Diagnostics

Question 1

Fluorescein disappearance test - normal marginal tear strip

Answer 1

0.2–0.4 mm

Question 2

Fluorescein disappearance test - high marginal tear strip

Answer 2

0.6 mm or more

Question 3

Fluorescein disappearance test - positive

Answer 3

little or no dye remains after 5–10 minutes

Question 4

‘fluorescein clearance test’ - for what and how

Answer 4

to assess tear turnover in dry eye, in which retained stain is measured in the meniscus 15 minutes after instillation of 5 μl of fluorescein

Question 5

Lacrimal irrigation - when contraindicated

Answer 5

acute infection

Question 6

Lacrimal irrigation - when can you do this

Answer 6

Lacrimal irrigation should be performed only after ascertaining punctal patency; if absent or severely stenosed, surgical enlargement of the punctum may be needed before canalicular and nasolacrimal duct patency can be confirmed

Question 7

Lacrimal irrigation - instrumentation

Answer 7

gently curved, blunt-tipped 26- or 27-gauge lacrimal cannula on a 3 ml saline-filled syringe

Question 8

Lacrimal irrigation - hard stop

Answer 8

occurs if the cannula enters the lacrimal sac, coming to a stop at the medial wall of the sac, through which can be felt the rigid lacrimal bone. This excludes complete obstruction of the canalicular system

Question 9

Lacrimal irrigation - soft stop

Answer 9

if the cannula stops at or proximal to the junction of the common canaliculus and the lacrimal sac. In the case of lower canalicular obstruction, a soft stop will be associated with reflux of saline through the lower punctum. Reflux through the upper punctum indicates patency of both upper and lower canaliculi, but obstruction of the common canaliculus

Question 10

Jones dye testing - when to perform

Answer 10

only in patients with suspected partial obstruction of the drainage system. Epiphora is present, but there is no punctal abnormality and the patient tastes saline in his or her throat on irrigation

Question 11

primary test Jones dye testing - for what and how to perform

Answer 11

differentiates partial obstruction of the lacrimal passages and lacrimal pump failure from primary hypersecretion of tears. A drop of 2% fluorescein is instilled into the conjunctival sac of one eye only. After about 5 minutes, a cotton-tipped bud moistened in local anaesthetic is inserted under the inferior turbinate at the nasolacrimal duct opening

Question 12

Positive primary test Jones dye testing

Answer 12

fluorescein recovered from the nose indicates patency of the drainage system. Watering is due to primary hypersecretion and no further tests are necessary

Question 13

Negative primary test Jones dye testing

Answer 13

no dye recovered from the nose indicates a partial obstruction (site unknown) or failure of the lacrimal pump mechanism. In this situation the secondary dye test is performed immediately. There is a high false-negative rate – that is, dye is commonly not recovered even in the presence of a functionally patent drainage system

Question 14

secondary test Jones dye testing - for what and how to perform

Answer 14

identifies lacrimal pump failure or the probable site of partial obstruction. Topical anaesthetic is instilled and any residual fluorescein washed out from the conjunctival fornix. The drainage system is then irrigated with a cotton bud under the inferior turbinate

Question 15

Positive secondary test Jones dye testing

Answer 15

fluorescein-stained saline recovered from the nose indicates that fluorescein entered the lacrimal sac, thus confirming functional patency of the upper lacrimal passages. Partial obstruction of the nasolacrimal duct distal to the sac is inferred

Question 16

Negative secondary test Jones dye testing

Answer 16

unstained saline recovered from the nose indicates that fluorescein did not enter the lacrimal sac. This implies upper lacrimal (punctal or canalicular) dysfunction, which may be due to partial physical occlusion and/or pump failure

Question 17

Contrast dacryocystography - how to perform

Answer 17

injection of radio-opaque contrast medium (ethiodized oil) into the canaliculi followed by the capture of magnified images

Question 18

Contrast dacryocystography - indications

Answer 18

confirmation of the precise site of lacrimal drainage obstruction to guide surgery, and the diagnosis of diverticuli (uchyłki), fistulae and filling defects (e.g. stones, tumours)

Question 19

Contrast dacryocystography - when not to do

Answer 19

No in acute infection

Question 20

Contrast dacryocystography - when normal

Answer 20

in the presence of subjective and objective epiphora suggests failure of the lacrimal pump

Question 21

Nuclear lacrimal scintigraphy - how and for what

Answer 21

labelling the tears with a radioactive substance and tracking their progress. Although it does not provide the same detailed anatomical visualization as DCG, it may be used to identify the location of a partial or functional block (e.g. indicating the absence of significant tear entry to the canaliculi, localizing the site of physiological obstruction to the eyelids), to confirm functional obstruction

Question 22

CT and MRI - when

Answer 22

in the investigation of paranasal sinus or suspected lacrimal sac pathology

Question 23

Internal nasal examination -

Answer 23

especially with endoscopy, detection of obstructions such as nasal polyps or a deviated septum