Esterman visual field testing for driving assessment

The binocular Esterman test samples a broad functional field while both eyes are open. In driving assessment, the question is not how much sensitivity is lost at each glaucoma-monitoring location. The question is whether the functional binocular field is wide and clean enough, reliable enough, and free of significant central defects for the relevant licence class.

That makes the Esterman a practical test rather than a perfect driving simulation. Austroads itself notes that visual-field tests do not reproduce the real driving environment, where drivers can move their eyes and head and must respond under variable lighting, motion, and cognitive load.

A good clinician therefore avoids over-interpreting a single printout. The printout is evidence. It must be combined with the patient context, disease prognosis, licence class, and the authority requirements.

Driving is a binocular task for most drivers. The two eyes create a wider field than either eye alone, and defects from one eye can be compensated by the other depending on the location and pattern.

A monocular 24-2 or 30-2 can miss the practical binocular question. It may show disease severity and risk, but it does not directly show the combined field that a driver uses on the road. This is why a significant defect or progressive condition usually pushes the assessment toward binocular Esterman or equivalent testing.

The reverse is also true. A binocular Esterman can look acceptable while one eye has clinically important disease. Do not use it to replace disease monitoring.

Before using DRIVE Fields, read the printout header. Confirm whether the test was binocular, what device produced it, whether fixation monitoring was recorded, whether a false-positive score is printed, and whether the printout layout matches the grid selected in the app.

A surprisingly common error is marking points against the wrong lattice. A Humphrey-style Esterman, a Medmont driving field, a Melbourne Rapid Fields layout, and a Henson driver-test output are not automatically interchangeable. The exact tested locations affect clusters, extent, and the meaning of a missed point.

If the printout is a shaded graphic without clear point-by-point locations, or if the reliability metadata are missing, the safer interpretation is manual review rather than a clean calculated result.

The Esterman score can be useful, but it is not the Austroads rule. Two fields can have the same number of missed points and very different driving implications. A few scattered peripheral misses may be less important than a connected central cluster or a neurological pattern approaching fixation.

When teaching juniors, it helps to read the field in layers. First reliability. Then horizontal extent. Then central 20 degrees. Then pattern recognition: hemianopic, quadrantanopic, bitemporal, vertical edge, lens-frame artefact, or scattered misses. Then licence class.

DRIVE Fields follows a similar logic. It is not trying to produce a magic total score. It is trying to preserve the clinically relevant distinctions that can disappear when a printout is reduced to a single number.

Driving relies heavily on detecting hazards, lane position, road markings, pedestrians, and vehicles. Central and paracentral field loss can matter because it affects detection and recognition near fixation. Inferior field can matter for road surface, lane markings, and near obstacles.

The Esterman pattern samples these regions in a practical way, but it should not be over-sold. It does not test glare, contrast sensitivity, divided attention, neck rotation, scanning behaviour, or real traffic response.

Those limitations are exactly why Austroads includes additional clinical factors such as duration, adaptation, driving record, driving task, and cognitive or physical comorbidity.

A useful report should not simply say pass or fail. It should record the test type, device or printout source, reliability, horizontal extent, central defect pattern, licence class, and whether any manual-review caveats apply.

If the field is borderline, note the context: longstanding versus new defect, progressive versus stable condition, private versus commercial driving, and whether the patient needs conditional consideration rather than unconditional approval.

If a licensing form is being completed, keep the original visual-field printout. DRIVE Fields output can help structure the clinical explanation, but the printout remains the source evidence.