The acuity is recorded as a fraction with the numerator as the distance from the patient to the chart over the denominator as the lowest line that more than half the letters can be seen. the largest letter, size 60, can be seen at 60 metres by a person with normal vision. The letters are sized according to distance i.e. The chart is placed at a set distance (usually 6 metres) and each eye is tested individually by covering the other eye.
Traditionally, it has been tested by asking the patient to read letters (known as optotypes) from a chart commonly the Snellen chart. It is an essential component of the assessment of all patients with an eye problem presenting to the ED. Visual acuity is a simple and useful measure of the ability of the eye to resolve fine detail. Activities associated with high velocity fragments hitting the eye include angle grinding and use of a metal chisel with a hammer. Significant blunt injury to the eye often occurs in association with assaults and in sporting situations from direct impact by a ball. It is important to attempt to differentiate blunt from high velocity or potentially penetrating trauma. joint pains suggests generalised inflammatory disorderĪlthough it is tempting to try and differentiate between viral and bacterial conjunctivitis based on the history alone, no reliably accurate method exists.
Is the disturbance partial or a complete loss of vision?Ĭomplete loss of vision in one eye localises pathology to that eye or optic nerve (e.g.A slower onset suggests a more chronic process such as a space occupying lesion. How quickly did the disturbance appear?Ī rapid onset suggests a vascular problem or retinal detachment.Does the disturbance affect one or both eyes?Īcute bilateral eye pathology is rare and often a hemianopic patient will complain of visual loss in one eye rather than both.HistoryĪn ophthalmological history covers not only presenting symptoms and previous eye problems, but must also consider whether an underlying systemic disorder is present.Ĭonsidering three common ED presentations: Visual Lossįeatures of the history may be very useful in discriminating between different causes of visual loss Between 40 and 60% of all eye problems are trauma related and therefore consideration must be given to the rest of the face and head, airway, cervical spine and any other related injuries. Īlthough two thirds of all eye problems can be managed solely by the Emergency Physician, equipment and training are deficient and clinical assessment by junior doctors is poor.Īny patient assessment in the ED must begin with an ABC assessment. įinally, another study demonstrated that emergency nurse practitioners out-performed junior doctors in all aspects of eye assessment and diagnosis. In one, a third of patients did not have their visual acuity tested and in another, a fifth of histories and 59% of examinations were judged to be inadequate. This lack of knowledge is reflected by studies highlighting poor assessment and examination of patients with eye problems presenting to the ED. Although around two thirds of all eye problems are managed solely by the ED many trainee’s receive little or no training in ophthalmic emergencies in their post. Injuries account for the nearly half of the total. Eye problems account for approximately 6% of all attendances to an Emergency Department (ED) in the UK with an incidence of 17.2 ophthalmological emergencies per 1000 population per year.
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