Monocular drivers and visual-field assessment in Australia

A patient with one good eye may have excellent central acuity and still face driving-relevant limitations. Monocular vision reduces binocular field, removes stereopsis, and can affect judgement of distance and gaps, especially soon after vision loss.

Austroads notes that the nose obstructs part of the medial visual field in monocular drivers and that other visual function deficits may be present. That is why monocular cases need more than a quick acuity check.

The clinical question is not whether the remaining eye sees well in a narrow sense. It is whether the overall visual function, field extent, adaptation, and driving task support safe driving within the relevant licence pathway.

For private drivers, Austroads allows conditional licence consideration when the horizontal field is 110 degrees and the visual acuity in the better eye is satisfactory. The authority makes the final decision.

This is a conditional pathway, not an unconditional all-clear. The report should usually discuss stability, cause, duration, visual acuity, field extent, and whether the patient has adapted.

In NSW and other practical settings, clinicians may still prefer binocular Esterman or equivalent testing because some authorities need the visual field reported in degrees.

Commercial monocular driving is a more cautious area. Austroads says people with monocular vision are generally not fit to drive a commercial vehicle, but conditional consideration can occur in specific circumstances with 140 degrees horizontal field, satisfactory acuity, no other field loss likely to impede driving, and optometrist or ophthalmologist assessment.

The word generally matters. It prevents overconfidence. A commercial monocular assessment should be careful about vehicle type, driving hours, routes, review interval, other eye disease risk, and whether the patient truly has stable adaptation.

If there is progressive disease in the remaining eye, borderline extent, unreliable testing, or any additional neurological or ocular field loss, the report should be conservative.

Austroads describes a period of adaptation after sudden loss of an eye or most vision in one eye, usually three months, before reassessment. The reason is practical: depth perception, scanning behaviour, and confidence need time to settle.

Patients may feel visually capable before they have adapted safely to complex road environments. A calm explanation can help: the waiting period is not a punishment; it is a safety and adaptation period.

At reassessment, document the cause, duration, stability, acuity, field, symptoms, and any restrictions that might support conditional consideration.

If there are no symptoms, no family history or risk factors, no progressive condition, and monocular automated static perimetry shows no field concern, Austroads allows this information to be sufficient in some contexts.

However, if there is any field defect, progressive disease, symptoms, or authority requirement for degrees, binocular Esterman or a validated equivalent is usually the cleaner pathway.

Do not assume that the remaining eye is risk-free. A monocular patient with glaucoma risk, diabetic retinopathy, retinal disease, neurological symptoms, or unexplained field complaints needs formal assessment beyond a simple screen.

A good monocular report states the cause and timing of monocular status, best-eye acuity, field extent, reliability, evidence of stability or adaptation, and licence class. It should also recommend appropriate review of the better eye.

Avoid saying the patient is "safe because one eye is normal" without discussing field, adaptation, and driving task. Also avoid overstating DRIVE Fields output as a licensing decision.

If the case is borderline, write a structured conditional-support statement rather than trying to stretch the result into an unconditional pass.