Emergency eye trolley setup

History

Ocular injuries, however trivial, are a frightening experience for the patient, who may have a deep-rooted fear of blindness. The incidence of injuries varies with the environment and protective measures taken. The major injuries result from blunt trauma or penetrating injuries to the globe, with or without the retention of a foreign body. Mechanical interference with eye movement may result from orbital injury, either haematoma or interference with muscle function. Similarly, neurotrauma may disturb the visual pathways or ocular motor nerves.

It is necessary to elicit a history of the patient’s prior visual status, including the wearing of glasses or contact lenses and ocular medication.

Visual acuity

After an eye toilet to remove any debris from the eyelids, vision is tested by a distance Snellen chart, if necessary using a pinhole device as a rough focusing aid. Vision less than 6/60 Snellen may be graded by the patient’s ability to count fingers at a measured distance, discern hand movements or to project the direction of a light from various angles. The eye not being tested must be completely shielded by an opaque occluder.

It is essential to assess early whether the patient has sustained a relatively minor superficial injury or a severe injury which may be either blunt or penetrating. Reassurance and extreme gentleness in examining the eye, using topical anaesthetic, will allow a more definite assessment to be made in the ED. With penetrating trauma, any external pressure on the eye may result in ocular structures being squeezed out of the wound, drastically worsening the prognosis.

To open lids that are adherent due to blood or discharge, gently bathe with sterile saline. Wipe the eyelid skin dry and apply gentle distractive pressure to skin below the brow and below the lower lid, i.e. over bony orbital rim to open the lids. Note that no pressure should be applied to the globe.

Superficial injury

Penetrating injury

A careful history is important in assessing penetrating injury, including prior visual status and the use of contact lenses or spectacles. Occupational trauma may be due to high-speed penetrating metal fragments. Agricultural trauma often involves heavily contaminated implements.

Examination of the eye involves the instillation of sterile topical anaesthetic drops, followed by a gentle eye toilet removing debris, clot and glass from the face and lids. The lids should be opened without pressure (Fig. 16.1.1). The penetration may be evidenced by an obvious laceration or presence of prolapsed tissue with collapse of the globe. Conjunctival oedema (chemosis) and low intraocular pressure (IOP) may indicate an occult perforation or bursting injury.

Fig. 16.1.1 Emergency department diagnosis of penetrating injury. FB, foreign body.

When a penetrating injury is either suspected or established, the patient must be transferred without delay to a centre where appropriate surgical facilities are available. During transport, the eye should be covered with a sterile pad and a plastic cone. Vomiting should be prevented with antiemetics, and the fasted patient given intravenous fluids as necessary.

Penetrating trauma involving the cornea has the best prognosis. Lens involvement requires removal of the traumatized lens and usually a staged implantation of an intraocular lens. Posterior segment trauma involving tears or perforation of the choroid and retina requires staged vitreo–retinal surgery and has a guarded prognosis. Uncommonly, penetrating trauma excites an autoimmune reaction resulting in a destructive inflammation involving the uninjured fellow eye – sympathetic ophthalmitis. Long-term follow-up of all penetrating ocular trauma is mandatory.

Blunt trauma

Concussion of the globe may cause tearing of the iris root, resulting in blood in the anterior chamber. A hyphema greater than one-third of the anterior chamber usually indicates some damage to the drainage angle, and may also be associated with concussive lens damage. Uninterrupted absorption of the hyphema is essential, and is aided by sedation and an admission to hospital. The affected eye is padded and the patient nursed semirecumbent to encourage sedimentation of the blood in the anterior chamber to clear as much of the angle as possible. A hyphema may cause considerable pain due to raised IOP. To lower the pressure, oral or intravenous acetazolamide 500 mg initially is required.

Pain is relieved by paracetamol or narcotics, with antiemetics if necessary. Aspirin in any form should be avoided as it increases the risk of secondary haemorrhage. The patient should remain in bed until the blood has completely cleared from the anterior chamber. Bleeding recurs in up to 10% of patients, usually due to early mobilization in those with extensive iris damage. Total hyphema has a poor prognosis because of secondary glaucoma, field loss and corneal opacification. When angle damage occurs, long-term follow-up after hyphema is required to determine whether the IOP is raised. The fundus requires careful examination after the hyphema has cleared completely, to exclude a traumatic retinal tear, which may be heralded by sudden onset of flashes and floaters.

Chemical burns

Chemical trauma requires priority assessment on arrival at an emergency centre.

Alcohol and solvent burns occur from splashes while painting and cleaning. Although the epithelium is frequently burnt, it regenerates rapidly. The condition is very painful initially, but heals with topical antibiotic and patching for 48 h.

Alkali and acid burns are potentially more serious because of the ability of the burning agent to alter the pH in the anterior chamber of the eye and inflict chemical damage on the iris and lens. Caustic soda, lime and plaster, commonly used in industry, may inflict painful, deep and destructive ocular burns. Splashes of acids, such as sulphuric and hydrochloric, if concentrated, will cause equally destructive injury.

The first principle of management at the injury site is copious irrigation of the eyes for at least 10 min with running water. Assessment of the ocular burn should be done using topical anaesthetic drops and fluorescein staining to determine the area of surface injury. The eyelids should be everted and the fornices carefully examined and swept gently with a cotton bud to ensure there is no particulate caustic agent remaining.

Chemical burns where the epithelium is intact or minimally disturbed can usually wait 24 h before review by an ophthalmologist. Burns involving more than one-third of the epithelium and the corneal edge, with any clouding of the cornea, are potentially more serious as subsequent melting of the cornea by collagenase action may ensue. These burns should all be further irrigated in the ED with a buffered sterile solution such as lactated Ringer’s (Hartmann’s). The irrigation should continue until the tears are neutral to litmus testing.

More serious caustic injuries have shown a significant improvement in outcome with the introduction of 10% citrate and ascorbate drops, commencing 2-hourly for 48 h and reducing over the week, in combination with 1 g oral ascorbic acid daily. This regimen has an inhibitory effect on corneal melting. Topical antibiotic (chloramphenicol) and soluble steroids such as prednisolone phosphate 0.5% decrease inflammation.

Initial treatment of caustic injury:

A minor injury is defined as less than one-third epithelial loss and a clear cornea. A major injury is a large epithelial defect, a conjunctival burn and a hazy media.

For major injury commence ascorbic acid 1 g daily and 10% topical ascorbate hourly.