BLOG: Tips to treat DME with MicroPulse laser
In 2020, I wrote a blog titled “Maximizing the benefits of technology by improving the user.” I continue to think that if you aren’t getting the results you want with MicroPulse laser to treat retinal diseases, it may be due to user error.
Here, I want to reiterate a few points because every time I see positive patient results, I am fascinated with how well MicroPulse (Iridex) can work for the right patient with diabetic macular edema.
First, treat early in the disease course. Patients who respond well to MicroPulse are the same patients who respond well to pharmacotherapy. Don’t save MicroPulse only for patients who are not responding to injections. Instead, treat early and then continue with injections until the effects of MicroPulse start to be clear, which is usually 3 to 4 months after treatment. You must have the patience to wait for a slow and steady response, but you will notice that you can extend the time between injections.
Second, in my experience, MicroPulse works best when the central foveal thickness is less than 400 µm. This is another reason to use MicroPulse concurrently with anti-VEGF injections.
Third, make sure you are using high enough power. Because there is no visible endpoint with MicroPulse laser therapy, I start in the continuous-wave mode at 80 mW and titrate the power until I see a gray burn outside the arcades. I then multiply that power by three (up to a maximum of 400 mW) and switch to MicroPulse mode with a 5% duty cycle using the IQ 532 laser (Iridex). I have found that with 532 nm wavelength, the correct power varies between patients, so it is valuable to always perform a test burn.
Fourth, this is a high-density, confluent treatment. I use the TxCell pattern scanning laser delivery system (Iridex) and set a 7 × 7 zero-space grid, 200-µm spot size and 200 millisecond duration. If you are not using TxCell, your spots should overlap. If you are finishing with 200 to 300 spots, that probably is not enough.
Fifth, in my experience, it has been safe to treat over the fovea. I know this makes some surgeons nervous, but I have not had a single patient develop a scotoma because of treating over the fovea. Rather than damaging tissue, MicroPulse stimulates a response from the tissue that produces antiangiogenic inhibitors. Ancillary testing such as OCT, fluorescein angiography and fundus autofluorescence all show a lack of a visible endpoint. Thus far in my treated patients, there has been no loss of vision from treating over the fovea with MicroPulse.
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