Epiphora

Excerpt

Patients will frequently present with "a watery eye" or "a tearing eye." Historically, this was called epiphora, but there have been recent variations in the use of different terms.

Lacrimation (or lachrymation) is derived from "lacrima," Latin for tear, and essentially means "production of tears," although it is often used to describe the "shedding of tears" or to cry. Lacrimation may be basal (basic tear production), reflexive (to stimuli such as surface irritation, glare, corneal ulcer, corneal exposure), and psychic (emotional). It is thought that animals do not exhibit emotional lacrimation, although recent observations of elephant mothers responding to their dead offspring have reignited this debate. The sympathetic innervation to the lacrimal gland is thought to stimulate basal tear secretion. Basal tear production decreases with age, resulting in progressive acinar atrophy, fibrosis, and lymphocytic infiltrates. Normal basal tear production is 2 microliters per minute (10 ounces per day). It may be stated that lacrimation, whether used to imply the "production of tears" or tearing from emotion or stimuli, implies the production of tears in a normal person without and blockage of the excretory system.

Epiphora

English texts from at least 1475 have used epiphora to mean tearing or excessive tearing. It essentially means an abnormal overflow of tears from the eye onto the face. The cause is not specified. Lately, there has been a tendency to apply the word epiphora only to tearing caused by an obstruction. This does not have any historical accuracy, and the temptation to use it in this manner should be resisted.

The word derives from ancient Greek epifora: "epi" means "on," "upon," or "in addition," and "phérein," meaning "bring" or "carry." The literal meaning of the word epiphora is "to bring upon." This symptom is known to have been described in Egypt (1500 BC) and by Hippocrates (460 BC to 370 BC). Epiphora applies to excessive tearing caused by excessive tear production or secondary to poor drainage. Epiphora is sometimes subdivided into

1. Gustatory epiphora ("crocodile tears" caused by aberrant nerve regeneration)

2. Reflex epiphora (reactive tear production caused by any ocular surface trauma or stimulation)

3. Obstructive epiphora (punctal, canalicular, lacrimal sac, or lacrimal duct occlusion)

4. Hypersecretory epiphora is the production of excessive tears. This is very rare.

Plerolacrima

Patients often present with the complaint that they have "a pool of tears in the eyes that interferes with vision," but not frank epiphora. This is also sometimes seen in patients after a dacryocystorhinostomy, where the tear flow may be improved, but the obstruction is not completely corrected. Ian Francis, a classically trained and thinking surgeon, coined the term "plerolacrima" in 2002. He derived it from the Greek "plero" (meaning full) and the Latin "lacrima" (tears). He noted that it was a similar derivative to the one H. M. Traquair of Edinburgh coined in 1927: "plerocephalic edema" to indicate optic nerve edema caused by raised intracranial pressure. We feel this is a useful term that completes the types of excessive tearing or pooling of tears that bother patients and is deserving of an addition to our medical lexicon.

Symptoms: Epiphora can cause blurry vision, discharge if there is a lacrimal sac infection, mucoid discharge if there is a canalicular foreign body, eyelid skin excoriation from constant wiping and laxity of the lower eyelids from constant wiping

The tear film is comprised of three layers:

1. an innermost mucin layer produced by goblet cells of the conjunctiva, which are found mostly in the fornices

2. an aqueous layer produced by the lacrimal glands and a minor portion from the accessory lacrimal glands of Wolfring and Krause.

3. an outermost lipid layer produced by the meibomian glands and Zeis and Moll glands (found on the eyelid margin).

The mucin layer creates a wettable surface on the cornea. The aqueous layer provides a smooth surface and hydration. The lipid layer reduces surface tension and increases tear break-up time. Tears are secreted at a basal rate as well as reflexively in response to stimuli. Dysfunction of any of these components contributes to surface disease and abnormal tearing, resulting in discomfort, altered light refraction, and blurred vision.

The lacrimal system has secretory and excretory components. Normally, there is a balance between tear production and drainage. When this balance is affected, either the secretory or the excretory component may produce epiphora.

The secretory lacrimal system produces tears. The main lacrimal gland is located in the lacrimal fossa of the frontal bone, divided into orbital and palpebral lobes by the lateral horn of the levator aponeurosis. Accessory lacrimal glands are located in the fornices and eyelids. The trigeminal nerve, the facial nerve, sympathetic innervation, and parasympathetic innervation stimulate tear production from the lacrimal glands.

The Secretory System is composed of (fig 1)

1. The Main Lacrimal Gland

   1. The orbital lobe

   2. The palpebral lobe

2. Accessory Lacrimal Glands

   1. Glands of Krause

   2. Glands of Wolfring

3. Mucin Secretors

   1. Goblet cells

   2. Glands of Manz

   3. Crypts of Henle

4. Oil Secretors

   1. Meibomian glands

   2. Glands of Moll

   3. Glands of Zeis

The anatomical excretory lacrimal system drains tears. Tears drain from the ocular surface via puncta in the lower and upper eyelids, into the ampulla, and then through the canaliculi. In 90% of people, the upper and lower canaliculi join to form a common canaliculus. The canaliculi drain into the lacrimal sac, followed by the nasolacrimal duct, which opens in the inferior meatus of the nose. Blockage can occur within any of these components. Both positive and negative pressure systems have been proposed as mechanisms of tear flow through the excretory lacrimal system.

The anatomical excretory system (the punctum, the canaliculus, and the common canalicular opening are termed the upper lacrimal system, and the lacrimal sac and the nasolacrimal duct are termed the lower lacrimal system) is composed of (figs 2, 3):

1. The puncta

2. The canaliculus

   1. Vertical component 2 mm upper and 2 mm lower

   2. Horizontal component 8 mm upper and 10 mm lower

   3. Common canalicular opening into the lacrimal sac

3. Lacrimal sac

   1. 12 to 15 mm vertical height

   2. 4 to 8 mm anteroposteriorly

   3. 3 to 5 mm in width

   4. One-third of the lacrimal sac is above the medial canthal tendon.

4. Nasolacrimal duct

   1. Measures 12 to 18 mm

   2. The nasolacrimal duct angulates 15% posteriorly and 15 to 30 degrees laterally.

5. Valves and sinuses

   1. Valve of Bochdalek

   2. Valve of Folz

   3. Sinus of Maier

   4. Valve of Rosenmuller is the angulation of the common canaliculus as it enters the lacrimal sac

   5. Valve of Krause

   6. Valve of Hyrtl

   7. Valve of Hasner is the most important valve as an imperforate membrane here causes congenital nasolacrimal duct obstruction

   8. Lacrimal sac and duct diverticula

Functional Excretory System

As one blinks, the orbicularis oculi muscle contracts: the pretarsal and preseptal orbicularis muscles each have a deep medial head. The contracture causes dilatation of the lacrimal sac and a suctioning effect. The lower eyelid rides upwards, and the punctum moves inwards. Tears are drawn into the punctum, canaliculus, and lacrimal sac by this pump mechanism. This pump mechanism is disturbed in the presence of facial nerve palsy.