Laser therapy with MicroPulse
However, surgeons have been witnessing a paradigm shift in laser therapy for many ocular diseases. Work done surrounding retinal photocoagulation has demonstrated that rather than decreasing the production of angiogenic factors due to destruction of retinal cells, selective destruction of photoreceptors with laser while sparing the inner retina begins a healing cascade that increases the availability of oxygen while reducing the angiogenic and permeability factors.4
A very directed laser modality (MicroPulse, Iridex Corp.) chops a continuous wave laser beam into a series of tiny “packets” repeatedly delivered over a longer period. A 30% duty cycle results in the laser being on 30% of the time and off 70% of the time.
This creates just enough laser energy to be absorbed by pigment granules in cells of the pigmented ciliary epithelium that are being targeted, while preventing thermal build-up and collateral damage to surrounding tissue.
When applied to TCP, this “MicroPulse” strategy results in a much safer procedure that retains the efficacy of a traditional continuous wave TCP procedure.
A new glaucoma laser system (Cyclo G6 Glaucoma Laser System, Iridex Corp.) was recently granted FDA clearance to specifically treat patients diagnosed across a range of glaucoma stages, and features the MicroPulse tissue-sparing technology. My colleagues and I presented data from a retrospective series of 48 eyes of 45 patients with refractory glaucoma treated with MicroPulse TCP (mTCP) with the Cyclo G6 laser and the MicroPulse P3 (Iridex Corp.) device.5
Each patient received retrobulbar anesthesia followed by two 50 to 90 second treatments over the superior and inferior hemispheres. The three and nine o’clock hours were spared. The laser was set for a 31.3% duty cycle, creating 0.5 ms bursts followed by 1.1 ms rests, repeated for 50 to 90 seconds.