Orthoptic maze

What it measures

The orthoptic maze puts pursuit and fixation under a visuomotor load. The patient follows a path through a maze with the eyes and traces it with a finger or pointer, staying inside the corridor.

Following the line demands smooth pursuit along an irregular trajectory, stable fixation at junctions, and a saccade whenever the path changes direction. The hand movement adds an eye-hand coordination demand that a plain moving target does not have.

It is a functional task. It does not isolate one muscle or one pathway. It shows how the oculomotor system holds up when the eyes are doing something rather than watching something. Patients who track a plain target normally sometimes struggle here, because planning and motor output are added.

How it is administered

The patient sits about 30 to 40 cm from the screen with habitual near correction, both eyes open, head still and able to see the whole maze without turning. The screen sits at eye level in moderate, steady lighting with no reflection.

The task is to trace from the start marker to the end marker without leaving the corridor and without lifting the finger. Pace matters more than speed. A patient who rushes produces errors that say nothing about their oculomotor control.

The clinician chooses a level suited to the patient's age and ability, starting simple, and watches the eyes rather than the screen, noting head movement, loss of place, re-tracing, and use of the finger to keep place.

Reading the result

VisReed records two things: whether the maze was completed, and the time taken in seconds. The path itself is not scored, so nothing measures how far the trace wandered or how often it touched a wall.

Pursuit and fixation stability under load are judged by the clinician, from the trace on the screen, from the time, and from watching the patient.

A path that stays inside the corridor with few corrections indicates that pursuit and fixation held. Wandering, overshoot at turns, and repeated returns to a junction indicate that they did not.

Where the errors sit carries information. Errors concentrated at direction changes point to saccadic and fixation control. Errors spread along straight sections point to pursuit.

Time is context for path quality rather than a score in itself.

Observation during the task carries as much as the trace: turning the head instead of moving the eyes, losing place, needing a finger to hold place, or a report that the page moves.

Compare a patient with their own earlier attempt at the same level. Different mazes are not equivalent.

When it is used

The maze screens children with reading difficulty or a suspected oculomotor problem, because the task resembles what reading demands of the eyes.

It is also used as a training exercise, repeated over a course of orthoptic therapy, and after head injury as part of a wider look at visual processing. A poor performance is a reason to look further, not a diagnosis.

Limitations

This test is in beta. Treat the output as indicative and not as a settled clinical measure.

It isolates nothing. Failure can come from oculomotor control, attention, motor coordination, visual processing, or misunderstanding the task, and the maze cannot separate them.

There is no eye movement recording, and the trace is not analysed. Eye position and path quality are both inferred from what the clinician sees, so any judgement of either has to be written into the notes during the attempt.

No published norms exist for the task in this form, so compare within a patient across sessions. The practice effect is strong, and a repeated maze becomes a memory task.

Viewing distance is not fixed and screen size is not controlled, so the angular size of the path varies. On a small screen the whole maze subtends a small angle and demands much less eye movement.

The input device changes the task. A finger on a touchscreen, a stylus and a mouse are three different motor tasks, and results from them are not comparable.