from the eyelid margin and stops tears from reaching the punctum. One or a combination of the following factors may cause this problem: lower eyelid retractor disinsertion, horizontal eyelid laxity, medial canthal tendon laxity, vertical tightness of the skin, orbicularis paresis, and puncta malposition. Clinical examination will help to determine the presence of each factor.[6]
• Eyelid notches and tumors alter the tear distribution over the eye surface.
• Keratinization of the eyelid margin: The contact between the keratinized margin and the anterior surface causes irritation and reflex tear hypersecretion: This is also called lid-wiper epitheliopathy.[11]
• Malpositioned eyelashes (trichiasis, distichiasis) rub the cornea or conjunctiva and cause reflex tearing.
• Blepharitis/meibomian gland dysfunction: Chronic blepharitis may cause posterior lamellar shortening resulting in lashes rubbing the eye surface and causing reflex tearing. In meibomian gland dysfunction, a decreased tear film lipid layer increases tear evaporation and may result in compensatory tear hypersecretion.  

Conditions Affecting the Ocular Surface

• A foreign body in the cornea or conjunctiva irritates the ocular surface and causes reflex tearing.
• Conjunctival inflammation causes reflex tearing by stimulating the neurosensory receptors.  
• Conjunctivochalasis. The redundant bulbar conjunctiva displaces the normal tear meniscus and impedes the flow toward the punctum.[6] Moreover, it may mechanically irritate the eye, which causes reflex tearing. 
• Conjunctival symblepharon can cause eyelid malposition, resulting in lagophthalmos and poor blinking. 
• Pinguecula and pterygia alter tear distribution over the eye surface.
• Dry eyes have a component of inflammation and tear instability that stimulate corneal and conjunctival neurosensory receptors resulting in reflex tearing. 
• Corneal pathology (i.e., keratitis and ulcer) stimulates the afferent corneal nerves of the reflex tearing arc. 
• Ocular inflammation (such as iritis) causes reflex tearing. 
• Megalocaruncle: An enlarged caruncle may cover the punctum, which prevents tear drainage.[6]

Conditions Affecting the Lacrimal Drainage System

• Conjunctivitis: Various conditions (such as allergy or infection) can trigger the inflammatory response that can lead to obstruction of the punctum and canaliculus. 
• Rhinitis or sinusitis. The inflammatory process may lead to acute or chronic nasolacrimal duct blockage.
• Punctal apposition syndrome. Apposition of the upper punctum to the lower punctum prevents tear drainage through the puncta.[6]
• Malpositioned punctum: The punctum should be apposed to the eyeball correctly. Even subtle eversion may cause tearing, especially in young patients, due to preventing tears from entering the canaliculi.[6]
• Punctal stenosis: Using drugs (such as glaucoma drops), trauma, or inflammatory diseases may cause punctal stenosis, which makes it difficult to drain tears. 
• Absence of puncta: This condition may be congenital or secondary to previous inflammatory disease. 
• Accessory punctum: Although most patients with this condition are asymptomatic, some may complain of tearing.[12]
• Dacryocystitis: Dacryocystitis consists of inflammation of the lacrimal sac, typically due to nasolacrimal obstruction. In acute cases, it manifests with erythema, swelling, tenderness at the medial canthus, and purulent discharge through the punctum when the sac is manually expressed. 
• Mucocele: This is a lacrimal sac full of mucus due to obstruction above or below the lacrimal sac.
• Absent or fibrotic sac. The sac's absence or fibrosis may result from prior surgery. 
• Canaliculitis. The inflammatory process affecting the canaliculus may impede tear drainage, which causes epiphora.  
• Sinus and nasal surgery: Surgeries performed in nearby structures can lead to inflammation of the lacrimal drainage system. 
• Neoplasms: Neoplasms originate from any part of the lacrimal drainage system and can obstruct it due to primary growth, or secondary, or metastatic spread. 
• Trauma: Scars from trauma may cause stenosis or obstruction of the lacrimal drainage system. Trauma can be iatrogenic (after orbital, nasal, paranasal, or craniofacial surgical procedures) or non-iatrogenic. 
• Intraluminal foreign bodies (such as dacryoliths) may obstruct lacrimal drainage. 
• Radiotherapy on the head and neck: Radiation triggers inflammation which can result in cicatricial nasolacrimal duct obstruction.[13]
• Systemic chemotherapy: Some systemic chemotherapeutic agents have been linked to tearing, such as 5-fluorouracil, docetaxel, and, less commonly, radioactive iodine, S-1, capecitabine, topical mitomycin C, and imatinib, which are responsible for punctum, canalicular, and nasolacrimal duct obstruction.[13][14]
• Bone marrow transplantation: This procedure can cause graft versus host disease, which causes inflammation, resulting in obstruction of the lacrimal drainage system. 
• Eye drops (such as glaucoma drops) may irritate ocular and peri-ocular structures, which results in punctal stenosis or eversion. Chronic irritation may also increase any subtle lubrication, pump, or drainage problem,
• Endogenous (autoimmune) inflammation (such as sarcoidosis, Wegener granulomatosis, Kawasaki disease, cicatricial pemphigoid, Stevens-Johnson, sinus histiocytosis, or scleroderma) - these conditions may lead to obstruction of the lacrimal drainage system.

Functional epiphora is a common term used in the literature to report epiphora in the presence of an anatomic patent lacrimal drainage system. However, there is no clear consensus about its diagnostic criteria and management.

Functional epiphora is a multifactorial disease whose management depends upon the suspected underlying cause or combination of causes. The suggested etiologies proposed by some authors include stenosis in the drainage system, lacrimal pump failure, edema at the nasolacrimal duct opening, tear hypersecretion, and nasal inflammation.[15] In contrast, for other authors, it is a diagnosis of exclusion.[16] 

In addition, the different tests used in various studies to diagnose this condition were often non-comparable due to the absence of standardization. Consequently, different techniques have been used to tackle the problem with variable results. Examples of these techniques are dacryocystorhinostomy, silicone intubation, insertion of Lester-Jones tube, injection of botulinum toxin A into the lacrimal gland, and lid tightening.[17][18][19][20]

Epidemiology

Tearing is a symptom that can occur at any age (from several weeks after birth until the elderly) as a manifestation of different conditions.

In children, congenital nasolacrimal duct obstruction at the valve of Hasner is the most common cause of epiphora.[21] However, the most common etiology of tearing in adults is unclear as there is significant variability between studies performed in different parts of the world. The top causes listed in the literature are dry eye, lower lacrimal drainage obstruction, punctal stenosis, and lower lid laxity.[3][22][23][24]

Most studies have detected a female preponderance in low lacrimal drainage obstructions.[2] It has been postulated that this could be due to anatomic differences affecting tear drainage and accumulation.[3]

Regarding laterality, unilateral tearing is more common in cases of a lacrimal obstruction than other causes, whereas bilateral tearing is more frequent in cases of reflex tearing.[3]

Pathophysiology

The mechanisms that cause watery eyes can be simplified as follows:

• Overproduction due to abnormal stimulation of the lacrimal gland: primary hypersecretion (rare) or reflex tearing
• Dysfunctional distribution of tears through the ocular surface
• Inadequate drainage is caused by an obstruction in any part of the lacrimal drainage system[25]

 The tear film is divided into three layers:

• Inner mucin: produced by the conjunctival goblet cells, adheres to the aqueous layer on the eye surface.
• Middle aqueous: secreted by the autonomically innervated lacrimal gland and the accessory glands of Krause and Wolfring.
• Outer lipid layer: produced by the meibomian and Zeiss glands - it reduces the evaporation of the aqueous layer.[26]

Any problems affecting any of these glands alter the correct composition of the tear film, which causes compensatory reflex hypersecretion.

In cases where the neurosensory receptors from the trigeminal nerve in the cornea and conjunctiva are stimulated (i.e., neuralgia, conjunctival disease, corneal disease, ocular inflammation, or eyelid inflammation), there is increased lacrimal gland secretion (reflex tearing). In addition, mechanical wiping of the tears can irritate the conjunctiva further, which causes reflex tearing and perpetuates the cycle.

Eyelid movement must also be normal to facilitate proper tear film circulation across the conjunctiva and corneal surface. Thus, the upper eyelid should move downwards, touching the inferior eyelid with each blink and consequently picking up the tear meniscus for its distribution vertically. Moreover, the orbicularis muscle (pretarsal and preseptal segments) should contract its fibers narrowing the palpebral fissure to spread the tear film toward the punctum. As a result, this blink circle facilitates tears circulation from the punctum through the lacrimal sac and down to the nasolacrimal duct.[6] Therefore, a healthy seventh cranial nerve-orbicular muscle unit, good eyelid position, and tone are required to complete tear film distribution across the ocular surface and down to the drainage path.

Once the tears enter the upper and lower puncta, they flow into a vertical portion before entering the horizontal part of the canaliculi that ends at the lacrimal sac in the lacrimal fossa. The tears then flow down the nasolacrimal duct to end at the inferior meatus of the nose.

An abnormality partially or completely blocking anywhere along this path usually causes epiphora. This epiphora not only depends on how complete the obstruction is but also on how many tears are produced. Therefore, younger patients may be more symptomatic than older patients as tear production decreases with age.

History and Physical

A thorough diagnostic workup is needed to identify the cause or combination of causes responsible for watery eyes. 

Chief Complaint 

Clinical history is one of the most important aspects of assessing a patient with a watery eye as it provides clues to identify the possible cause of this symptom. 

 The clinical history should include the following:

• The onset of symptoms. Tearing since birth in a child is often caused by an obstructive Valve of Hasner. However, tearing onset in an older child suggests a different etiology, such as an obstruction in the canaliculus. 
• Laterality. Unilateral tearing often indicates obstruction; in contrast, bilateral tearing mainly suggests reflex tearing. Some exceptions exist, such as bilateral puncta or canaliculi obstruction secondary to a viral infection or unilateral reflex tearing secondary to facial nerve palsy.  
• Intermittent or continuous course. Intermittent tearing in adults usually results from partial stenosis, dacryolithiasis, or reflex tearing. Persistent symptoms are usually due to complete outflow obstruction.
• "Tears on the cheek" vs. "tears stay in your eyes." True epiphora manifests with tears overflowing onto the cheek due to lacrimal drainage duct obstruction.
• Exacerbating or provoking factors: For example, worse tearing in cold air or wind may be caused by dry eye or partial lacrimal obstruction.
• Association with eating or chewing. This association suggests aberrant facial nerve regeneration ("crocodile tears").
• Associated ophthalmic symptoms:
• Itching. This suggests an allergic phenomenon.
• Grittiness and burning may suggest tear film instability (dry eye).
• Pain in the eye. Conditions such as keratitis, iritis, ulcers, or foreign bodies must be ruled out when there is a pain in the eye. 
• Pain at the site of the lacrimal sac: acute dacryocystitis should be ruled out.
• Photophobia: suspect corneal damage.

Constant tearing without foreign body sensation, grittiness, or pain suggests epiphora.

• Associated signs:
• Mucous discharge, particularly in the morning, suggests nasolacrimal duct obstruction.
• Bloody tears may be due to malignancy.
• Associated nasal symptoms.
• Use of ophthalmic medications.

Medical and Surgical History

• Systemic conditions such as craniofacial syndromes
• Lacrimal probing during childhood
• Past ophthalmic diseases or symptoms
• Prior surgical history:
• Lid or lacrimal surgery
• Sinus surgery
• Lid, facial or orbital trauma
• History of facial palsy
• History of dacryocystitis: prior episodes of dacryocystitis mean a nasolacrimal duct obstruction is present
• History of chemotherapy or orbital radiotherapy

Physical Examination

Physical examination focuses on demonstrating the patency of the drainage system and ruling out causes of reflex tearing.

• Examination of the face and peri-ocular area:
  • Inspect the patient's face for signs of skin diseases (such as rosacea, acne, eczema, ichthyosis, and scleroderma) or facial asymmetry (indicative of facial nerve palsy).
  • Examine the superolateral orbit for clues of lacrimal gland disease (enlargement, tenderness, erythema, or induration. 
  • Exclude orbital fat prolapse.
  • Check for spillage of the tears onto the cheek: medial spillage indicates impaired drainage, and lateral spillage suggests lower lid laxity.[5]
  • Assess for leakage from a dimple in the eyelid suggesting a congenital fistula.

• Examination of the eyelids:
• Contour. Any lump, cyst, or notch may irritate the ocular surface causing reflex tearing. 
• Laxity. This affects the pumping mechanism of the eyelids. Check for lid laxity with the lid snap test and lid distraction test.[27][28] 
• Position:
• Entropion (lid turns inward): Contact between the entropic eyelid and the ocular surface can result in ocular irritation and subsequent reflex tearing. 
• Ectropion (lid turns outward): The ectropic eyelid can cause watery eyes due to corneal exposure.
• Ptosis. Increased ptosis during cheek puffing indicates aberrant facial nerve regeneration.[29]
• Retraction. Upper or lower eyelid retraction may cause unsuccessful tear pumping and increase the ocular surface, which favors tear evaporation. 
• Closure of the eyes. Incomplete or defective eyelid closure (lagophthalmos) can cause tearing due to corneal exposure. 
• Blink. Check for blink frequency and the proper touch between the upper and lower eyelid with each blink.
• Associated diseases. Assess the lids for signs of blepharitis.
• Eversion. Evert the eyelids to rule out any foreign body irritating the eye or scars that indicate previous surgery, trauma, or trachoma. 
• Signs of previous eyelid surgery. Skin color changes or scars may indicate previous eyelid surgery contributing to tearing. 

• Examination of the eyelashes: examine the eyelashes for signs of blepharitis, meibomian gland dysfunction, or eyelashes turning in.

• Examination of the medial canthus: compare both sides for symmetry and check for fistulas, lumps (look for visual clues and palpate) or scars (indication of prior surgery).
• Dacryocystitis. Acute dacryocystitis presents with erythema, swelling, and tenderness at the medial canthus, with discharge through the punctum when the sac is manually expressed. No further testing is necessary to diagnose nasolacrimal duct obstruction in this case.
• Mucocele. In the case of a mucocele, palpation is necessary as many mucoceles are not visible.
• Malignancies in this region may mechanically obstruct the drainage system. 

• Examination of the conjunctiva: examine the conjunctiva for evidence of conjunctivochalasis, symblepharon, redness, follicles, papillae, foreign body, scars, or secretions.

• Examination of the cornea: examine the cornea to rule out any noticeable corneal pathologic changes, for example, the presence of punctate epithelial erosions in dry eyes or a corneal ulcer. Assess how much of the cornea is covered when the patient blinks spontaneously or closes her eyes.

• Examination of the tear film. Two crucial aspects of the tear film need to be assessed:
• Quantity. Examine the tear film lake before placing any drops. If the tear film lake is high, obstruction is usually present.
• Quality. Look for the existence of a foamy tear film, debris, and mucous. Debris floating in the tear meniscus suggests obstruction of the nasolacrimal duct. Conversely, high tear meniscus without debris indicates blocked puncta or canaliculi. 
• Examination of the punctum: 
• Check for its presence, size, number, and position during all stages of the blink cycle. Physical eversion of the eyelid is necessary to visualize the punctum on slit lamp examination. If the punctum is visible with no eversion of the eyelid, its position is abnormal.
• Examine it for evidence of inflammation or stenosis.
• Look for the presence of discharge, granules (suggesting canaliculitis or dacryocystitis), or bleeding (alerting to the possibility of malignancy).

• Examination of the canaliculi: 
• Check for signs of inflammation.
• Palpation may reveal any localized problems or the level of obstruction.
• Additional tests may help assess the patency of the canaliculi. 

• Examination of the nose:  Rhinoscopy helps rule out malignancy, hypertrophic mucosa, or nasal polyps that can obstruct the nasolacrimal ostium.[30]

Evaluation

When a physical examination does not determine the origin of the tearing clearly, different tests can help assess the watery eye. 

Secretory test. These tests help evaluate the increased tear production in reflex tearing or primary hypersecretion cases.

• Schirmer test. A Whatman filter paper (35 mm x 5 mm) strip is placed between the middle and lateral third of the lower lid, and the patient is instructed to keep the eyes open, blinking normally, for five minutes. The distance that is wetted in five minutes is recorded.[31]

• The Schirmer I test is performed without a topical anesthetic to assess basal and reflex tear production. 
• The Schirmer II test is performed with a topical anesthetic to assess basal tear production. 
• The Schirmer III test is used to measure reflex secretion. In this test, a topical anesthetic is not applied to the ocular surface. A cotton applicator is then applied to the nasal mucosa and used to stimulate the trigeminal nerve. Some literature sources list this as the Schirmer II test, while the Schirmer I and II are listed as IA and IB.[32]
• Fluorescein tear break-up time (FTBUT). This test assesses the tear film's stability, as an unstable tear film can trigger reflex tearing.[33] The inferior temporal bulbar conjunctiva is touched with a wet fluorescein staining strip for 1-2 s. The patient is subsequently asked to blink two to three times naturally to spread the fluorescein uniformly on the ocular surface. The tear film is examined from the last blink to the first dry spot using a cobalt-blue filter of a slit-lamp with 10x magnification; the average time of two or three consecutive readings is recorded as FTBUT in seconds. The FBUT is abnormal if less than 10 s. Although this is an easy test to perform, it has low reliability due to different operational and environmental factors.

Excretory test. These tests are used to report the lacrimal system patency and drainage function.

• Fluorescein dye disappearance test (FDDT): This physiologic test consists of staining the tear film using a fluorescein strip or instilling a drop of 2% fluorescein in the lower fornix. Observations of the residual fluorescence of the tear meniscus are made at 5 minutes, and the thickness of the tear meniscus is measured and graded on a scale that can be used to quantify the thickness subjectively. The scale range is 0 to 4+, with 0 representing no fluorescein dye remaining and +4 representing all the fluorescein dye remaining. A thin or no fluorescein remaining indicates a positive test and probable normal drainage outflow. This test is most valuable when both sides are compared simultaneously, which results in an asymmetric tear meniscus.[5] However, this test does not differentiate between anatomic and functional defects and gives no information on the site of the obstruction.[34] This rapid, simple, painless, and highly specific test can assist in assessing nasolacrimal duct obstruction, especially in children.[35]

• Jones dye test 1 (JDT1): In this physiologic test, a drop of fluorescein 2% is instilled in the lower conjunctiva. The patient is asked to blow each nostril separately in a tissue. Alternatively, a swab is inserted into the nose after 2 and 5 minutes. If the tissue or swab is not stained with fluorescein, the test is considered negative and likely to have an impaired drainage system. If fluorescein is obtained, the test is positive and may suggest there is no anatomic or functional blockage.[36] However, this test has a high rate of false-positive and false-negative results. The fluorescein passage into the nose varies from person to person and may take more time than expected despite the patent drainage system, which gives false-negative results. At the same time, a false-positive result can be obtained despite a mild anatomic obstruction.

• Jones dye test 2 (JDT2): This non-physiological test is performed in patients with negative JDT1. A small syringe is used to inject 1 mL of normal saline gently through a lacrimal cannula situated at the punctum. The test is positive if the fluid from the nose is deeply stained with fluorescein. A positive test indicates an incomplete obstruction in the nasolacrimal duct. In this situation, the patent lacrimal puncta and canaliculi enable the lacrimal sac to be filled with fluorescein, which flows down to the incomplete obstructed nasolacrimal duct. When the canaliculus is open but not functioning, the fluid obtained from the nose is clear (negative test) because the fluorescein has not reached the lacrimal sac. Failure to get fluid out of the nose indicates a complete obstruction in the lacrimal drainage system.[36]

• Lacrimal probing test: After topical anesthesia of the conjunctival sac, the lid is distracted laterally and kept under tension. At the same time, a Bowman probe is inserted gently vertically through the punctum and then horizontally through the canaliculus until a hard (lacrimal bone) or soft stop (tissue) is felt by the examiner. Bone is contacted when the probe passes through the lacrimal sac, which indicates a patent lacrimal system up to the lacrimal sac. Alternatively, when the probe's progress is impeded by soft tissue, stenosis or obstruction of the canalicular system is present. When there is a stop, the probe is clamped at the punctum. Then the distance to the clamp is measured to determine the length to the site of obstruction or stenosis. A calibrated Bowman probe may help to localize the site of obstruction more easily and accurately.[37] It is essential to keep the lid under lateral traction, which stabilizes the eyelid and stretches the canaliculus to facilitate passage of the lacrimal probe and avoid "soft stops" due to kinking of the canaliculus. Failure to recognize resistance to passing or incorrect technique can lead to trauma to the canaliculi resulting in a false passage or stenosis due to scarring in the injury area. In cases of acute dacryocystitis and acute canaliculitis, probing should be avoided. Active infection can hinder the passage of a probe, which increases the risk of iatrogenic trauma.

• Lacrimal syringing test (LST): After topical anesthesia of the conjunctival sac, the lid is distracted laterally and kept under tension. At the same time, a lacrimal cannula on a saline-filled 5-mL syringe is inserted gently vertically through the punctum and then horizontally through the canaliculus until a hard or soft stop. The plunger is then gently pushed down to flush the nasolacrimal duct with saline, and the degree and localization of reflux are recorded. The duct is anatomically patent if the saline flows into the nose or throat. Reflux via the same or contralateral punctum suggests stenosis or obstruction. While regurgitation through the opposite punctum means a block of the common canaliculus or more distal structures, reflux through the same punctum indicates obstruction of the ipsilateral canaliculus, and syringing must be repeated through the opposite canaliculus. Distension of the lacrimal sac suggests a nasolacrimal duct obstruction.[38] The lacrimal syringing test is commonly used in the clinic due to its simplicity and immediate results. However, the greater than normal positive hydrostatic pressure makes it unreliable for diagnosing nasolacrimal duct stenosis or functional delay. In addition, it has limited value in distinguishing the exact site of obstruction.[39]

• Optical coherence tomography (OCT), which uses the principle of low coherence interferometry, is gaining popularity in obtaining images from the punctum and canaliculus due to its noninvasive nature. However, its use is limited due to the lack of guidelines about standard terminologies, measurements, and image capture techniques. New modalities such as dynamic OCT and OCT dacryocystography will play an essential role in the future as they provide more extensive information about the anatomy, physiology, and pathophysiology of punctal and canalicular disorders.[40][41]

• Dacryoendoscopy: A dacryoendoscope is inserted through the lower or upper punctum. This leads to great detailed direct visualization of the proximal lacrimal drainage system (punctum and canaliculus).[42] It enables precisely locating pathologic changes affecting these structures and simultaneously can be used to perform surgical repair under direct visualization.[43]

• Nasal endoscopy: A rhinoscope is used to examine the nasal space to assess anatomic variations and to rule out nasal pathologies such as inflammation, polyps, and tumors.

• Dacryoscintigragphy (DSG): A 10-mL drop of technetium-99m radiotracer is instilled into the conjunctiva's lower fornix, and images are taken every minute for 45 minutes with a gamma camera. DSG is a noninvasive helpful technique to assess the functional patency of the lacrimal drainage system.[39] However, its limitations include its cost, long acquisition time, the low resolution to show the precise anatomic location, and the need for confirmatory procedures in the event it is abnormal.[44]

• Conventional dacryocystography (CDCG): This technique requires the injection of contrast media (lipoidal, iohexol, iopamidol) in the superior or inferior canaliculus to obtain posterior and lateral radiographs. CDCG provides more extended information about the anatomy of the lacrimal drainage system, which helps localize the site of obstruction. Currently, its use is limited to atypical cases. Disadvantages include the use of ionizing radiation and contrast media, lack of information about the surrounding bony structures, inability to assess the tear flow dynamics, and a limited view of the proximal lacrimal system.[45]

• Digitally subtracted dacryocystography (DS-DCG): This technique leads to bone-free images of the lacrimal drainage system after injecting contrast media (iohexol, iopamidol, sinograffin) in the superior or inferior canaliculus. DS-DCG is indicated in complex lacrimal disorders. Disadvantages include the use of ionizing radiation and contrast media, lack of information about the surrounding bony structures, inability to assess the tear flow dynamics, and a limited view of the proximal lacrimal system.[45] Despite these limitations, it is considered the gold standard technique for evaluating obstruction of the lacrimal drainage system.

• Computed tomographic dacryocystography (CT-DCG): This technique involves obtaining axial and coronal (1-2 mm thickness) computed tomographic images after using contrast media. The contrast media (iohexol, iopamidol) could be injected in the inferior or superior canaliculus or applied topically every minute for five minutes or three times at 0, 5, and 10 minutes. The main advantage is the information about the surrounding bony structures, which is relevant in assessing nasolacrimal obstructions in cases of maxillofacial trauma, congenital craniofacial deformities, previous surgery, lacrimal drainage tumors, and associated sinus disease. CT-DCG is the technique of choice when the bony anatomy is vital for pre-operative planning. Limitations include higher ionizing radiation exposure than DCG, contrast use, poor visualization of the common canaliculus, and inability to assess the dynamic tear flow. Currently, a reduction in ionizing radiation exposure could be attained using cone-beam CT-DCG with similar good images of the lacrimal drainage system.[45]

• Magnetic resonance dacryocystography (MR-DCG): It uses fast sequence techniques and fat suppression to obtain good-quality images of the lacrimal drainage system. Gadolinium contrast is used by cannulation or topical instillation (one drop every minute for five minutes or one drop every three minutes for 15 to 20 minutes). Alternatively, normal saline or normal saline mixed with 0.5% lidocaine and a balanced salt solution can be used.[45] Advantages include acquiring a series of images and no radiation exposure. In contrast, the main limitations are poor bone visualization, long acquisition time, motion artifact, difficult visualization in case of mucosal and paranasal sinuses disease, and a high cost. Dynamic MR-DCG can capture the passage of contrast media across the lacrimal drainage system, which makes it helpful in evaluating functional epiphora.[40]

Treatment / Management

Specific treatment will vary according to the etiology of the watery eye and coexisting exacerbating factors.

In general, when there is a problem with one of the tear film layers or in the distribution of the tears through the ocular surface, the condition may improve with medical management (such as using artificial tears and lubricating ointments). In cases of tearing due to eyelid laxity, lower eyelid tightening surgery is useful, although the effect does not always last.[46] When eyelid retraction or incomplete blink amplitude is the problem, options include placing a gold weight on the upper eyelid and aggressive lubrication.[6] Cases of a patent lacrimal system and well-positioned puncta have been managed with lower eyelid tightening and dacryocystorhinostomy with variable results.[47]

In the case of true epiphora, when the obstruction is a cause, surgical treatment is often required to restore drainage. The appropriate procedure is chosen based on the specific site of obstruction. Punctal stenosis is managed with perforated punctal plugs, punctoplasty or punctum dilatation, and positioning of a monocanalicular or bicanalicular stent.[48] In cases of proximal and mid-canalicular obstruction, dacryocystorhinostomy with retrograde intubation is the technique of choice, whereas, in distal canalicular obstructions, bypass surgery is advised. For common canalicular obstructions, when there is a proximal obstruction, canaliculodacryocystorhinostomy is used. However, when the obstruction is distal, dacryocystorhinostomy with membrane to my and intubation is more effective. In cases of no patency, bypass surgery with a Lester Jones tube is the technique of choice.[48] And when the obstruction is situated in the nasolacrimal duct, dacryocystorhinostomy will offer the best results.

• Punctoplasty consists of surgical enlargement of the punctum.
• Conjunctivodacryocystorhinostomy bypasses the canaliculi and the lacrimal sac due to the creation of a new direct passage of tears from the conjunctiva to the nasal space with the help of bypass tubes.
• Dacryocystorhinostomy is a surgery that creates a direct passage from the canaliculi to the nasal space by incorporating the lacrimal sac with the nasal mucosa after removing the bone adjacent to the lacrimal sac.
• Dacryocystorhinostomy with retrograde intubation consists of performing an external dacryocystorhinostomy and, after identifying the common canalicular opening in the lacrimal sac, inserting a silicon tube from this common internal opening out to the punctum.

Differential Diagnosis

In patients with a complaint of tearing, a detailed differential diagnosis should be made of the possible causes or combination of causes of a watery eye mentioned above. Some authors differentiate between "true epiphora" (obstruction of the lacrimal drainage system) and a watery eye (caused by tear film or blinking problems) to make this differential diagnosis easier by dividing the possible causes under these two possible results.

In a child with a tearing eye, one should consider the possibility of congenital glaucoma in addition to the etiologies mentioned above. The elevated intraocular pressure in this condition causes tearing, redness, photophobia, and enlargement of the eyes (buphthalmos).

Prognosis

A watery eye may significantly affect the patient´s quality of life as it may cause social embarrassment and interfere with daily activities such as reading and driving.[49] It may also cause chronic irritation of the periorbital skin due to repeated wiping away of the tears and the interaction of the salty tears on the skin. Most patients may improve their symptoms after the appropriate diagnosis and treatment.

Complications

It should be noted that a watery eye is not always only a discomforting symptom as it can be the manifestation of pathologies that can cause permanent ocular damage or complicate intra-ocular surgeries if left untreated.[23]

Pearls and Other Issues

• Watery eyes may have a marked adverse impact on the patient´s quality of life. 
• A thorough clinical history is essential in assessing watery eyes as it provides clues about the possible etiology and enables selecting the proper test for confirmation.
• A systematic physical examination is recommended as a combination of different factors may cause watery eyes. 
• Before treating an obstruction surgically, it is advisable to address hypersecretion and distribution problems first.

Enhancing Healthcare Team Outcomes

While optometrists and ophthalmologists are almost always involved in caring for patients with watery eyes, consulting with an interprofessional team of specialists, including an otolaryngologist and a radiologist, is essential. The radiologist plays a vital role in interpreting the radiologic images. In contrast, the otolaryngologist is crucial in diagnosing nasal pathology as the cause of watery eyes and contributes to the surgical management of lacrimal drainage obstructions. 

Family physicians and nurses also have an essential role in assessing this pathology, as they are often the first port of call for patients complaining of watery eyes.