Synopsis
Measure central visual function reproducibly, recognise the contribution and limits of optical correction, and use abnormal findings to guide investigation and referral.
- Measure each eye independently at the chart's specified distance, using habitual distance correction and documenting exactly what was worn.
- Keep the fellow eye fully covered without pressing on it; binocular testing alone can conceal marked unilateral impairment.
- Record the chart, viewing distance, right and left results, correction and any pinhole response rather than writing simply that vision is normal.
Key red flags
Sudden unexplained reduction in either eye, a new field defect, severe pain or neurological symptoms requires urgent specialist assessment; good vision in the other eye does not reduce the urgency.
Investigation priorities
Establish the presenting central visual function of each eye separately.
Management branches
A patient presents with an eye complaint or needs a baseline visual assessment.
- Identify the patient, explain monocular testing and check which distance correction they normally use, including whether contact lenses should be removed for the clinical problem.
- Position the patient at the chart's marked distance with suitable lighting and test each eye using an occluder that prevents peeking without applying pressure.