18
70375-EN Rev B
•
MicroPulse Duty Cycle
Typical MicroPulse treatment settings deliver 500 MicroPulse applications per second. 500 Hz defines a
2-millisecond (ms) period, which is the sum of Laser ON time + Laser OFF time.
MicroPulse duty cycle examples:
5% duty cycle = 0.1 ms ON + 1.9 ms OFF time
10% duty cycle = 0.2 ms ON + 1.8 ms OFF time
15% duty cycle = 0.3 ms ON + 1.7 ms OFF time
In contrast, a Continuous Wave (CW) exposure, which is always ON, can be thought of as having a
duty cycle of 100%.
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Spacing Between Spots and Duty Cycle
MicroPulse applications, especially those produced using lower duty cycles, produce less thermal
diffusion. In order to effect a sufficient volume of target tissue to achieve a desired therapeutic effect,
MicroPulse laser applications must be more closely spaced, or even contiguous (0 spacing).
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Patient Sensitivity to Photocoagulation
Some patients report a more heightened level of sensation or pain during laser photocoagulation.
Patient comfort can often be significantly enhanced by appropriate use of the following treatment
parameters and considerations:
o
Shorter pulses (<50 ms)
o
Smaller spot sizes
o
Lower energy pulses
o
Milder laser lesion endpoints
Also, the peripheral retina is both thinner and more sensitive than the posterior retina. Laser treatment
parameters may need to be readjusted when treating the peripheral retina.
Laser Settings
It is the physician's responsibility to determine the appropriate treatment parameters for each patient being
treated.
The information in the following tables is intended to provide guidance only for treatment settings,
which are not prescriptive for any condition. The operative needs of each patient should be individually
evaluated based on the specific indication, treatment location, and patient-specific characteristics. If
uncertain of expected clinical response, always start with conservative settings and increase laser power
and/or duration settings in small steps. Proper delivery of both CW and MicroPulse laser is verified as
delivered by internal power monitoring controls, within the respective laser console.
532
NM
T
YPICAL
L
ASER
T
REATMENT
P
ARAMETERS FOR
O
CULAR
P
HOTOCOAGULATION
(Please note that multi-spot pattern mode is available with 100 µm and larger spot sizes.)
532 nm Continuous Wave Treatment
Treatment
Spot Size at Target (µm)
Power (mW)
Exposure Duration (ms)
Retinal Photocoagulation
50 - 1000
50 - 2000
10 - 1000
Trabeculoplasty
50 - 200
500 - 2000
100 - 500
Iridotomy
50 - 200
500 - 2000
100 - 300
532 nm MicroPulse Treatment*
Treatment
Spot Size at
Target (µm)
Power
(mW)
Duty Cycle
(500 Hz)
Exposure
Duration (ms)
Retinal Photocoagulation
50 - 1000
100 - 2000
2.5% to 25%
10 - 1000
Trabeculoplasty
100 - 500
500 - 2000
2.5% to 25%
100 - 500
