Acquired punctal stenosis is a condition in which the proximal external openings of the nasolacrimal drainage system on the medial eyelid margins are narrower than normal. Stenosis of the puncta may also be accompanied by canalicular stenosis.¹ In contrast to stenosis, punctal agenesis refers to a complete congenital occlusion or absence of the external punctum.

The normal anatomy of the punctum varies greatly.² Common textbook measurements for normal punctal diameter generally range from 0.2 to 0.5 mm.³,⁴,⁵,⁶ However, in formal studies, mean punctal diameters as measured visually, by infrared imaging, or by optical coherence tomography have varied from 0.1 to 0.9 mm.²,⁷,⁸,⁹,¹⁰,¹¹,¹²,¹³,¹⁴ As a result, the concept of what constitutes punctal stenosis is unclear and there does not appear to be any standard definition of a specific size. In the widely used Kashkouli grading system for punctal stenosis,¹⁵ grade 2 is “less than normal size,” grade 3 is “normal regular size,” and grade 4 is “small slit <2 mm” without further definition. Caesar and McNab¹⁶ defined punctal stenosis for their study as a diameter of less than 0.3 mm or the inability to intubate the punctum with a 26 G cannula (outer diameter 0.47 mm) without dilation.

The incidence of punctal stenosis has not yet been studied, but two reports have evaluated the prevalence of the disease. Of 682 patients seen in a hospital-based population, 54.3% had an element of punctal stenosis.¹⁷ Another study showed a prevalence of 17.3% of punctal stenosis among 621 individuals in the general population in Spain.¹⁸ In a study from Turkey on 278 patients 65 years and older, the prevalence of punctal stenosis was 63%, of which 48.9% also had chronic blepharitis, and other associated factors included the use of glaucoma medications and lower eyelid ectropion.¹⁹ However, among 20,102 patients with lacrimal drainage disorders in India, only 3% were diagnosed with punctal stenosis,²⁰ and in a study from Canada of 150 patients with epiphora, 8% were diagnosed with proximal nasolacrimal duct (NLD) (punctal or canalicular) obstruction.

Patients with significant punctal stenosis requiring treatment predominantly have been older women at a mean age of about 65 years.¹,¹⁵,¹⁶,²¹,²²,²³ The most common clinical conditions associated with punctal stenosis include blepharitis, chronic conjunctivitis, meibomian gland dysfunction, and eyelid malpositions.¹,¹⁵,¹⁶,²¹,²²,²³,²⁴ The preponderance of associations with inflammatory conditions and histopathology suggest a common mechanism of chronic inflammation resulting in fibrosis that progressively leads to narrowing of the punctum.²⁵ In several studies, chronic inflammation was found on histopathology of stenotic puncta in 80% to 100% of cases.²³,²⁶,²⁷

Punctal stenosis has also been associated with a very large number of other conditions, although specific etiologic relationships are not always established. These include involutional changes such as aging; inflammatory syndromes such as ocular cicatricial pemphigoid and graft vs host disease; infectious agents such as Chlamydia trachomatis, herpes virus, and actinomyces; topical eye drops and systemic medications such as timolol, latanoprost, betaxolol, chloramphenicol, tobramycin, mitomycin C, 5-fluorouracil, and docetaxel; and local eyelid therapies such as photodynamic therapy.¹⁵,²⁸,²⁹,³⁰,³¹,³²,³³,³⁴ An increased association was also reported with outdoor occupational activities, but not with tobacco and alcohol consumption, or with some systemic diseases such as rosacea, allergy, or diabetes.¹⁸,³⁰

Punctal dysgenesis is a general term used for maldevelopment of the lacrimal punctum. It includes everything from incomplete punctal canalization to true punctal agenesis.³⁵ Familial association has been reported in 36% of cases and a syndromic association in 40%.³⁶

Punctal agenesis was first documented in 1846 by Blanchet and is defined as an absence of the lacrimal punctum secondary to a defect in embryogenesis.³⁷ Although the epithelium of the lacrimal canaliculi makes contact with the conjunctiva in embryos at 9 to 10 weeks of gestation, the puncta remain occluded by a combination of conjunctival and canalicular epithelium until about 7 months of gestation.³⁸ Disruption at any point in this developmental process can lead to punctal dysgenesis.³⁹ One to or both puncta can be involved in one eye, but the condition can also be bilateral.⁴⁰ Epiphora is the most common presenting symptom, and a positive family history was reported in 26% of 50 patients with punctal agenesis.⁴⁰

Incomplete punctal canalization refers to a form of punctal dysgenesis with external and internal punctal membranes.⁴¹,⁴²,⁴³ In the external membrane variant, the membrane covers the external surface of the puncta simulating punctal agenesis. The internal membrane variety has a membrane just at the entrance into the punctum. Both varieties can be misdiagnosed as congenital nasolacrimal duct obstruction in pediatric patients or as punctal agenesis.⁴¹,⁴⁴ Clinical diagnosis is based on the presence of a translucent membrane with slight avascular dimpling at the site of the normal punctum.⁴¹ Occasionally a balloon subtype can be seen with the external membrane variety where the translucent membrane is ballooned upward as a dome that merges with the tarsal conjunctiva.⁴² The pathogenesis of punctal membranes is unknown but is believed to represent either failed dehiscence of the epithelium overlying the normally formed canaliculi or an incomplete canalization of the proximal-most part of the lacrimal drainage system.⁴²