Reproduced with permission from Optometry Today
Typically, in the UK, lacrimal dilation and irrigation are performed in hospital. However, with a little practice and care, it is a relatively simple procedure for any optometrist or GP to carry out. The equipment required is inexpensive and easily obtained (see Appendices I and II). This paper will review the relevant anatomy and physiology, discuss the aetiology and evaluation of epiphora (watery eye), and then explain dilation, syringing and the various dye tests associated with investigating the lacrimal drainage system. ANATOMY OF THE LACRIMAL DRAINAGE SYSTEM
The anatomy of the complete system is shown diagrammatically in Figure 1. Some important dimensions appear in Figure 2.
One punctum is present at the medial end of both the superior and inferior lid. They are situated on slight elevations called the lacrimal papillae and face posteriorly so it is necessary to evert the medial lids to inspect them. Malposition or stenosis (narrowing) of the puncta may cause epiphora. b) Vertical canaliculus
This is about 2mm long and joins the horizontal canaliculus at a right angle called the ampulla.
c) Horizontal canaliculus
This is about 8mm long and usually joins its fellow to form the common canaliculus which immediately enters the (naso)lacrimal sac through the Valve of Rosenmuller (flap of mucosa to prevent reflux).
d) (Naso)lacrimal sac This is about lOmm long and funnels into the nasolacrimal duct.
e) Nasolacrimal duct This is about l2mm long and opens into the inferior nasal meatus, lateral to the inferior turbinate (concha). The Valve of Hasner closes the opening.
f) Valves About seven other valves have been described within the nasolacrimal duct besides those of Rosenmuller and Horner (see Last) but they have no valvular function and are usually ignored.
PHYSIOLOGY OF THE LACRIMAL DRAINAGE SYSTEM
Capillarity ensures that 70% of the tears enter the inferior canaliculus and 30% through the superior (Figure 3 - pre -blink). On blinking, the attachment of the preseptal orbicularis muscle helps create positive and negative pressure in the lacrimal sac which sucks the tears into it (Figure 3 - during blink). This is called the tear pump. Gravity then helps keep the sac empty (Figure 3 - post-blink).
AETIOLOGY OF EPIPHORA
Epiphora may be due to a hypersecretion of tears as occurs when a foreign body irritates the cornea. Paradoxically, it may also be due to an underlying dry eye problem which, in turn, causes a foreign body reaction and tearing. Likewise, it may be due to a lacrimal pump failure as in ectropion when tears are no longer able to enter the punctum. It may also be caused by punctum plugs or punctum cauterisation for the treatment of dry eye.
EVALUATION OF EPIPHORA
a) General inspection
Inspect the lids to see if they and/or the puncta are poorly positioned. Palpate the lacrimal sac to determine if it is enlarged due to dacryocystitis or a mucocele. Compression may cause a reflux of mucopurulent matter (Figure 4). Pain suggests dacryocystitis.
b) Slit lamp examination
Inspect the puncta for poor position, narrowing or blockage - pouting suggests canaliculitis. A high marginal tear strip may indicate epiphora. If fluorescein is instilled in the conjunctival sac, it should disappear within two minutes - retention suggests there is a problem with lacrimal drainage.
1) Lacrimal dilation
Several types of dilators are available, for example the double-ended stainless steel type in Figure 5 ( see Appendix I) or those incorporated in punctum plug inserters. Their use may effect a cure by releasing mucous plugs or concretions. Dilation may produce temporary relief in a case of stenosis of the punctum. Lacrimal dilation is also used prior to inserting punctum plugs and syringing.
- Wash your hands.
- Some practitioners may wish to put on surgical gloves.
- Instil a drop of anaesthetic on the inferior punctum.
- Sterilise the lacrimal dilator with a Medi-Swab.
- Insert the dilator vertically downwards up to 2mm whilst gently rotating clockwise and anticlockwise (Figure 6).
- Pull the lower lid temporally to straighten the ampulla and line up the vertical and horizontal canaliculi (Figure 7).
- Rotate the dilator horizontally and insert the dilator as required.
As well as irrigating the lacrimal system, syringing may be necessary to dislodge intra- canalicular punctum plugs.
- Wash your hands.
- Some practitioners may wish to put on surgical gloves.
- Dilate the punctum and canaliculus (see under 'lacrimal dilation').
- Open the sterile packets of disposable syringe and cannula and connect them together.
- Remove the plunger and fill the syringe with sterile saline.
- Re-insert the plunger, and with the syringe pointing upward, squeeze out any remaining air together with some saline.
- Insert the cannula into the vertical canaliculus.
- Pull the lower lid temporally to straighten the ampulla and line up the horizontal canaliculus. Rotate the syringe horizontally whilst inserting until a 'hard' or 'soft' stop is felt (see over), then pull back about 2mm (Figure 10).
- Press slowly and gendy on the plunger.
- Ask the patient to report when they taste saline or feel it in their nose.
If the cannula touches the medial wall of the lacrimal sac and lacrimal bone, a definite end point is reached. This is a 'hard stop' (Figure 11) and indicates that there is no complete obstruction in the canalicular system.
If a spongy end point is felt, this is termed a 'soft stop' (Figure 12) and indicates that the cannula has been prevented from entering the lacrimal sac. Therefore, there is a blockage in the canalicular system and there will be no distension of the lacrimal sac when the plunger is pressed.
Detailed diagnosis from lacrimal syringing
- If saline refluxes from the inferior canaliculus, the blockage is there.
- If saline refluxes from the superior canaliculus, the blockage is in the common canaliculus.
- If saline passes into the nose, the problem is hypersecretion of tears or failure of the lacrimal pump or partial obstruction of the nasolacrimal system.
- If saline does not reach the nose, there is a total obstruction of the nasolacrimal duct and saline may appear from the superior punctum - the saline may be purulent if infection is present - and the lacrimal sac may be distended.
- An attempt may be made to close the superior punctum with a dilator or cotton bud and a further effort made to clear the obstruction.
Sometimes, the lacrimal drainage system may appear patent when syringing proceeds uneventfully. However, there may be a functional obstruction. This means that under the low-pressure circumstances of normal tear drainage, all or part of the lacrimal pathway may collapse. Jones dye tests may be used to distinguish between patent systems and functionally blocked ones.
JONES DYE TESTS
PRIMARY AND SECONDARY
- Instil one drop of fluorescein into the conjunctival sac (Figure 13).
- Put a cotton bud soaked in anaesthetic in the inferior meatus.
- If fluorescein is detected after five minutes, the system is patent (positive Primary Jones Test).
- If no fluorescein is discovered, this is a negative Primary Jones Test (Figure 14) and the functional obstruction could be anywhere from the punctum to the Valve of Hasner.
- Next, wash the excess fluorescein from the conjunctival sac and syringe. If fluorescein is detected, then this shows it had entered the sac and constitutes a positive Secondary Jones Test (Figure 15) and suggests a functional obstruction of the nasolacrimal duct.
- If no dye is found on the cotton bud after syringing, this is termed a negative Secondary Jones Test, because fluorescein had not entered the sac and, thus, there is stenosis of the puncta or canalicular system (Figure 16).
- If no saline appears in the nose, there is a complete obstruction somewhere in the lacrimal drainage system.
On the basis of the results obtained from the tests and procedures described above, the patient may leave with their epiphora cured. If not, at least a more informed referral may be made by describing the most likely nature and position of the obstruction.
- Spalton, Hitchings, Hunter (1993) 'Atlas of Clinical Ophthalmology'. 2nd Ed, Mosby Wolfe.
- Kanski (1994) 'Clinical Ophthalmology'. 3rd Ed, Butterworth Heinemam.
- Casser, Fingerat, Woodcome (1997) 'Atlas of Primary Eyecare Procedures'. 2nd Ed, Appleton & Lange.
- Schmidt (1997) 'Lids and Nasolacrimal System'. Butterworth Heinemann.
- Last (1961) 'WoIft's Anatomy of the Eye and Orbit'. 5th Ed. Lewis & Co.
- Lacrimal dilator
- Disposable lacrimal cannulae
- 3 or 5m1 disposable sterile syringes
- Anaesthetic drops, e.g. Ophthaine
- Aerosol bottles of sterile saline
- Disinfection for the dilators, e.g
- Medi- Swabs
- Surgical gloves?
SOME EQUIPMENT SUPPLIERS
John Weiss, 89-90 Alston Drive, Bradwell Abbey, Milton Keynes MK13 9HF
Tel: 01908-318017 Fax: 01908-318708
Castroviejo Lacrimal dilator #0105040 BI 15 Lacrimal cannulae 0108142 7276
Optimed, Alveston House, 11 Broad Street, Pershore Worcs, WR10 1BB
Tel: 01386-561845 Fax: 01386-555177
Irrigating Lacrimal Cannula 260 Code No.1276 Wilders Lacrimal Dilator 13-071