Common Ophthalmic Emergencies

G. D. Khare; R. C. Andrew Symons; D. V. Do

Disclosures

Int J Clin Pract. 2008;62(11):1776-1784. 

In This Article

Physical Examination

One of the keys for the non-ophthalmologist to perform a thorough eye examination is to look for asymmetry between the two eyes. Ophthalmic examination is a very specialised area, and referral to an ophthalmologist is often required because of difficulty in interpretation of findings.

Visual Acuity

Visual acuity is the most easily measured element of visual function and should always be assessed before administration of any diagnostic test or treatment. Visual acuity is most commonly graded using a Snellen chart. In ophthalmic clinics the Early Treatment Diabetic Retinopathy Study chart is also often used. In the emergency room an estimate of Snellen visual acuity can be made with a hand-held card. A diagnosis must be made to explain any substantial decline in visual acuity or the patient must be referred to an ophthalmologist.

Visual Field

In an emergency room, visual fields should be evaluated by confrontation testing with the examiner's fingers or hands. Acutely diminished visual fields are most frequently because of retinal (e.g. retinal detachment) and neurological diseases (e.g. stroke).

Colour Vision

Defects in the red-green axis of colour vision are most easily tested using Ishihara plates. Unilateral red desaturation can be tested by asking the patient to compare the colour intensity of a red target, such as the top of a bottle of mydriatic eye drops. Asymmetry of colour perception is usually a sign of optic nerve pathology.

Eye Movements

In the emergency department, eye movements including adduction, abduction, and up- and down-gaze should be checked, as well as combinations of these. In cases of diplopia where an ocular motility problem cannot be determined by these manoeuvres alone, cover and alternate-cover tests at near and distance should be performed. It is sometimes worth checking whether diplopia is present when one eye is covered. Monocular diplopia generally results from abnormalities of the affected eye's optical system.

Pupils

The pupillary light reflex is of great importance in assessing retinal and optic nerve function. Examination of the pupils is also an important part of the evaluation of the oculomotor nerve and of the sympathetic nervous system in Horner's syndrome. Of particular importance is to evaluate for a relative afferent pupillary defect or Marcus-Gunn pupil using the 'swinging light test'. Presence of a relative afferent pupillary defect should lead to ophthalmologic referral.

Intraocular Pressure

Elevated IOP can lead to glaucomatous visual field loss. The rate of field loss depends on the pressure and on the susceptibility of the individual. The most commonly used instruments for accurately measuring pressure are the Tonopen and the Goldmann applanation tonometer. The Tonopen is a small, portable device that is easy to use and is appropriate for use in the ER by a non-ophthalmologist. If no tonopen is available, a crude gauge of IOP can be gained by palpation of the globe through the eyelid.

Anterior Segment

The anterior segment of the eye is best examined using the slit lamp. Biomicroscopic examinations of the lids, conjunctiva, cornea, anterior chamber, iris, lens and anterior vitreous should be performed. Gonioscopy is a highly specialised examination technique used particularly in the assessment of the anterior chamber angle, especially in cases of suspected angle-closure glaucoma. If no slit lamp is available, a hand-held penlight or flashlight can assist in viewing the cornea, iris and pupil.

Posterior Segment

The posterior segment can be examined at the slit lamp using a 90D or similar lens, and by direct and indirect ophthalmoscopy. Most non-specialists are most familiar with direct ophthalmoscopy and this examination should be performed to assess the retina and optic disc head. The retina should be checked, as appropriate, for abnormalities of the vasculature, haemorrhages, oedema, lipid exudates, retinitis, retinal elevation, retinal tears or breaks and retinal detachment. The vitreous should be checked for inflammatory changes, haemorrhage and posterior vitreous detachment. The optic nerve should be evaluated for cupping, atrophy, elevation and swelling, as well as for vascular abnormalities at the nerve.

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