The causes of red eye range from trivial to life-threatening, and many general practitioners are uncertain of their ability to diagnose them with the aid of an ophthalmoscope. We tested the hypothesis that, in the assessment of a patient with red eye, a doctor using a slit lamp biomicroscope would not differ in diagnostic accuracy from a doctor using a direct ophthalmoscope. A cross-over study was conducted in 98 patients newly attending an eye casualty department.
71% of diagnoses agreed exactly, and all potentially sight-threatening lesions were either diagnosed correctly or managed appropriately by doctors using an ophthalmoscope. We conclude that the initial diagnosis and management of patients with an acute red eye is not prejudiced by the lack of a slit lamp biomicroscope.