NBEO Ocular Motility Practice Test

Suppression testing aims to determine whether one eye’s input is being inhibited by the brain to avoid diplopia, and this is best revealed when the two eyes are presented with distinct, separate images that don’t constantly force fusion. Bagolini lenses provide a very gentle, binocular dissociation. When a patient looks at a fixed target through paired, fine-line lenses, each eye sees a faint line that, if fusion is intact, the brain combines into one percept. If one eye is suppressed, the lines may appear incomplete or the patient may report seeing lines from only one eye or in disrupted locations. The patterns map where suppression occurs and how extensive it is, without creating a strong diplopic situation. Red-green filters (or Bangerter filter tests) place translucent color filters in front of each eye and present red and green targets. The patient reports which color image they see and where. If suppression is present, the image from the suppressed eye won’t be seen, or the colors won’t fuse, revealing the eye’s suppression and often its extent. This method directly probes the interocular image competition and is a practical alternative to Worth 4-dot for identifying suppression. Other common tests have different purposes. The Maddox rod test mainly breaks fusion to measure ocular misalignment (phorias) under dissociation, so it’s more about quantifying deviation than mapping suppression patterns. The cover test assesses alignment by alternating occlusion but doesn’t describe which eye is suppressed or how suppression varies across the visual field. Stereoacuity testing evaluates depth perception and the functional outcome of binocular fusion, but it doesn’t systematically map which eye is suppressed or how suppression is distributed. So, Bagolini lenses and red-green filter approaches directly illuminate suppression patterns and are therefore the primary alternatives to Worth 4-dot for this purpose.