Patent Application
20080114387
1. Field of the Invention
The present invention is related to ophthalmic surgical control systems having foot controllers and, more particularly, to foot controllers having foot pedals with movement in both pitch and yaw.
2. Description of Related Art
The use of foot controllers in ophthalmic surgical systems is well known. The foot controllers typically have a foot pedal that pivots about an axis. As the pedal is depressed the foot controller causes a change in some operating function such as ultrasound, irrigation and aspiration, vitrectomy cutter, coagulation, or some other function. The movement or travel in pitch, i.e. up and down, of the pedal is typically divided into one or more regions. For example a total pitch movement of the pedal may be 15° with three regions contained within the 15° of movement. Continuing with the three region example, each region then forms some portion of the total 15° of movement. For example region 1 may be 5% of the pitch movement, region 2 may be 30%, and region 3 50% or more. There is typically some detent that provides tactile feedback to a user as the pedal moves from one region to the next.
In addition to pitch movement, some foot controllers provide movement in yas, i.e. side-to-side movement. These foot controllers are referred to as dual linear foot controllers. One such dual linear foot controller is described in U.S. Pat. No. 6,179,829 and assigned to the same assignee as the present invention and is hereby incorporated in its entirety by reference. The movement in yaw provides another direction of travel for a surgeon to controller further functions of surgery. The yaw movement is typically divided between left and right movements.
Such movement in pitch and yaw provides for effective control of surgical functions but some functions have multiple parameters that need to be adjusted during surgery. For example in controlling ultrasound during phacoemulsification in cataract surgery the function of ultrasound control includes such parameters as power, pulse rate, duty cycle, pulse duration, pulse interval, and minimum/maximum duty cycle switching. Prior art systems did not allow the foot controller to independently control more that one of these parameters at a time. Typically when the foot controller traveled from one region to the next the surgical system would force a parameter to a set value or a set change in value as the parameter of the current region was controlled. This was also true of dual linear foot controllers. If a surgeon wanted to change a parameter other than the one currently programmed to the foot controller, the parameter would have to be changed at the surgical console. This could lead to unwanted delay in the surgery.
Therefore, a need exists to allow independent control of two parameters of the same function to provide for more surgeon control and improve efficiency.
The foot controller 18, best seen in
The pedal 24, located in the center of the foot control, provides two axes of movement and thus allows simultaneous independent control of two system parameters. Both pedal movements are programmable with respect to function and control parameters. In the pitch direction, pedal 24 provides approximately 15° of up/down movement. In the yaw direction, pedal provides approximately 10° of travel from center in both the left and right directions, however, the center (home) position may be offset approximately 5° in either direction. When released, pedal 24 returns to the home (up or center) position. The foot controller 18 includes programmable detents (not shown) that provide tactile feedback to the pitch movement when it moves between different regions.
The following are examples of foot controller 18 configurations>Single Region Pitch Control (one detent position)
The pitch movement is programmed to provide linear control as a function of relative pedal 24 displacement (e.g. 0° to 15° down corresponds to 0% to 100% output). An example of single region pitch control is the linear coagulation function.
There are two programmable regions (two detent positions). When programmed for linear control, the pitch movement is a function of relative pedal 2 displacement in region 2 (e.g., 5° to 15° down corresponds to 0% to 100% output). An example is irrigation/aspiration (I/A) control, where region 1 is for irrigation and region 2 is for linear vacuum or flow.
There are three programmable regions (three detent positions). When programmed for linear control, pitch movement is a function of relative pedal 24 displacement as shown below. An example is single linear ultrasound phases, where region 1 is irrigation, region 2 is linear aspiration, and region 3 is linear power.
The foot controller 18 may be set and programmed to give greater linear yaw movement for either right or left foot operation.
In vitrectomy mode, the outward yaw movement provides ON/OFF cutting control. Each successive outward movement toggles the programmed tool ON or OFF. In ultrasound mode, outward yaw control could be programmed to toggle between different ultrasound submodes. When pedal 24 is released, it returns to the center position. Inward yaw movement controls reflux.
The outward yaw movement provides linear control of the programmed function, relative to pedal 24 displacement (e.g., 0° to 15° displacement corresponds to 0% to 100% output). When pedal 24 is released, it returns to the center position. Inward yaw movements controls reflux.
The pedal 24 may be programmed for use with either the right or left foot. Reflux (if selected) is always activated by inward yaw displacement. For a right foot configuration, reflux is the left (inward). For a left foot configuration, reflux would be to the right. Reflux may only be activated when aspiration is not activated.
For single linear setup, the ultrasound submode sequence (if programmed) is activated by inward or outward yaw when the pedal 24 is in region 2 or region 3. In a Dual Linear setup, the yaw control of the ultrasound submode can only be activated (if programmed) by inward yaw when pedal 24 is in region 2 or region 3.
The present invention allows for the use the two axis of dual linear foot controller 18 to vary two parameters associated with, for example, the ultrasound function for cataract removal. Ultrasound modulations can be described by various parameters such as power, pulse rate, duty cycle, pulse duration, and pulse interval. Typical examples are:
The present invention allows two of the three parameters in the above exemplary modes to be controlled with the pitch and yaw axis of pedal 24. The modes provided are:
In each of the following examples as in the above example the first parameter to be varied may be set for either pitch or yaw and the second parameter is then set to be varied in the direction other than that chosen for the first parameter.
The mapping from the foot controller 18 position to the parameter set point may be linear or non-linear and also may be reversed, such that the minimum foot pedal travel produces the maximum parameter value.
Thus, there has been shown a control system that allows independent control of two parameters of a single function with the pedal of a foot controller. Prior art system only allowed a single parameter of a function to be controlled with the pedal. All parameters but one were fixed console settings in prior art systems. By allowing two parameters to be independently controlled by the foot controller the surgeon has greater flexibility and control, which should result in more efficient surgery.
In addition to the above example of control of the function of ultrasound it is possible to independently control two parameters of other function such as vitrectomy cutters. Control of vitrectomy cutter parameters includes cut rate, duty cycle, min/max cut rate, and burst duration and rate. Another function that may be controlled is fluid flow, where the parameters include at least irrigation and aspiration. Other functions and their associated parameters may be apparent to those skilled in the art and are intended to be within the scope of the present invention.
Additional control modes are possible including modes where multiple parameters may be controlled on the same axis of motion, each with their own mapping from foot control position to parameter value. In addition, it is also possible to have modes where any of the parameters may be set to vary between a minimum and a maximum value automatically over time.
