9 positions of gaze

What it measures

The nine positions of gaze record eye position in the nine diagnostic directions: primary position, and the eight directions that separate the actions of the extraocular muscles. The record is photographic, so what it captures is appearance: the size and direction of any deviation in each position, limitation of movement, lid position, and head posture.

The test produces images rather than a number. Its value comes from consistency: the same framing, lighting and nine directions each time make two sessions comparable side by side, which a written description does not achieve.

How it is administered

The patient sits facing the camera, head square and at lens height. Spectacles are removed if the frame or a reflection hides the eye. The room is evenly lit from the front, with no window behind the patient and no strong light casting a shadow across one side of the face.

The patient follows a fixation target into each of the nine positions and holds while the photograph is taken. The head must stay still. A patient who turns the head instead of moving the eyes hides the limitation the test exists to record.

The clinician sets the camera at eye level, keeps framing constant using the on-screen guide, and checks each photograph before moving to the next position. The corneal light reflex should be visible in every frame. Blinks are re-taken.

Reading the result

VisReed assembles the nine photographs into a fixed layout and exports it as one sheet. It measures nothing from the images.

Compare the two eyes within each frame, then the same frame across sessions. The position of the corneal light reflex gives an estimate of the deviation in that direction of gaze. A limitation shows as an eye that does not reach the excursion of its fellow.

The pattern across the nine frames carries the information. A limitation in one direction points towards a single muscle or nerve. A symmetrical limitation in every direction fits a myopathy or a supranuclear cause. Lid position across the frames can show lid retraction, lid lag, or a change in ptosis with gaze.

The composite is documentation. Numbers come from the cover test with prisms, or from a motility chart such as Hess-Weiss.

When it is used

The set is used to document a new palsy or restriction at presentation, and to follow it. It is used in thyroid eye disease, orbital trauma, and cranial nerve palsy, where change over months is the question.

It is used before and after strabismus surgery, in referral letters and second opinions where an image carries more than a description, and in teaching and case records. It also records a compensatory head posture, which is easily lost from a written note.

Limitations

This is a record, not a measurement. Degrees of limitation cannot be read reliably off a photograph, and grading underaction from images is subjective and varies between observers.

Camera angle, distance and lens change apparent eye position. A frame taken slightly off axis can imitate a deviation, or hide one. Comparability between sessions depends entirely on repeating the setup.

Ambient lighting is not controlled. Shadows and reflections obscure the corneal light reflex. Image quality depends on the device camera.

Head position is not controlled. Any turn or tilt shifts every frame in the set.

The photographs and the sheet stay in the browser on the device used, and nothing is sent anywhere. Download the sheet and file it with the record.

Photographs of patients are identifiable personal data. Keep them only with explicit consent, and only for as long as the clinical record requires.

Validated status means this implementation is considered ready for clinical use on this platform. It does not mean a published study has shown equivalence to another method of documenting motility. The set records the motility examination, it does not replace it.