The lacrimal drainage system consists of the upper and lower lacrimal puncta, which continue as lacrimal canaliculi. The canaliculi then open into the lacrimal sac which drains the tears into the nasolacrimal duct and subsequently into the nasal cavity.
The lacrimal drainage system drains the tears and secretions from the eye into the nasal cavity. They can be affected by congenital malformations evident at birth, pathological processes or trauma. Drainage disruption causes accumulation of tears in the conjunctival sac – epiphora, and secretion in case of infection. The function of the lacrimal drainage system is evaluated by the Fluorescein dye disappearance test (FDDT, FDT). After instilation of one drop of fluorescein into the conjunctival sac the presence of residual dye is assessed. In case of no residual dye the drainage is normal (FDT grade 0). If the fluorescein remains partially in the conjunctival sac (FDT grade 1) or completely (FDT grade 2) the drainage is disrupted (Fig. 2). In these cases it is necessary to examine the lacrimal pathways. The FDT is an exact test and can be performed already in infants (Fig. 3).
According to the location, the disorders of the lacrimal drainage system can be divided to the pathologies of the canaliculi, lacrimal sac, nasolacrimal duct and nasal cavity.
Disorders of the lacrimal canaliculi
The lacrimal canaliculi are predominantly affected by inflammations causing secretion from the canaliculi and epiphora. The canaliculi are also the most common site of a lacrimal pathway trauma due to their superficial location and exposition to the outer environment. If the trauma or inflammation cause stenosis or complete obstruction (obliteration) of the canaliculi up to 3 mm, it is possible to dilate the stenotic parts or remove the obstruction with stenting of the affected site with a silicone cannula (intubation) for 3 months. In case of more extensive scarring, if the unobstructed part of the canaliculi is at least 7 mm long, it is possible to remove the affected part surgically and re-attach the unobstructed part to the lacrimal sac which is then opened into the nasal cavity. This procedure is called canaliculodacryocystorhinostomy. In case the unobstructed part of the canaliculi is less than 7 mm long their preservation is not possible and it is necessary to create an artificial drainage pathway between the conjunctival sac and the nasal cavity. This procedure, conjunctivodacryocystorhinostomy (CDCR), is based on insertion of a special glass cannula called Jones tube (Fig. 4, 5). The tube remains permanently in the stoma. It is necessary to clean it regularly which is difficult for the children, therefore the CDCR is performed only in patients older than 10 years.
Lacrimal sac and nasolacrimal duct disorders
Disorders of the lacrimal sac are not very frequent. The sac is usually affected by acute or chronic inflammation (dacryocystitis) or dacryolith formation (dacryolithiasis). On the other hand the nasolacrimal duct is the most common site of lacrimal pathologies. In children the most common disorder is the congenital nasolacrimal duct obstruction (See Congenital lacrimal obstruction), in adults the obstruction is acquired, usually resulting from inflammation or trauma. The obstruction is treated by stenting of the nasolacrimal duct with a silicone cannula (intubation) or creation of an artificial connection (stoma) between the lacrimal sac and the nasal cavity, i.e. superior to the site of obstruction (Fig. 6). This procedure is called dacryocystorhinostomy (DCR) and it can be performed from the side of the face (external approach DCR) or from the side of the nasal cavity (endonasal approach DCR, EDCR).
We have created a system of diagnostic procedures and treatment of the lacrimal drainage system which is unique in the Czech Republic. Up to 2016 we have examined and treated over 10.000 adult and pediatric patients with lacrimal disorders both from the Czech Republic and from abroad.