Inflammatory SALDO can include endogenous etiologies like Stevens-Johnson syndrome, cicatricial pemphigoid, sarcoidosis, and Wegener’s granulomatosis (Figs. 13.4 and 13.5). Exogenous etiologies include burns, allergies, use of eye drops like antiviral, radiotherapy, and certain chemotherapeutic agents like 5-fluorouracil and paclitaxel (Figs. 13.6 and 13.7). All the etiologies whether endogenous or exogenous result in response by lacrimal tissues by progressive fibrosis and ultimately result in an obstruction. Instituting measures early on in the inflammatory phase by removing or minimizing the inciting agent, topical and systemic steroids, and recanalization procedures in later phases help in reducing the morbidity associated with epiphora.

Traumatic SALDO is a distinct entity that includes iatrogenic and accidental trauma. Iatrogenic etiologies include probing, intubation, punctal plugs, and sinus surgeries (Figs. 13.8 and 13.9). Accidental traumas involve SALDO secondary to either a soft tissue trauma or a bony trauma. Among the soft tissue injuries, canalicular tears are the most common (Figs. 13.10 and 13.11), and among the bony injuries, specific naso-orbito-ethmoid fractures are known to cause nasolacrimal entrapment and damage (Figs. 13.12 and 13.13) [23]. The specifics of diagnosis and treatment are mentioned in detail in the Chap.​ 16.

The term mechanical refers to a lacrimal passage physically obstructed anywhere along its entire course by specific agents. These could be endogenous factors like dacryoliths (Fig. 13.14) and migrated punctal plugs or exogenous factors like conjunctivochalasis (Fig. 13.15), sinus mucocele (Fig. 13.16), or caruncular masses (Fig. 13.17). Treatment consists of removing the inciting agent like punctal plugs and excision of caruncular mass or redundant conjunctiva.