Visual fields

Visual acuity is dependent on central vision only. The assessment of visual fields may yield vital information; unfortunately, visual field defects are often missed.

To examine the visual field in the left eye:

• the patient should be seated in front of the examiner, about an arm's length away, with the right eye covered
• the examiner should close his left eye and ask the patient to look at the pupil of his right eye
• the examiner holds up one or two fingers midway between himself and the patient
• the patient is asked to say how many fingers there are
• this is done in the four quadrants of vision i.e. superotemporal, superonasal, inferotemporal and infero- nasal
• the patient's visual field is compared with the examiner's

The method outlined above is suitable for the detection of gross visual field defects. An alternative method involves testing of the field of red colour vision using a red hat pin.

To detect subtle defects, and to monitor the progression of defects, perimetry is performed in a specialist centre.

Click here for video of examination of visual fields