Ординатура / Офтальмология / Английские материалы / Eye Emergencies The practitioner’s guide_Field, Tillotson_2008

Eye Emergencies: The practitioner’s guide

extremely dilated pupils. Narcotics such as heroin, codeine, morphine, or pethidine cause miosis. Responses to therapeutic drugs need to be borne in mind with reference to precipitating acute glaucoma. Some travel sickness prevention medications contain hyoscine, which causes some pupil dilation. Similarly, atropine used peri-operatively will also cause pupil dilation.

Examining pupil reflexes

Are the pupils equal and reacting normally? Anisocoria is the technical term to refer to a difference in pupil sizes which may be traumatic, due to a medical disorder, drug induced or peculiar to the individual (idiopathic).

● A small pupil – the pupil of an eye with uveitis is usually smaller due to reflex spasm of the iris spincter muscle. If accompanied by photophobia, this is an indicator for iritis.

● A mid-dilated, oval pupil not reacting to light is characteristic of acute glaucoma.

● An oddly-shaped pupil – evaluate this in conjunction with any past ophthalmic history, particularly injury.

Relative afferent pupillary defect (RAPD)

Always check for this for before dilating for further examination. (See Chapter 9.)

Check the anterior chamber for:

● flat anterior chamber (indicates penetration or post-surgical leak)

● obvious intra-ocular foreign bodies, hypopyon (pus in the anterior chamber) or hyphaema (blood in the anterior chamber).

Based on the history, visual acuity and pen torch examination above, you should now be formulating an initial diagnosis, and deciding whether you will treat or refer this patient.

Slit lamp examination

If you are able to carry out a slit lamp examination, working on the pro forma above, it will provide more detailed information. Small lesions on the eyelids can be evaluated, meibomianitis detected, the depth of corneal abrasions estimated and the anterior chamber thoroughly examined.

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Initial assessment

Check for inflammatory cells in the aqueous by looking in the oblique slit lamp beam under maximum intensity and magnification. The beam should be 1 mm wide and the cells are seen as tiny particles moving slowly through the tiny beam of light. Kanski (2007) suggests that cells should be measured as follows.

The examiner counts the number of cells they can see in the slit lamp beam.

Aqueous flare is an inflammatory haze in the aqueous. Kanski (2007) similarly advises grading of aqueous flare as follows.

Record and evaluate all deviations.

As you begin to make a provisional diagnosis, refer to other sections of this book for further diagnostic and treatment advice.

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Eye Emergencies: The practitioner’s guide

Differential diagnostic guide: acute red eyes

*detectable on slit lamp examination

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Initial assessment

References

Coleman, A. (1997). Where do I stand? Legal implications of telephone triage.

Journal of Clinical Nursing, 6(3): 227–231.

Crouch, R. and Dale, J. (1998) Telephone triage: Identifying the demand, 1.

Nursing Standard, 12(34): 33–38.

DVLA (2006). Visual disorders. Medical Rules. London: DVLA.

Edmonds, E. (1997). Telephone triage: 5 years’ experience. Accident & Emergency Nursing, 5(1): 8–13.

Kanski, J. (2007). Clinical Ophthalmology. Oxford: Butterworth Heinemann.

Marsden, J. (2000). Telephone Triage in an Ophthalmic A & E Department.

London: Whurr.

Nauright, L., Moneyham, L. and Williamson, J. (1999). Telephone triage and consultation: An emerging role for nurses. Nursing Outlook, 47: 219–226.

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Chapter 3

Differential diagnosis of emergency eye conditions

The practitioner needs to bear in mind that there are six principal ophthalmic emergencies that should be diagnosed and given any preliminary treatment necessary prior to immediate referral to the ophthalmologist, day or night. These are: chemical injury, penetrating injury, acute glaucoma, sudden loss of vision, ophthalmia neonatorum (occasionally), and orbital cellulitis. The following text describes these in some detail and includes a number of less serious presentations that the practitioner needs to know about in order to reach a differential diagnosis and evaluate the urgency of the condition.

Advice is given regarding the speed with which the patient may need to be referred to hospital and some details as to how the patient may be treated are given to facilitate practitioners working in minor injuries units and ophthalmic units. For practitioners working in remote, possibly offshore, settings, this information may prove invaluable as medical evacuation may be delayed. Ophthalmic advice can generally be sought via telephone or radio and it would be prudent to assess the patient thoroughly, carry out any relevant initial treatment and check drug stocks prior to calling.

Always document everything thoroughly to ensure a good referral and avoid unnecessary replication and efforts. Remember that your notes may be required by the police in the event of an injury and may even be required for litigation. Finally, if there is a patient complaint against you, excellent treatment supported by good, legible, unambiguous notes will assist your memory concerning what happened and make a major contribution to your defence.

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Eye Emergencies: The practitioner’s guide

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Differential diagnosis of emergency eye conditions

the patient’s eye(s) thoroughly. If the patient has a severe chemical injury, perhaps even involving both eyes, a litre bag of normal saline and an IV-giving set may be prepared for initial irrigation.

Figure 3.1

Severe chemical injury

Immediate action

On arrival in the department or surgery, if you have the test paper required, the pH of both the patient’s eyes should be tested (see ‘Checking the pH’ in Chapter 9). A pH of 7 to 7.5 is considered normal. Above this level, the patient has been in contact with an alkali; below this level, the patient has an acid injury.

Always test the pH of both eyes. Sometimes both are affected, even when the patient thinks that the chemical only went into one eye. It is also useful as a comparison if only one eye is affected, as the pH may vary slightly from person to person.

The patient’s eye(s) should be irrigated until the pH returns to normal (see ‘Irrigating an eye’ in Chapter 9) or until the ophthalmologist gives permission to stop. Instil a local anaesthetic such as oxybuprocaine hydrochloride (Benoxinate) prior to washing and at intervals during the procedure as the irrigating fluid will also rapidly leech out the anaesthetic drops.

Always check for lumps of cement or artex in the corners of the eyes and under the eyelids. Remove any debris promptly with cotton wool buds (this is referred to as fornix sweeping). If the debris is difficult to remove, try an ‘arrow head’ swab or a fine pair of forceps such as Mathalone forceps.

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Eye Emergencies: The practitioner’s guide

When the eye(s) have been washed for a sufficient length of time, perhaps for about ten minutes for a minor injury but at least 30 minutes for a major injury, check the pH again. About ten minutes should be allowed to elapse before doing so, in order that it is not just the irrigation fluid that has just been poured around the eye that is being tested.

With an alkali injury, it is not so much the quantity of fluid that is being used, as the time which is taken bathing the eye with a slow stream of neutral fluid to leech out the alkali, which is important.

Between irrigation sessions, check the visual acuity. The history, which should have been gathered during the irrigation procedure, can be written up.

Morgan lens

A Morgan lens can be used to irrigate the eye(s) whilst staff attend to the patient’s other injuries. They are reasonably expensive, however the device can save practitioner time in a busy A & E department, but should only be used after documented lid eversion and fornix sweeping (Chan et al. 2005). The manufacturers of the Morgan lens recommend use of Ringer’s Lactate solution for irrigation, stating that it is closer to the pH of human tears. They refer to unpublished and unreferenced research performed for them to indicate that irrigation of the eyes with Ringer’s Lactate solution and the Morgan lens is ‘more comfortable to patients’ (www.morganlens.com/faq.html).

Documentation

Documentation must include:

●time of injury

●substance to which the patient has been exposed

●duration of the exposure until the irrigation was started

●pH on arrival (and time of testing)

●duration of the irrigation – how much fluid used

●eyelid eversion

●fornix sweeping

●pH following irrigation (and time of testing).

If the pH has not returned to normal, reassure the patient and commence washing again, for at least 20 minutes, document and reassess.

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Differential diagnosis of emergency eye conditions

Major chemical injuries

Symptoms of major chemical injuries:

●visual acuity may be affected

●difficulty in getting the pH of the eye back to normal

●limbal ischaemia (seen as white, avascular areas at the corneal margins on an eye which is otherwise red)

●avascular areas on eyelid eversion

●severe corneal staining

●hazy cornea.

Management

Patients with major injuries should be referred to the ophthalmologist immediately following initial irrigation. You will need to relay the specific information you have recorded and the results of your eye examination. Arrange for continuing cycles of irrigation whilst the patient waits. He or she may require hospital admission for specialised treatment. This is likely to include vitamin C eye drops (Brodovsky et al. 2000), intensive steroid eye drops and topical antibiotics. Oral prescriptions may include vitamin C tablets. Ensure that the patient is also prescribed oral analgesia.

Minor chemical injuries

Minor injuries, for example perfume and dilute shampoo in the eye, may be treated by an experienced practitioner, provided that:

●the pH of the eye is normal

●the vision in the affected eye is satisfactory

●any corneal staining is minimal

●a check has been made under the eyelids for avascular areas

●there is no limbal ischaemia.

Management

If you have not referred the patient to the ophthalmologist as an emergency, remember that all patients with chemical injuries will require chloramphenicol ointment or fusidic acid 1% (Fucithalmic) after treatment for three to five days after trauma (Fraser et al. 2001). This is because irrigation and handling of the eyelashes and lids may cause infection to be introduced, particularly as the normal, protective tear film is washed away. Additionally, the patient may develop a sore, red eye following the exposure to the chemical. The eye will be dry, having had the

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