Blog: MicroPulse laser is an effective tool in the battle against CSR

Editor's note: The views expressed in this blog are those of their respective contributor and do not represent the views of Ophthalmology Times® or MJH Life Sciences®

Most central serous retinopathy (CSR) cases will spontaneously resolve, but consequences can be severe for those who develop a chronic condition. There is potential for progressive retinal pigment epithelium atrophy and permanent visual loss.

In the past, my preferred treatment modality for CSR has been photodynamic therapy (PDT). PDT is an effective treatment for CSR, but there are some difficulties associated with it. Verteporfin, the intravenous photosensitizer used to perform PDT, is an expensive medication that is often denied by insurance companies with the excuse that it is an experimental treatment only approved for exudative macular degeneration. In addition, clinic flow is somewhat disrupted by PDT cases due to the need for the intravenous infusion. Focal continuous wave laser therapy, though an option for treating pinpoint leaks outside of the fovea, is not something I would use for diffuse leaks or those very close to the center of the fovea.Oral treatment with eplerenone and similar medications in my opinion provides a marginal response, if any, and I have stopped recommending it for CSR.

Over the past couple of years, I have increasingly been using MicroPulse laser for CSR. MicroPulse produces similar responses to PDT, but does not require an intravenous photosensitizing medication.

MicroPulse differs from continuous-wave in that it divides the laser beam into microsecond bursts that are interspersed with longer resting intervals. This allows the relaxation of energy that prevents thermal buildup and tissue necrosis.

MicroPulse has been shown to produce visual rehabilitation and reduce the chances of CSR becoming chronic.¹ Studies have also demonstrated a reduction of fluid in CSR patients treated with MicroPulse laser.^2,3

In my experience, insurance coverage for MicroPulse has not been a problem. Not only does the treatment not require the purchase and inventory management of verteporfin, but the laser treatments can be performed during a busy clinic session, since patient flow is not disrupted by an intravenous infusion. In addition, I like the convenience of having MicroPulse laser on hand and ready to use at any time. I have found the treatment to be effective and convenient, and my patients have been pleased with the ease of the procedure.

In practice

My first course of action with CSR is to make sure I have the correct diagnosis because many pathologies can be similar to CSR, specifically polypoidal choroidal vasculopathy and pachychoroid neovasculopathy. Patients with these conditions might benefit from anti-VEGF injections.

When I am confident that I am dealing with CSR, I will first observe, since many patients get better without treatment. I want to determine that the patient does not get better spontaneously over the course of two or three months, particularly those patients with focal leaks.

Before performing MicroPulse laser, I do a fluorescein angiography, although an indocyanine green angiography may be necessary in patients with chronic multifocal leaks with significant disruption of the retinal pigment epithelium.

I use an IQ 577 Laser (Iridex) with a 5% duty cycle and a duration of 100 ms. I titrate the power before performing the procedure and usually end up with a power setting between 500 mW and 700 mW.

Spots should be confluent or nearly confluent. I use a hundred-micron spot size and a three-by-three grid. Patients tend to move during treatment, so I like the smaller grid.

I specifically treat the areas of leakage and disregard the location of the fluid. When treating CSR, I am trying to fill a leak.

I have the patient return in six weeks for a follow-up visit, and I will continue to see them at six-week intervals until I ensure they are improving. If I see a partial response, but I haven’t seen satisfactory resolution of subretinal fluid and improvement in the pigment epithelial detachment, I may retreat after a few months.

Unfortunately, there is no cure for CSR. However, because MicroPulse does not cause lethal damage to the retina architecture, it can be performed and repeated without great concern for adverse effects. Patients, particularly those with chronic problems who have not been adequately treated, love having something that can improve their vision.

References

1. Arora S, Sridharan P, Arora T, Chhabra M, Ghosh B. Subthreshold diode micropulse laser versus observation in acute central serous chorioretinopathy. Clin Exp Optom. 2019;102(1):79-85. doi:10.1111/cxo.12818

2. Luttrull JK. Low-intensity / high-density subthreshold diode micropulse laser (SDM) for central serous chorioretinopathy. Retina. 2016 Sep; 36 (9):1658-63

3. Piasecka K, Gozdek P, Maroszyński M, Odrobina D. Comparison of 532 nm Micropulse Green Laser versus Continuous-Wave 532 nm Green Laser in Chronic Central Serous Chorioretinopathy: Long-Term Follow-Up. JOphthalmol. 2020;2020:4604567. doi:10.1155/2020/4604567