The measurement of distance visual acuity is the most familiar and most widely used test of visual function. However, this is only one in a battery of tests used in the assessment of patients with visual impairment. A full and comprehensive assessment helps to build a picture of the need and urgency for further treatment, including the provision of rehabilitative interventions and to predict the performance of low-vision devices.

This review outlines some of the principal tests and strategies available for the clinical assessment of visually impaired patients that are readily available to practising optometrists. The generic principles of the key visual functions assessed in the low-vision assessment are outlined, together with a critical review of those instruments still currently used within optometric practice which may not yield the most reliable results.