The tear gland orLacrimal Gland (each eye has one of them) is located inside the upper lids above each eyeball andalong with accessory tear glands Krause and Ciaccio which are located under the eyelids, cause the secretion of aqueous part of teardrops.In general, the various layers of tear include:
- The thinnest innermost layer which is the mucin layer (or mucous layer) is derived and secreted from the conjunctival cells.
- The middle layer is the thickest layer and is actually like a diluted solution of water and salt.It is secreted by the lacrimal gland and the accessory glands. This layer is responsible for keeping the eyes moist and dislodging dust and foreign objects. Problems in the secretion of this aqueous layer of the eye is the most common cause of the eye dryness. This disease is also called “keratoconjunctivitis sicca”.
- The outermost oily layer (or lipid layer) is the most superficial and is derived principally from the meibomian glands. It prevents the evaporation of its underlying watery layers.
Tears flow over the surface of eye, then through tiny holes (punctum) located in the corners of upper and lower eyelidsdrain into lacrimal ducts and ultimately lacrimal sac. From there, tears travel down a duct (the nasolacrimal duct) draining into your nose.This is why when we cry,we suffer from a runny nose. So as you can see in the image below lacrimal system includes main andaccessory lacrimal glands, lacrimal ducts, the lacrimal sac and the nasolacrimal duct.
What is nasolacrimal duct obstruction?
It is the blockage of the thin nasolacrimal ductsthat prevents tears from draining normally and may be either congenital or acquired. Here, we discuss the congenital type.
What causes congenital nasolacrimal duct obstruction?
Congenital nasolacrimal duct obstruction is common in children. 6-10% of children are born before their tear ducts are fully developed. Some sources indicate thatthe prevalence of this disorder in newborns is 50%. The cause of this obstruction is theresidual membrane tissue at the end of the nasolacrimal duct.
What are the signs/symptoms ofcongenital nasolacrimal duct obstruction?
Babies who have blocked tear ducts usually have symptoms within the first 2- 6 weeks after birth, the most common one is excessive tearing. During the first month after the birth we do not have reflexive tear secretion (shedding tears), unless it is most likely pathologic (due to illness). Other symptoms include recurrent inflammation of the conjunctiva, swelling and infection in lacrimal sac which in this case eyelids and the area around the nose become red, inflamed and sensitive to touch. Also,this area may become swollen and yellow mucus can build up in the corner of the eye. In one third of cases this involvement is bilateral. The symptoms are typically aggravated by dust and wind, but there is no fear of light (photophobia).
Note: In Children who suffer from tearing and photophobia, congenital glaucoma should be considered.
How is a blocked tear duct diagnosed?
- With mild pressure on the lacrimal sac, liquid comes out of lacrimal pores (puncta).
- Special materialssuch as fluorescein are placed in each eye and based on how quickly they disappear or remain inoral pharyngeal cavity (which is evaluated with cobalt blue light), your doctor can judge about the presence or absence of obstruction.To perform this diagnostic tests,one drop of fluorescein 1% is placedin the conjunctiva and then we wait between 2 to 5 minutes. In normal conditions, after 5 minutes, almost no fluorescein could be remained in the eye.A baby’s tear ducts
Most of the times, ababy’s’ tear ducts obstruction will spontaneously get better. In 90% of children, most blocked ducts clear up on their own by 1 year of age.Interventional treatment of this disease include non-surgical and surgical procedures.
- Conservative Treatment (Non-surgical):This includes monitoring, the lacrimal sac massage and topical antibiotics. For massage, you should wash your hands, and then use your fingertip on the medial canthal region and press with a downward motion.You may also be asked to use a warm compress. If there is an infection, using a topical antibiotic ointment or drops may be helpful. Note that antibiotics do not removethe obstruction.
- Probing:If the tear duct obstruction does not resolve after several months of treatment, a severe infection occurs, or your child undergo recurrent infections, probing should beperformed. While this method is successful in 85-95 % of cases in children younger than one year,astheir age increases, the success rate decreases. Probing surgery is a surgical procedure that takes approximately 10 minutes and involves passing a thin metal probe through the blocked punctato remove the obstruction. Some doctors believe that the age of six months,in which probing can be performed without general anesthesia at the clinic,is the best age for this procedure but some believe that it is better to postpone it until the child is one years old so that the maximum chance of spontaneous urethral could be given to the child. When the child is one year old, probing is done in an operating room under general anesthesia.
- Intubation: If probing is unsuccessful, or while probing a stenosis (narrowing of the lumen and thin) is found, there may be a need for more extensive surgical procedures such as silicone tube intubation. In this method, a silicone tube is threaded through puncta to dilate the duct. They are generally left in for about six months, and then will be removed during a minor surgery.
- Balloon Dacryoplasty: A more recent surgical procedure is Balloon Catheter Dilation, in which a balloon is inserted into the corner of the eye and the tear duct. Initially, the balloon is inflated by a sterile fluid for 90 seconds and then is deflated. It is again inflated for 60 seconds and then finally the liquid is removed. It is reported that the successrate of this procedure is between 80-100%.
- Dacryocystorhinostomy (DCR):In rare cases, when despite the above treatments children still suffer from tearing, DCR or Dacryocystorhinostomy may be performed in children too.
This method,which is the main treatment in most patients with acquired obstruction, is also used in people who suffer from recurrent dacryocystitis, mucoid fluidreturn, and painful enlargement of the lacrimal sac or bothersome tearing. Although there are many different ways to treat this problem, but the basic technique in all of them involves opening up a path passing through the lacrimal sac to nose