Causes of acquired obstruction

Question 1

What are the causes of acquired obstruction?

Answer 1

Primary punctal stenosis
Secondary punctal stenosis
Canalicular obstruction
Nasolacrimal duct obstruction
Dacrolithiasis

Question 2

What are the causes of primary stenosis in order of frequency?

Answer 2

Associated with chronic blepharitis
Idiopathic primary stenosis
Herpes simplex or herpes zoster infection of the lid
After irradiation of malignant tumors
Systemic cytotoxic drugs e.g. 5 Flurouracil or docetaxel
Rare systemic disorder e.g. Porphyria cutanea tarda or acrodermatitis enteropathica

Question 3

What is the treatment of primary punctal stenosis?

Answer 3

Dilatation of the punctum - rarely gives long term benefit

Punctoplasty - Enlargement of the ampulla via 2 or 3 snip procedure

Question 4

What is the cause and treatment of secondary punctal stenosis?

Answer 4

Caused by punctal eversion

Treatment:-

For pure eversion can do Ziegler cautery - cauterise tarsal conjunctiva 5mm below the punctum. The subsequent shrinkage of the tissue (cicatrization) causes inversion of the punctum

Medial conjunctivoplasty - can be done in medial ectropion not associated with lid laxity. A diamond shaped piece of tarsal conjunctiva is removed measuring 4mm in height and 8mm in width. Should be parallel and infero-lateral to the canaliculus and punctum. This is followed by approximation of the upper and lower margins and incorporation of the lower lid retratctors further aids inverstion of the punctum. Punctoplasty should then follow or dilatation so the puncutm remains open once normal tear flow is established.

Lower lid tightening - lateral tarsal sling to to correct lower lid laxity and can combine with medial conjunctivoplasty if medial ectropion component present

Question 5

What are the causes of canalicular obstruction

Answer 5

Congential
Trauma
Herpes simplex infection
Irradiation
Chronic dacrocystitis can cause a thin membrane to form in the common canaliculus

Question 6

How is it treated

Answer 6

Partial - obstruction of individual or common canalicular or indeed any part of the nasolacrimal drainage system can be treated with silicone stents through one or both canalicular and left in situ for 3-6 months

Total individual canalicular obstruction with 6-8mm of patent normal canaliculus between the punctum and obstruction can be treated with a canaliculadacrocystorhinostomy (CDCR) treated by anastomosis of patent part of canaliculus to lacrimal sac. Where this cannot be done then a conjunctivodacrocystorhinostomy is done and a special tube (lester jones) is inserted