Epiphora: Diagnosis and Treatment Lacrimal Apparatus
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Epiphora: Diagnosis and treatment Lacrimal apparatus FRANK J. DITTRICH, D.O. Mount Clemens, Michigan levator palpebrae superioris muscle. The lar- ger, almond-shaped orbital lobe has from two Tearing is a necessary protective function to five ducts which traverse the smaller, pal- in which about 1 ml. of fluid is secreted pebral part of the lacrimal gland. This is by each eye every day and carried away situated just above the lateral part of the through the nasolacrimal ducts. There upper fornix and can be seen through the are several causes for the overflow of conjunctiva when the upper lid is everted. tears onto the cheeks, but the most common Small ducts from the palpebral portion join is obstruction of the puncta lacrimalia those from the orbital portion to open by from in newborn infants in whom the membranes 10 to 12 small orifices just anterior to the la- have not disappeared. In elderly persons, teral part of the upper fornix, about 4 or 5 on the other hand, ectropion often is due mm. above the superior border of the upper to atrophy of the orbicularis oculi and tarsus palpebarum. Because the ducts from the loss of elasticity of the skin. Other orbital lobe pass through the palpebral lobe, causes include fungal infection, often the removal of that lobe prevents tears from unilateral, and traumatic laceration of reaching the eye. a canaliculus. Diagnostic and therapeutic In addition to the principal gland are the measures for epiphora are described and glands of Krause and Wolf ring, which are their indications are considered. accessory lacrimal glands located between the fornix and the upper border of the tarsus of each eyelid. The blood supply to the lacrimal gland comes from the lacrimal artery, a branch of the oph- thalmic artery. A corresponding vein drains The Dictionary of Visual Science has defined behind the superior and inferior ophthalmic epiphora as "an overflow of tears onto the veins. The lymphatic drainage is to the pre- cheek caused by excessive lacrimation, by ob- auricular lymph nodes via the conjunctival struction of the lacrimal ducts, or by ectro- lymphatic vessels. pion." This paper will deal with the detection The innervation of the lacrimal gland con- and management of this lacrimal malfunction sists of sensory input via the lacrimal nerve after a brief review of the normal anatomy and branches of the ophthalmic division of the tri- function of the lacrimal apparatus. geminal nerve. The motor output is via the parasympathetic fibers of the greater super- Anatomy ficial petrosal nerve and the pterygopalatine A distant relative of the salivary gland, the ganglion. Sympathetic fibers to the lacrimal lacrimal gland is a tubuloracemose structure gland arise from the superior cervical gang- derived from ectoderm. It rests above and la- lion. (Paralysis of the sympathetic nerves teral to the eyeball in a bony fossa just under causes an increase in tears, while paralysis of the roof of the superior outer portion of the the facial nerve causes suppression of tears.) bony orbit. It weighs about 0.78 gram and There is also a hypothalamic-limbic lobe cor- measures 20 by 12 by 5 mm. It is partially tical regulation of tearing, manifested by emo- divided by the expanding aponeurosis of the tional or psychic crying. 755/111 Journal AOA/vol. 73. May 1974 Epiphora The tears produced by the lacrimal gland during embryonic life, and in 2 percent of in- serve their purpose and are carried away by fants it fails to disappear shortly after birth. the lacrimal drainage system.2 A flowing tear This causes epiphoric symptoms. Rupture of on its way to the nasal exit first encounters this membrane usually can be felt during prob- the puncta. These are rounded or oval aper- ing of the region in a young infant. tures that sit atop a slight elevation, the lac- rimal papilla. The papillae are paler than the Physiology rest of the lid margins, and this aids in their Contrary to popular belief, newborn babies identification. The puncta are about 0.3 mm. do secrete tears. Close inspection of the con- in diameter. The upper one is about 6 mm. junctivae of newborn infants will show them from the medial canthus, the lower one about to be moist, and they rarely suffer from con- 6.5 mm. from the medial canthus. Both puncta ditions due to a hypolacrimation. Apt and point slightly backward into the lacrimal lake. Cullen• found that more than 80 percent of In about 30 percent of newborn infants the newborn infants secreted adequate amounts puncta are closed.3 In persons at the other of tears when they were crying, and 96 per- end of the age scale, the lacrimal papillae are cent had normal tearing when they cried. prominent because of atrophy of the orbicu- These percentages are similar to those of nor- laris oculi muscle. Weakness of this muscle mal adults. plus loss of elasticity of skin leads to senile As might be expected, a tear is a heterogen- ectropion, a frequent cause of epiphora. ous fluid closely resembling plasma; its osmotic By action of the capillaries and the lacrimal composition is equivalent to 0.9 percent sodium pump,4 which will be explained shortly, tears chloride, and its pH is the same as that of pass through the puncta into the vertical ca- blood, 7.35. Tears contain similar elements naliculus, which is about 2 mm. in length, to those of blood, that is, protein, sugar, urea, with a lumen that soon widens to form an and sodium chloride. In fact, investigators in ampulla. From here the tears travel in a me- Boston,® using the modified Schirmer test with dial direction along the horizontal canaliculus Clinistix, were able to correlate the amount for from 8 to 10 mm. to reach the common of glucose in tears with the amount in blood canaliculus, also termed the sinus of Maier. in the hypoglycemic state. The average glu- This common channel pierces the lacrimal cose concentration in tears of normal subjects fascia to enter the lacrimal sac 2.5 mm. below was found to be from 1.0 to 7.2 mg./100 ml. its apex. Although the apex of the lacrimal In a study of 200 diabetic patients, 119 of sac lies above the medial palpebral ligament whom had blood sugar levels above 160 mg./ (actually a tendon joining muscle to bone), the 100 mI.,7 85 percent had enough glucose in common canaliculus enters the sac beneath this their tears to yield a positive Clinistix reaction. important landmark. The most important ana- Tears contain the bacteriostatic enzyme tomic relation of the lacrimal sac is to the lysozyme, which was first described in 1922 anterior ethmoid air cells, which lie just medial by the discoverer of penicillin, Sir Alexander to the lacrimal sac. Fleming. Lysozyme protects the eye by hydro- The nasolacrimal duct is a downward con- lyzing the beta 1-4 linkage of the mucopolypep- tinuation of the lacrimal sac. It averages about tide substance found in the cell wall of po- 15 mm. in length and slants back and slightly tentially harmful bacteria,8 and damage occurs laterally. Lateral to the nasolacrimal duct lies when the amount of lysozyme in the tears is the maxillary sinus. The nasolacrimal duct low. The lysozyme content was found to be empties into the inferior meatus beneath the low or absent in industrial workers and cit- inferior turbinate about 10 mm. posterior to izens working or living in smog-polluted at- its anterior tip. At this terminus of the lac- mosphere. The lysozyme content is diminished rimal apparatus is the most common cause of also in patients suffering from keratoconj unc- epiphora in infants. A thin membrane closes tivitis sicca or Sjogrens syndrome, and in the intranasal end of the nasolacrimal duct those at both ends of the age scale (Table 1). 756/112 The normal person secretes about 1 ml. of TABLE 1. AVERAGE LYSOZYME CONTENT OF TEARS OF tears from each eye per day, and the principal PERSONS OF VARIOUS AGES.° function of tears is to keep the eye moist and mcg./ml. constantly to flush away noxious particles. Infant, 15 days to 1 year 850 Jones9 divided the secretory system between Child, 1-10 years 2,000 basic and reflex secretors. Three sets of glands Adult, 10-40 years 1,750 comprise the basic secretors, and these contri- Adult past 80 years 800 bute to the composition of the tear film, which consists of three layers. The first or innermost layer of tear film is made up of mucin secreted by the goblet cells the circuit, a flood of tears occurs in an at- of the conjunctivae, the glands of Henle found tempt to wash away the irritating stimulus. in the inner third of the upper and lower tar- Reflex secretion can be divided into periph- sus, and finally the mucin-secreting glands of eral sensory, retinal and central sensory, and Manz in the circumcorneal ring of limbal con- psychogenic. Peripheral sensory reflex lacri- junctivae. mation occurs via the route just described Second is the middle or lacrimal layer, which whenever there is an irritating stimulus to comes from the accessory lacrimal glands of the conjunctiva, cornea, uvea, nasal mucosa, Krause, of which there are about 40 in the and those structures innervated by the affer- upper fornix and six in the lower. The acces- ent sensory fibers of the fifth cranial nerve. sory lacrimal glands of Wolfring also contri- Retinal stimulation of reflex lacrimation bute to the middle layer of tear film, and there occurs whenever photophobia is present or may be secretions from an occasional acces- whenever intense light enters the eye.