Emergency ophthalmic procedures
Retrobulbar hemorrhage (canthotomy and cantholysis guidelines)
- Everting upper lid
- Instillation of eye drops/ Common eye drops and indications
- Seidels test (to detect corneal perforation)
- Eye shield application (globe rupture)
1. Retrobulbar haemorrhage
This may occur after a blunt injury to the eye or following head trauma or orbital fracture and is shown on imaging but may be diagnosed with sudden onset retro-orbital pain, loss vision and injection of the eye. Blood collects behind the eye in the retrobulbar space and can cause an orbital compartment syndrome, Blood trapped in this space puts compresses the optic nerve, globe and retina causing ischaemia. This orbital compartment syndrome is an ophthalmic emergency. Non-perfused retina infarcts irreversibly in around 90 mins and delay may lead to permanent vision loss. An emergency canthotomy/cantholysis is required.
This must be performed as soon as the condition is detected and there is often no time to refer to another oncall ophthalmology centre if it occurs out of hours. If it occurs in hours please call the Emergency Eye Clinic immediately on 01708 435 000 Ext 6662
These are two procedures performed alongside each other to save sight in the context of ocular compartment syndrome aka retrobulbar haemorrhage. The lower eyelid is released from its periosteal attachment to release the trapped blood that has collected in the retrobulbar space.
A canthotomy is a cut to the lateral canthus (around 1 cm full thickness) see fig 3 This alone provides very little soft tissue decompression but is performed in order to gain access to the lateral canthal tendon so a cantholysis may be performed to release the lower lid from its periosteal attachments see fig 4.
Figure 3: Canthotomy
Figure 4: Cantholysis
The procedure may be performed in A+E and needs basic equipment only.
- Anaesthetic eye drops e.g tetracaine or proxymetacaine 0.5%
- Povidoiodine for cleaning
- 25G orange needle for local subcutaneous anaesthetic injection
- 5-10ml Syringe
- Lignocaine 2% with adrenaline
- Blunt tipped scissors (e.g Westcott or Stevens)
- Toothed forcepts (e.g Bishop Harmon or Adson)
- Instill anaesthetic eye drops to both eyes. (The other eye may start to tear if it is open and exposed for a long time which will cause the patient to blink and squeeze and may cause them to close the affected eye.)
- Gently clean the periorbital skin.
- Instill subcutaneous lignocaine 2% with adrenaline to the lateral skin around the eye (inject with the needle bevel away from the eye).
- Perform the canthotomy: place the scissors across the lateral canthus and cut full thickness for around 1 cm. See figure 3
- Perform the inferior cantholysis: Hold the lower eyelid with the forceps in your non dominant hand and insert scissor blades around the canthal tendon, pointing the tip of the blades more towards the patients nose and cut the tendon. The procedure is deem successful once the lower eyelid may then be lifted completely freely away from its bony connection, you see a rush of released blood or the patient reports an improvement in vision. See figure 4
- If there is bleeding, apply pressure on the orbital rim (not the globe) for several minutes.
- The patient will need a full examination by an ophthalmologist and intraocular pressure monitoring. The vision should be monitored regularly.
Tetanus Prophylaxis: Table 1
|History of tetanus Immunisation (doses)||Clean minor wounds||Clean minor wounds||All other wounds||All other wounds|
|Tetanus Toxoid*||Immune globulin||Tetanus Toxoid||Immune globulin|
|Uncertain or fewer than 2 doses||Yes||No||Yes||Yes|
- *Dose of tetanus toxoid is 0.5 ml IM
- aUnless wound is >24 hours old
- bUnless >10 years since last dose
- cUnless > 5 years since last dose
2. Everting eyelids:
This is useful to assess if any foreign bodies are trapped under the eyelids. Ask the patient to look down and place a cotton bud across the central part of the upper lid crease to act as a pivot. Gently hold onto the upper eyelashes with the other hand and pull them up so the lid is folded over the cotton bud causing the upper lid to evert (See Fig 5.1, 3.)
Figure 5: Everting the upper lid
3. Instillation of eye drops:
Ask the patient to look up, gently pull down their lower eyelid exposing the lower conjunctival sac and pipet the drop into the pocket formed.
Common Eye Drops and indications:
Proxymetacaine 0.5%, tetracaine. Warn the patient that the drops may sting for a few seconds, as if they have been ‘cutting onions’, before the eye becomes numb. The onset of action is around 10 seconds and the duration is around 20-40 minutes. Never give a patient anaesthetic drops to take home as it delays the corneal healing process so should not be used long term.
This is an orange dye that glows green under cobalt blue light. It will enter any defects in the transparent cornea and light them up. This is good for seeing ulcers, dry patches, foreign bodies and any corneal leaks (see Seidels test Figure 7). It does not sting on instillation. It is worth reminding the patient that the tear ducts in their eyes connect to their nose and throat so they may see bright yellow/orange secretions if they blow their nose or spit after having the flurosceine instilled into their eyes.
Dilating eye drops
Phenylephrine 2.5%, Tropicamide 1%,. These are used to dilate the pupil so a thorough fundal examination may be performed. The onset of action is between 20-40 minutes. It tends to be quicker in blue irises. The drops may sting very mildly for a few seconds after instillation. It is important to warn patients that the drops will cause their vision to become blurry and that they should not drive until the effects have worn off. This usually occurs between 1 hour to 6 hours after instillation so safest to warn them not to drive until the following day. A patient with closed angle glaucoma should not be dilated.
Chloramphenicol 0.5% drops or 1% ointment is used to treat bacterial infections e.g. acute bacterial conjunctivitis or for use as a prophylactic following ocular trauma or surgery. The ointment formation is also very lubricating and can help form a protective barrier over a corneal abrasion which also aids comfort. The dose is four times a day for a week. Contact lens wearers are more prone to more aggressive infections such as pseudomonas or acanthoemeba. It is advisable to use a quinolone drop e.g moxifloxacin or levofloxacin eye drops in a contact lens wearer (hourly for 48 hours day and night and then 6 times a day if it is resolving) who has presented with a corneal abrasion or contact lens related ulcer. Such a patient should be referred to an ophthalmologist for further review especially if the lesion is over 1 mm in size.
These are used for the treatment of dry eye which is very common and can cause significant pain. Drops (Hypromellose), gels (Carbomer) and ointments (soft paraffin e.g Lacrilube/ VitaPOS) are available over the counter and can be used as often as needed. The ointments are viscous and may blur vision temporarily but last longer. They are useful if a patient has lagophthalmous (their eyes do not fully close) following a facial nerve palsy to prevent exposure keratopathy.
Steroid eye drops
Should only be prescribed by an ophthalmologist.‘Seidel Positive’.5 See Figure 6 Seidel test.
Figure 6: Seidel Test
5. Eye shield application
If a globe rupture is suspected place a Cartella shield over the injured eye. This will protect the eye from being touched or rubbed inadvertently by the patient but will not place any pressure over the injured eye or be in contact with the eye which may cause a corneal abrasion. If a Cartella shield is not available a shield may be made by cutting the last inch from the base of a polystyrene cup and taping it over the affected eye. See Figure 7 Cartella shield.
Figure 7: Cartella shield.1, 3