Congenital nasolacrimal duct obstruction (CNLDO) is a condition in which the caudal opening of the nasolacrimal duct fails to open into the inferior meatus congenitally. It occurs in 6–20% of newborns and is the most common lacrimal disorder in children. 1)
At the lower end of the nasolacrimal duct, a membranous structure formed by the fusion of the nasolacrimal duct epithelium and nasal mucosa is observed around the 13th week of gestation. This membrane begins to disappear around the 32nd week, opening the nasolacrimal duct into the nasal cavity, but it persists in about 20% of cases even at the 38th week, just before birth. The persistence of this membrane is called congenital nasolacrimal duct obstruction. This membrane often disappears spontaneously after birth, and the nasolacrimal duct usually opens naturally; the lacrimal drainage system in newborns is considered to be still developing.
Approximately 80% of cases are unilateral, and no gender difference or clear genetic predisposition has been identified. 1)
The spontaneous resolution rate is high: about 60% resolve by 3 months of age, and about 90% by 12 months of age. A prospective study reported a spontaneous resolution rate of 96% by 12 months of age. 4) The spontaneous resolution rate within the first year of life is reported to be 89–96%. 1)
About 90% of cases resolve spontaneously by 12 months of age. Properly performed lacrimal sac massage (Crigler method) may promote resolution. 4) If symptoms persist beyond 1 year of age, interventions such as probing are considered.
The main symptoms are tearing and discharge, which appear early after birth.
The most common cause of CNLDO is membranous obstruction due to delayed regression of the valve of Hasner. Other causes include bony obstruction (narrowing of the entire nasolacrimal duct or bony canal) and congenital proximal lacrimal drainage system anomalies (underdevelopment of the punctum and canaliculus).
Risk factors for CNLDO are as follows:
Among severe CNLDO cases, complete obstruction 35%, punctal agenesis 15%, congenital fistula 10%, and craniofacial bone defects 5% have been reported. 1)
In Down syndrome, CNLDO occurs in up to 30% of cases, which is more frequent than in the general newborn population (6–20%). 1) This is thought to be related to associated craniofacial structural abnormalities.
The diagnosis of CNLDO is made through history taking, visual inspection, palpation, dye disappearance test, and lacrimal irrigation test.
Fluorescein dye disappearance test (FDDT): Moisten a fluorescein ophthalmic test strip with saline, apply it to the lower palpebral conjunctiva, and wait about 15 minutes without rubbing the eyes. Observe the ocular surface under blue light in a dark room; residual dye indicates impaired tear drainage. If fluorescent dye reaches the nasal discharge, the lacrimal passage is patent, ruling out congenital nasolacrimal duct obstruction. 4) Sensitivity is reported as 90% and specificity as 100%. 1)
Lacrimal irrigation test: This is useful for confirming lacrimal duct obstruction, but in children, immobilization is required to control body movement. It is an invasive procedure performed by wrapping the child in a bath towel and fixing the head. 4) In congenital nasolacrimal duct obstruction, reflux containing pus is observed during irrigation.
CT scan: Performed when bony obstruction is suspected.
| Test | Characteristics |
|---|---|
| Fluorescein dye disappearance test (FDDT) | Sensitivity 90%, specificity 100% |
| Lacrimal irrigation test | Confirms obstruction. Invasive. Children require immobilization. |
| CT | Evaluation of bony obstruction |
The following diseases must be differentiated. 4)
This is a technique in which a finger is placed on the lacrimal sac area and pressure is applied to push the contents of the lacrimal sac toward the lower end of the nasolacrimal duct, avoiding expulsion through the punctum. Perform 5 to 10 compressions per set, 2 to 4 sets per day. Simple massage (lightly pressing the lacrimal sac area) does not improve the cure rate. 4)
The guideline recommendation is CQ1: “Weakly recommend performing” (strength of evidence C). 4)
Results of major RCTs:
Existing data report a success rate of 85% or higher. 1) There are no reports of obvious adverse effects, but there have been cases of lacrimal sac rupture leading to cellulitis due to massage. It may be difficult for caregivers to perform correctly.
When there is a large amount of discharge, use tosufloxacin 0.3%. In guideline CQ2, it is “weakly recommended to perform” (strength of evidence C), but there are important points to note. 4)
The age-specific indications for probing are as follows.
In guideline CQ3, for unilateral cases, it is weakly recommended to perform probing under local anesthesia at around 6 to 9 months of age (strength of evidence C). For bilateral cases, no recommendation could be made. 4)
PEDIG RCT results: In 163 unilateral cases, immediate probing group 92% (69 of 75 eyes) vs. delayed probing group 82% (58 of 71 eyes). No significant difference. Spontaneous resolution during the waiting period was 66% (44 of 67 eyes). 4)
Age-specific probing success rates (meta-analysis, 17 studies, 7110 eyes): 3)
| Age | Success rate |
|---|---|
| 0–6 months | 90.67% |
| 6–12 months | 85.18% |
| 12–24 months | 82.34% |
| 24–48 months | 85.33% |
| Over 48 months | 63.47% |
Probing technique: Performed under topical anesthesia (lidocaine). The child is wrapped tightly in a large towel, and a strong nurse straddles and fixes the shoulders, jaw, and head (do not press the head too hard). Insertion of the bougie via the upper lacrimal punctum is advantageous, as there is no resistance before the lacrimal sac (ampulla or sharp bend) and the risk of damaging the lacrimal canaliculus is low. The nasolacrimal duct can be advanced without resistance to the distal obstruction, and the resistance upon perforating the obstruction ranges from a light membranous resistance to a relatively firm one. Postoperatively, antibiotic eye drops and oral antibiotics are prescribed. Since this is a contaminated procedure, systemic infections such as sepsis may rarely occur; therefore, pay close attention to fever on the day of the procedure.
Probing complications: Bleeding reflux from the punctum occurs in about 20% of cases during probing. 4) Rare complications such as bacteremia, meningitis, hip arthritis, and endocarditis have been reported. 1)
Lacrimal endoscopy is a technique that allows visualization of the lacrimal duct lumen and opening of the obstruction under direct vision. In guideline CQ4, it is recommended as a weak recommendation (evidence level C). 4)
Repeat blind probing is not recommended (Guideline CQ5: “Weak recommendation against performing”, strength of evidence C). 4)
The cure rate of repeat blind probing varies widely: prospective studies 53% and 25%, retrospective studies 61–85.7%. In the Honavar prospective cohort, the rate decreased from 73.3% at first attempt to 25.0% at second attempt. 4)
Lacrimal tube insertion vs. repeat blind probing: Lacrimal tube insertion group 92% vs. repeat probing group 67% (retrospective study, significant difference). The cure rate of lacrimal tube insertion (stenting) in 7 studies is 75–100%. 4)
Lacrimal tube insertion (stenting): Mainly indicated for probing failure. Success rate for initial placement is 90–96%, after probing failure approximately 84%. 1) In Japan, the nunchaku-type tube is mainstream (different shape from the Crawford tube used overseas). Tube complications (most commonly dislocation/self-removal) are reported in 0–31% of cases. 4)
Balloon dilation: Success rates are reported as 53–95%, but no clear superiority over probing has been demonstrated.
DCR is a radical surgery for nasolacrimal duct obstruction. It is indicated when the above treatments are ineffective or in cases of bony obstruction. Since it involves invasion of the periosteum, it is generally recommended after around age 15 when facial bone growth is complete, but in severe cases early surgery may be necessary.
Success rate of external DCR is 96%, and endoscopic DCR is 82–94%. 1) The endonasal approach has the advantages of no facial scar and less bone resection, but requires skilled technique. Postoperative stenting is performed for 8–12 weeks.
Conservative Treatment
Lacrimal sac massage (Crigler method): 5–10 strokes per set, 2–4 sets per day. 4)
Antibiotic eye drops: Use only when necessary. Be aware of the risk of resistant bacteria. 4)
Indication: First-line treatment up to 6 months of age.
Probing
Timing: For unilateral cases, around 6–9 months of age is suggested. 4)
Procedure: The membrane is perforated with a probe through the upper lacrimal canaliculus.
Success rate: 63–91% depending on age. 3)
Endoscopy, Tube, DCR
Lacrimal endoscopy: Curved type 92.3–100%. 4) Recommended for unsuccessful cases.
Lacrimal tube: Tube insertion 75–100%. 4)
DCR: Curative surgery. External approach 96%. 1)
Guidelines weakly suggest performing probing under local anesthesia around 6–9 months of age for unilateral cases. 4) For bilateral cases, it was deemed inconclusive. The PEDIG RCT found no significant difference between immediate probing and delayed probing groups. Considering the possibility of spontaneous resolution, a strategy of prioritizing conservative management until 12 months of age is also an option.
Repeat blind probing is not recommended (Guideline CQ5). Probing using a dacryoendoscope (curved type, success rate 92.3–100%) or lacrimal tube intubation (75–100%) is suggested. 4) If these are ineffective, dacryocystorhinostomy (DCR) is considered as a curative treatment.
The Crigler method is recommended. Place a clean finger over the lacrimal sac area (medial to the inner canthus, at the root of the nose) and apply pressure in the direction toward the lower end of the nasolacrimal duct (inferiorly) to avoid reflux of sac contents toward the eye. Perform 5–10 compressions per set, 2–4 sets per day. 4) Simple massage by lightly pressing the lacrimal sac area is less effective. If the skin becomes red or painful, stop and consult a doctor.
Development of the lacrimal drainage system begins at 3–5 weeks of gestation. The lacrimal groove forms from the surface ectoderm, and canalization progresses around the third month of gestation. 1) The most distal part of the nasolacrimal duct (Hasner’s valve) opens last, usually completing by the eighth month of gestation.
At the 13th week of gestation, a membranous structure formed by fusion of the nasolacrimal duct epithelium and nasal mucosa is observed. Around the 32nd week, this membrane disappears and the nasolacrimal duct opens into the nasal cavity, but it remains in about 20% of cases even at the 38th week just before birth. This residual membrane is the condition of congenital nasolacrimal duct obstruction, which often resolves spontaneously after birth, so the neonatal lacrimal drainage system is considered to be still developing.
The anatomy of the lacrimal drainage system is as follows:
Sites and types of obstruction:
A relatively rare condition in which acute dacryocystitis occurs secondary to congenital nasolacrimal duct obstruction. Inflammation is treated with topical and oral antibiotics, and intravenous antibiotics in severe cases. After inflammation subsides, prompt probing is performed due to the risk of recurrence, skin fistulization, or cellulitis. Common causative organisms are Staphylococcus aureus and Haemophilus influenzae.
A relatively rare congenital anomaly characterized by a distinctive dark-bluish mass-like elevation inferomedial to the inner canthus. It may be complicated by dacryocystitis or cellulitis. Cases with large intranasal cysts or bilateral involvement may cause respiratory distress.
Data from Guideline CQ7: 4)
It is considered inconclusive whether congenital nasolacrimal duct obstruction is a cause of amblyopia (strength of evidence D), but general examination within the feasible range is strongly recommended. 4) In a Japanese report, 13% of 94 cases of unilateral congenital nasolacrimal duct obstruction had refractive errors corresponding to amblyopia risk. Some reports indicate that about 5% have amblyopia. 1)
Sultanbayeva et al. (2025) conducted a meta-analysis of 17 studies and 7110 eyes to examine probing success rates by age group. 3) The overall success rate was 90.67% at 0–6 months (95.42% under general anesthesia, 88.82% under local anesthesia), 85.18% at 6–12 months, 82.34% at 12–24 months, and decreased to 63.47% at >48 months. The certainty of evidence was judged low for all subgroups.
A meta-analysis of 4 RCTs (423 patients) by Farat et al. (2021) found no significant difference in resolution rates between early and late probing (RR 1.00; p=0.99). 2) Meanwhile, the PEDIG study showed that early probing was more cost-effective ($562 vs $701).
Endoscopy-assisted probing is being considered as an alternative to conventional blind probing. 1) The use of a lacrimal endoscope allows direct visualization of the obstruction site, potentially reducing the risk of iatrogenic injury and improving success rates. Facilities capable of performing this procedure in children are currently extremely limited, and its future dissemination remains a challenge. 4)
Application of mitomycin C to the anastomosis site is being investigated to improve the success rate of endoscopic DCR. 1) It is expected to prevent granulation and scar formation, but long-term safety requires further data accumulation.
