Lightbar “length” refers to the total distance travelled by the illuminated dot from side to side. It does not describe the physical length of the lightbar, the duration of a set or the speed of movement.
That distinction is useful because travel length changes the visual path the client follows. It is an equipment adjustment—not a clinical dose—and there is no single travel length that is automatically right for every person, room or stage of treatment.
What the length control changes
On the Mangrove Simple EMDR controller, the length knob changes the dot’s total horizontal travel and keeps that travel centred on the lightbar. At its maximum setting, the path extends to 66 centimetres.
A shorter setting creates a narrower left-to-right path around the centre of the bar. A longer setting uses more of the available visual width. The physical lightbar stays in the same position; only the distance travelled by the light changes.
Length and speed are different—but they interact
Speed describes how quickly the moving dot travels. Length describes how far it travels. Although these controls perform different functions, they interact on the Mangrove system: shortening the travel path can increase the apparent movement rate if the speed control is left unchanged.
For that reason, Mangrove’s operating guidance recommends setting amplitude and travel length before making the final speed adjustment. If length is changed later, recheck the resulting pace rather than assuming the previous speed setting still produces the same experience.
Position the lightbar before choosing the path
Travel length is easier to assess after the lightbar has been positioned for the client. A path that seems modest when the bar is further away may feel much wider when it is closer. Chair position, viewing distance, lightbar height and angle all influence how readily the client can follow the dot.
Set up the tripod or mount securely, seat the client in their usual position and check that the centre of the lightbar is easy to view without an awkward head or neck position. The client should not need to turn their whole head simply because the selected path exceeds what is comfortable for them to track.
Use a neutral demonstration
Before relying on a visual setting during clinical work, demonstrate it without suggesting what the client should experience. Begin with a clearly visible, moderate path and pace, then invite specific feedback:
- Can the dot be followed without straining?
- Does the path feel too wide or too narrow?
- Is the pace easy to perceive?
- Is the lightbar positioned at a comfortable height and distance?
- Would another modality be more suitable if visual tracking is uncomfortable or impractical?
The purpose of this check is equipment familiarisation and comfort. It is not a substitute for EMDR preparation, case conceptualisation or trained clinical assessment.
Adjust one variable at a time
If the visual experience needs refining, changing one control at a time makes the result easier to interpret. For example, adjust travel length while leaving colour and brightness-related settings unchanged, then recheck speed because the movement rate may have shifted.
Making several changes together can make it unclear whether the client is responding to path width, pace, colour, room lighting or the lightbar’s position. Small, deliberate adjustments help keep the conversation precise and the technology in the background.
Do not confuse a wider path with “more” EMDR
A longer visual path is not automatically more therapeutic, and a shorter path is not automatically gentler or less effective. EMDR is a structured psychotherapy, not an equipment setting. The type and length of bilateral stimulation sets vary between clients, and the clinician chooses how to proceed based on training, observation and the client’s report.
The lightbar’s length control exists to make the visual path adjustable. It should not be used to imply a guaranteed clinical effect or a universal formula.
Recheck when the room changes
If the lightbar, tripod or chairs have been moved, do not assume the previous setting will look the same. Recheck viewing distance, centring and travel length from the client’s position. The same applies when equipment is transported between consulting rooms.
A brief visual check before the session can confirm that the dot remains centred, travels smoothly and stops when expected. If the client reports visual discomfort or cannot follow the path comfortably, pause and reassess rather than asking them to persist.
A flexible path, guided by the practitioner
An adjustable lightbar allows the visual path to suit different room layouts and client presentations. Its value lies in practical flexibility: the clinician can select a clear, observable path and refine it without moving the entire device.
As with every equipment control, travel length supports delivery. Accredited training, client feedback and professional judgement determine whether and how visual bilateral stimulation is used.
Explore the Mangrove Simple EMDR Set, including its adjustable RGB lightbar, tactile tappers and optional stereo audio.