Likely possibilities

1. Surface irritation or corneal problem
   A retained foreign body, corneal abrasion, recurrent erosion, dry eye, eyelash rubbing the eye, or inflammation can cause reflex tearing. These often cause pain, redness, light sensitivity, rubbing, or a foreign-body sensation.
2. Conjunctivitis
   Viral or allergic conjunctivitis is common, especially if there is redness, itching, cold symptoms, or discharge. Bacterial infection usually causes sticky or purulent discharge.
3. Tear-drainage blockage after trauma or surgery
   Injury or scarring of the punctum, canaliculus, lacrimal sac, or nasolacrimal duct can cause tears to overflow onto the cheek. Trauma is a recognized cause of acquired lacrimal obstruction. This is particularly possible if watering is mainly on the previously injured side and there is little pain.
   • The Wills Eye Manual, p. 42
   • Kanski’s Clinical Ophthalmology, lacrimal drainage evaluation section
4. Dacryocystitis, infection of the lacrimal sac
   Suspect this if there is painful redness or swelling at the inner corner of the eye beside the nose, fever, or pus/mucus refluxing from the punctum. It can progress to facial or orbital infection and needs urgent treatment.
   • The Wills Eye Manual, pp. 400-401

Go to an emergency eye service immediately if any of these are present

• Reduced, blurred, or double vision
• Moderate or severe eye pain
• Light sensitivity, inability to keep the eye open
• Red eye with corneal haze or a white spot on the cornea
• Injury again, suspected foreign body, or chemical exposure
• Swelling/redness around the eye, especially near the inner corner
• Fever, pus discharge, headache, vomiting
• Bulging eye, painful/restricted eye movements
• Blood in the eye or an irregular pupil

What the ophthalmologist should assess

• Vision in each eye separately
• Eyelids, lashes, puncta, and position of the lower lid
• Slit-lamp examination with fluorescein staining to look for abrasion, ulcer, leak, or foreign body
• Eye pressure if appropriate
• Examination of the prior surgical wound and internal eye structures
• Lacrimal sac examination for reflux or swelling
• If the eye surface is safe, a fluorescein dye disappearance test and possibly lacrimal probing/irrigation to identify blockage
• CT imaging only if there is suspicion of orbital injury, retained foreign body, infection involving the orbit, or facial fracture

Treatment depends on the cause

• Foreign body/corneal abrasion: removal if present, ophthalmic antibiotic as prescribed, pain control, close review.
• Conjunctivitis/allergy: treatment based on cause. Antibiotic drops are not automatically needed for every watery eye.
• Lacrimal drainage obstruction/scarring: specialist treatment may include probing, irrigation, silicone intubation/stenting, canalicular repair, or later tear-duct surgery depending on where the blockage is.
• Dacryocystitis: urgent systemic antibiotics, and hospital treatment if severe. The drainage obstruction is treated after acute infection settles.

Until examined

• Do not rub the eye or press/massage the inner corner, especially if it is painful or swollen.
• Do not use leftover antibiotic or steroid eye drops. Steroid drops can worsen an undiagnosed corneal infection.
• Use clean water or saline only to gently wipe tears/discharge from the eyelids.
• Avoid patching the eye and avoid contact with dust, play fighting, or swimming.
• Take the prior operative records and list of all current drops/medications to the appointment.