The punctum is an opening approximately 0.5 mm in diameter, located at the inner canthus of each upper and lower eyelid. It serves as the entrance to the tear drainage system and functions as the starting point of the “tear pump” that drains tears through the canaliculi, lacrimal sac, and nasolacrimal duct into the nasal cavity. When this opening becomes narrowed (stenosis) or completely closed (occlusion), tears accumulate in the conjunctival sac, causing epiphora.
Punctal stenosis/occlusion is broadly classified into congenital and acquired types based on the mechanism and cause. Congenital cases result from incomplete formation of the punctum during embryonic development. Acquired cases arise from various causes such as inflammation, scarring, medications, aging, and trauma.
When the obstruction is limited to the punctum alone, it is called punctal occlusion; even if the canaliculi are patent, tear inflow is blocked at the punctum. This condition differs from downstream obstructions such as nasolacrimal duct obstruction, and differentiation is important (see Diagnosis and Examination Methods for details).
The classification of occlusion types is shown below.
| Type | Main Causes |
|---|---|
| Congenital punctal agenesis | Embryonic punctal malformation (opens at 6 months of gestation) |
| Inflammatory or cicatricial occlusion | Stevens-Johnson syndrome, ocular pemphigoid, chronic inflammation |
| Drug-induced occlusion | Glaucoma eye drops, S-1 (TS-1®), IDU |
| Age-related or idiopathic stenosis | Age-related punctal narrowing |
| Traumatic | Scarring after burns or chemical corrosion |
Punctal stenosis is a narrowing of the entrance of the tear drainage pathway (the punctum), while nasolacrimal duct obstruction is an obstruction of the exit side (the nasolacrimal duct). Both cause epiphora, but punctal stenosis is diagnosed by direct observation of the punctum with a slit lamp, and nasolacrimal duct obstruction is diagnosed by confirming passage obstruction through lacrimal irrigation. Whether the punctum is patent is the first point of differentiation.
The main symptom of punctal stenosis or occlusion is persistent epiphora.
Note: In cases complicated by aqueous-deficient dry eye, punctal occlusion may stabilize the tear meniscus on the ocular surface, making epiphora less noticeable. In such cases, the diagnosis of punctal occlusion can be easily overlooked, so caution is needed.
The punctum opens at the 6th month of gestation and is patent to the inferior meatus at birth. Disruption of this process leads to congenital punctal agenesis. It presents as absence of one or more puncta in the upper and lower eyelids, with various patterns of deficiency. Other parts of the lacrimal drainage system are often normally developed.
Causes of acquired punctal occlusion are classified as inflammatory, drug-induced, age-related, and traumatic. Chronic blepharitis is the most common cause reported in the literature, accounting for 45% in one prospective study (Kashkouli et al., 2003 PMID: 14644218). For a comprehensive review of epidemiology and etiology, see Tawfik & Ali, 2024 PMID: 38336342.
Inflammatory/Cicatricial
Stevens-Johnson syndrome: Severe ocular surface inflammation in the acute phase can lead to scarring around the punctum, resulting in punctal occlusion. Ocular cicatricial pemphigoid similarly progresses from chronic inflammation to scarring.
Chronic ocular surface inflammation: Long-standing chronic allergic conjunctivitis or infectious conjunctivitis can also lead to fibrosis around the punctum.
Drug-induced
Glaucoma eye drops: Timolol, dorzolamide, pilocarpine, etc. are considered risk factors for upper lacrimal duct obstruction. Long-term instillation causes chronic inflammation of the lacrimal duct epithelium.
S-1 (TS-1®): Punctal and canalicular obstruction during anticancer treatment often becomes severe, and early tube insertion is recommended.
IDU (antiviral drug): Eye drops used for topical treatment of herpetic eye disease (iododeoxyuridine) are also a risk factor for upper lacrimal duct obstruction.
Age-related and traumatic
Age-related/idiopathic stenosis: The punctum may shrink with age, leading to idiopathic stenosis. This is mainly a narrowing of the opening rather than obstruction, and it often improves with dilation procedures.
Traumatic: Scar formation after burns or chemical corrosion can close the punctum. Depending on the extent of injury, complete obstruction may occur.
Lacrimal duct disorder caused by S-1 (a combination drug of tegafur, gimeracil, and oteracil potassium) occurs because its metabolite (5-fluorouracil; 5-FU) is secreted into the tear fluid. 5-FU directly stimulates the lacrimal duct epithelium chemically, leading to local inflammation → fibrosis → scar formation. It is thought to progress depending on the dose and duration of administration, and early intervention is important.
Glaucoma eye drops such as timolol, dorzolamide, and pilocarpine are considered risk factors for upper lacrimal duct obstruction. Long-term use can cause chronic inflammation of the lacrimal duct epithelium, leading to fibrous stenosis of the punctum. If tearing symptoms appear during long-term use, it is recommended to undergo slit-lamp microscopic examination of the punctum.
The metabolite of S-1 (5-FU) is secreted into the tear fluid, causing chemical irritation to the lacrimal duct epithelium, leading to inflammation and scar formation. Since it tends to become severe, it is recommended to see an ophthalmologist early when tearing appears and to consider the appropriateness of lacrimal tube insertion. While continuing anticancer drug use, it is desirable to keep the tube in place and follow up.
Diagnosis of punctal stenosis or obstruction begins with direct observation of the punctum itself using a slit-lamp microscope. After confirming the patency and morphology of the punctum, lacrimal irrigation is performed to evaluate the patency of the canaliculi and beyond.
Epiphora has various causes, and differentiation from diseases other than punctal stenosis or obstruction is necessary.
| Differential Diagnosis | Key Points for Differentiation |
|---|---|
| Excessive tear secretion (reflex tearing) | Caused by conjunctivitis or keratitis. Punctum is normal. Schirmer test normal to high. |
| Canalicular obstruction | Punctum is patent but irrigation shows obstruction. |
| Nasolacrimal duct obstruction | Punctum is patent but irrigation shows obstruction. May be accompanied by lacrimal sac swelling. |
| Dry eye | Decreased tear secretion → reflex tearing. Low Schirmer test value. Shortened tear break-up time. |
If the punctum is clearly patent on slit-lamp examination but tearing persists, consider downstream obstruction of the lacrimal drainage system (canalicular or nasolacrimal duct obstruction) or reflex tearing due to dry eye.
For acquired punctal stenosis or obstruction, a stepwise approach is used.
Step 1: Punctal dilation or incision
Procedure: Under topical anesthesia, the punctum is incised and dilated using a punctal dilator or a sharp blade (fine scalpel).
Indications: First-line treatment for acquired punctal stenosis or obstruction. Particularly effective for membranous occlusion.
Note: The procedure can be performed in an outpatient setting in a short time.
Step 2: Punctal Plug Insertion
Procedure: To prevent re-occlusion after dilation, a punctal plug is inserted for 2–4 weeks and then removed.
Purpose: To maintain the dilated punctum open and prevent restenosis due to scarring.
Plug selection: Measure the punctal diameter with a punctal gauge and select the appropriate size.
Step 3: Silicone Tube Insertion
Indication: Cases with re-occlusion after Step 1.
Procedure: After re-incising the punctum, insert and place a silicone tube in the canaliculus. Remove after 1–2 months.
Purpose: The tube physically maintains the punctal opening and suppresses scar formation.
The activity of the underlying inflammatory disease is important in treatment selection; re-occlusion rates are high in active stages of Stevens-Johnson syndrome and ocular pemphigoid. Concurrent control of inflammation in the underlying disease improves treatment outcomes.
In congenital punctal occlusion or agenesis, treatment varies depending on the pattern of deficiency.
If punctal or canalicular occlusion occurs during S-1 administration, early tube insertion is recommended because it tends to become severe. Since re-occlusion is likely if the tube is removed while continuing anticancer drug use, it is desirable to maintain tube placement during the S-1 administration period.
| Technique/Method | Description | Main Indications |
|---|---|---|
| Punctal dilation/incision | Under topical anesthesia, using a punctal dilator or sharp blade | First choice for acquired punctal stenosis |
| Punctal plug placement (2–4 weeks) | Prevention of re-occlusion after dilation | Maintenance therapy after punctal incision |
| Canalicular silicone tube (1–2 months) | Placement in the canaliculus followed by removal | Cases of re-occlusion |
| Bougie/punctal incision | Lacrimal duct dilation | Congenital membranous occlusion |
| CDCR (conjunctivodacryocystorhinostomy) | Creation of drainage pathway using a glass tube | Congenital absence of all puncta |
Reocclusion after punctal dilation or incision can occur. The reocclusion rate is particularly high during the active phase of inflammatory diseases such as Stevens-Johnson syndrome and ocular pemphigoid. In cases of reocclusion, silicone tube intubation is performed to maintain punctal patency for 1 to 2 months. Controlling the activity of the underlying disease is important to prevent reocclusion.
The punctum is located on the eyelid margin approximately 6 mm from the inner canthus of the upper and lower eyelids. An opening about 0.5 mm in diameter exists on a papillary elevation (lacrimal papilla) and leads to the canaliculus. The contraction of the orbicularis oculi muscle during blinking provides a “tear pump” function that draws tears from the punctum. When the punctum is obstructed, this pump function is lost, and tears accumulate in the conjunctival sac, causing epiphora.
The common pathogenesis of acquired punctal obstruction is “inflammation → fibrosis → scar formation.”
When inflammation occurs around the punctum, inflammatory cytokines and growth factors activate fibroblasts, leading to increased collagen production. The submucosal tissue of the punctal opening is replaced by fibrous tissue, causing the opening to gradually narrow and close. In Stevens-Johnson syndrome, severe acute inflammation forms irreversible scars in a short period, while in ocular pemphigoid, chronic inflammation due to autoimmune mechanisms progresses slowly. In both cases, reocclusion after treatment is likely during the active phase of the underlying disease.
Tegafur, the main component of S-1, is converted to 5-FU in the body. 5-FU is secreted into tears and exhibits direct cytotoxicity to lacrimal duct epithelial cells. Scarring occlusion of the punctum and canaliculus progresses through the pathway of epithelial damage → inflammation → submucosal fibrosis. There is a correlation between dose/duration and severity of occlusion, with higher risk for long-term, high-dose administration (Esmaeli et al., 2005 PMID: 16086962; Kim et al., 2012 PMID: 22589332). In a prospective study of gastric cancer patients by Kim et al., 18% developed epiphora during S-1 administration, and 88% of those were found to have lacrimal duct obstruction.
The lacrimal drainage system is formed during the embryonic period by invagination and canalization of the ectoderm. The punctum opens around the 6th month of gestation, and the lacrimal drainage system connecting to the inferior meatus is completed at birth. If this canalization and opening process is impaired, congenital punctal agenesis occurs. There are two types: complete absence of the lacrimal drainage system (severe agenesis) and cases where the system is formed but the entrance is closed by a membrane (membranous closure); the latter has a good treatment outcome.
Although established procedures exist for the treatment of punctal stenosis and obstruction, research is ongoing in several areas.
Comparison of punctal dilation techniques: Comparisons of one-snip (single incision of the posterior punctum), two-snip (two incisions of the posterior punctum and horizontal canaliculus), and three-snip punctoplasty have been reported, with ongoing investigation of differences in restenosis rates and complications. Murdock et al. (2015) reported a symptom improvement rate of 86% with primary three-snip punctoplasty (PMID: 25906237). For the latest treatment outcomes and complications review, see Tawfik & Ali Part II (PMID: 38796110). Establishing the optimal incision range and restenosis prevention method remains a future challenge.
Preventive intervention for S-1-related lacrimal duct obstruction: Strategies such as prophylactic silicone tube insertion before starting S-1 administration and the usefulness of regular punctum evaluation protocols after administration are being studied. Data on the incidence of lacrimal duct obstruction and its dose- and duration-dependence are being accumulated.
Materials and long-term outcomes of punctal plugs: Comparative studies are being conducted on the long-term retention, spontaneous loss rate, and risk of migration of silicone-based plugs (Super Eagle™ plug, Punctal Plug® F) and atelocollagen-based plugs (Keeptear®).
Long-term outcomes of surgical punctal occlusion (for dry eye treatment): Studies continue on the long-term recanalization rate and optimal technique for intentional punctal occlusion (permanent closure by electrocautery or suturing) performed as a treatment for dry eye.
