Background
The lacrimal and accessory lacrimal glands produce tears. The lacrimal glands are located in the upper/outer quadrant of the orbit and produce "reflex" tears when the eye is irritated or stimulated by emotion. The accessory lacrimal glands are scattered along the conjunctiva of the eyelid and produce the tears that keep the eye moist.
Tears consist of three layers that are produced by glands in the eyelids. The glands of Wolfring produce the inner mucinous portion, the lacrimal gland and gland of Krause secrete the middle aqueous portion, and the meibomian glands produce the outer lipid layer. The middle watery layer is the majority of the tear.
Tears function to prevent drying of the cornea, smooths the refractive surface of the eye, lubricate the ocular surface for eyelid closure and protect from infection via secretory antibodies.
Tear system consists of lacrimal gland (a), punctums (b,e), canalicules (c,f), lacrimal sac (g,d). Tear is then drained through nasolacrimal duct (not shown in the image) into nasal cavity https://en.wikipedia.org/wiki/Nasolacrimal_duct_obstruction
The tears flow to the upper and lower puncta located in the upper and lower eyelid margins near the medial epicanthus. The puncta open into the upper and lower canniculi, which join the common canniculus, which empties into the lacrimal sac. The lacrimal sac enters the vertically placed nasolacrimal duct that enters the nasal cavity.
Nasolacrimal duct obstruction, or dacryostenosis, is the most common cause of persistent tearing and ocular discharge in children. It occurs in up to 20% of newborns, with 5% presenting with symptoms within the first year of life. Most obstructions occur where the nasolacrimal duct enters the nasal cavity, the membrane of Hasner. The nasolacrimal ducts appears in the 3rd-5th week of life and the epithelium of the cord gradually extends from the eyelids to the nose. Canalization of the duct begins during the 3rd month of intrauterine life and incomplete canalization results in obstruction. There may be epithelial debris leading to obstruction and in rare cases, the entire apparatus is not present. Presentation may be from birth to weeks and months later. 30% of cases are bilateral.
Presentation and Treatment
A child may present with persistent tearing, debris on eyelashes, and sometimes conjunctival redness. This rarely bothers infants and the condition is not painful. According to a recent study, treatment has shifted to watchful waiting until age 1 because of the high spontaneous resolution rate. Persistent obstruction beyond 1 year of age warrants probing as a first-line therapy.
If conservative management fails, persistent CNDO beyond 1 year of age should be managed either by further observation or by primary probing according to the severity of symptoms. In patients in whom probing fails, advanced treatment such as balloon catheter dilation, silicone tube intubation or dacryocystorhinostomy may be considered. In a prospective observational study of NLD probing of 900 eyes in 672 children between six months and four years of age, probing was successful in 78 percent.
Dacrocystitis
This is an infection of the lacrimal sac usually associated with obstruction of the nasolacrimal duct system. May present with systemic symptoms and there will be a tender red elevation medial to the lower lid. Should be treated with hot packs and oral antibiotics. Usually will require probing after resolution.
Mucocele of the Lacrimal Sac
If there is obstruction of the lacrimal system at the upper and lower portions, there may be an accumulation of fluid in the lacrimal sac. This will present as a bluish mass below the medial epicanthus. Hot compresses and massage is the initial treatment and most infants will require probing
References
- Takahashi Y, Kakizaki H, et al. Management of congenital nasolacrimal duct obstruction. Acta Opthalmol. 2010; 88(5): 506-513
- Repka MX, Chandler DL, et al. Primary treatment of nasolacrimal duct obstruction with probing in children younger than 4 years. Opthalmol. 2008; 115(3):577
- Prasad, Sudha. Congenital Nasolacrimal Duct Obstruction. Pediatrics in Review. March 1994
- Wagner, r.S. Natural History of Nasolacrimal Duct Obstruction Pediatrics in Review March 1989