Ophthalmic emergencies

Published on 14/03/2015 by admin

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Chapter 36 Ophthalmic emergencies

Michael R. Delaney, Iromi Samarasinghe

PRINCIPLES OF EXAMINATION

1. All cases of suspected eye injuries need a good history and examination of:

• visual acuity—visual loss sudden/gradual; central/peripheral; monocular/binocular
• pupillary reactions
• the fundus
• ocular movement
• fields to confrontation
• lids and ocular adnexae.

2. Do not put pressure on the eye to examine it (especially if there is a possible penetrating injury).
3. Do not use atropine drops to dilate the pupil. Use a short-acting mydriatic, e.g. tropicamide 1%, and only if essential.
4. Do not use mydriatics in cases where the ocular state and optic nerve function may need to be monitored.
5. CT scan or X-ray the orbits in all cases of a suspected intraocular foreign body, especially if the patient was using a hammer on metal, e.g. a chisel. Note: Request X-ray with eyes in up and down gazes.

COMMON PITFALLS

• Never use steroid drops in the emergency department in initial treatment. Refer for further assessment.
• Eye swabs need to be plated out directly.
• Avoid contaminated diagnostic medications. Use only sterile drop solutions.
• Always pad an eye after instilling local anaesthetic.
• Never give local anaesthetic drops to the patient to take away and use.
• Only use a short-acting cycloplegic, e.g. cyclopentolate 1% or homatropine 2%, if necessary.
• Do not apply ointment in cases of suspected penetrating injury.
• Do not persist in trying to remove a corneal foreign body if it is not easily removed—refer for ophthalmology review according to your hospital’s practice.
• Always provide adequate systemic analgesia in cases of corneal injury.
• When in doubt seek an ophthalmic consultation.

USE OF THE SLIT LAMP

These remarks apply to the Haag Streit slit lamp, but the principles apply to all slit lamps. The patient and the examining doctor must both be comfortable. In particular, the patient should not be straining to keep the chin on the chin rest, and the patient’s forehead must rest comfortably against the forehead strap. The eye should be at the level of the black mark on the side of the two columns that hold the chin rest and forehead strap; this is achieved by adjusting the height of the chin rest. The slit lamp should then be adjusted so that it is in its mid position, allowing a full range of vertical and horizontal movement. This position is adjusted by rotating the joystick which controls the height of the slit lamp as well as the movement of the slit lamp in all directions, thereby controlling its focus.

After the patient is positioned correctly, the eye can be examined. On the bottom of the rotating light source column of the slit lamp is a knob that controls the width of the slit beam. Further up the column, immediately under the globe housing, is a control to adjust the intensity of the light; this same control also allows the insertion of a cobalt blue filter into the light, producing the characteristic blue light used to detect corneal ulcers with fluorescein dye. Near this control is another control that adjusts the height of the slit beam.

The slit lamp can be used in many ways. The easiest is simply to use it as a high-powered illumination source with magnification using the broad beam; this is particularly useful to detect corneal ulceration after instilling fluorescein dye and using the cobalt blue filter. To detect and assess iritis, a narrow slit beam can be shone through the anterior chamber; this will highlight any flare or cells. A slit beam can be shone directly through the pupil to retro-illuminate the iris using the red reflex; this is also a useful way of assessing the clarity of the media.

Intraocular pressures are measured using the application tonometer, which is either attached to the slit lamp on a swinging arm or is detached from the slit lamp and is placed on the platform immediately in front of the eye pieces.

TRAUMA

Foreign bodies

Conjunctiva

Carefully examine posterior lid surfaces and fornices by everting the upper lid. Remove with moist swabstick or fine forceps.

Cornea

• Remove with a sterile swab stick or sterile 25-gauge needle. Do not attempt to remove rust ring. Apply antibiotic ointment and pad firmly.
• Patients with a residual rust ring and foreign body remnants must be referred.

Intraocular

• Always suspect if there has been an eye injury after using a metal hammer on metal, or where there have been high-velocity particles.
• There are often minimal signs. CT scan or X-ray of the orbit is mandatory.
• Treat as a penetrating injury and organise urgent ophthalmic consultation.

Corneal abrasions

• Examine the eye under cobalt blue light after instilling local anaesthetic drops (amethocaine 0.5%) and fluorescein.
• Check for subtarsal foreign body.
• Treat with chloromphenicol 1% antibiotic ointment and firm pad for 24 hours and provide adequate analgesia.

Lid lacerations

• All lid lacerations must be carefully assessed to exclude penetrating eye injury.
• Lacerations nasal to the punctum on either the upper or lower eyelids should be referred to an ophthalmologist to exclude damage to the nasolacrimal drainage system.
• Inspect punctum and look for lacerations to the canaliculus, which require prompt repair.
• Lacerations through the lid margin need meticulous repair to prevent lid notching. Refer to ophthalmology service according to your hospital’s practice.

Burns

Chemical: acid or alkali

1. Immediate irrigation with copious amounts of water or saline solution for at least 30 minutes until the pH neutralises to 7.5. Use universal indicator paper to check corneal pH after every litre of fluid irrigation.
2. If pain limits eye opening, instil local anaesthetic drops.
3. Alkali burns from lime, mortar and plaster are the most damaging of all chemical injuries. All particles of lime must be removed using a cotton bud or fine forceps. Evert lids to inspect fornices.

Acid burns commonly result from exposure to car battery fluid, toilet cleaners and pool cleaners.

4. All chemical burns should be referred to ophthalmology on the same day. Systemic analgesia is often required.

Thermal burns

Remove any obvious loose foreign bodies after instilling anaesthetic drops. Start antibiotic drops and pad if possible.

Flash burns

Symptoms appear hours after exposure to sunlamps or welding arcs without eye protection. These are intensely painful with blepharospasm, tearing and redness. Pain can start up to 6–12 hours after injury and last for 24 hours.

Examination is only possible after topical anaesthesia. Slit lamp examination with fluorescein will show widespread epithelial defects bilaterally.

Management

1. Apply chloramphenicol 1% ointment and pad. Cycloplegics may be needed to minimise severe eye pain (homatropine 5% BD for 3 days). Systemic analgesia and sedation are usually needed.
2. Review in 24 hours.

Blunt ocular trauma

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