Photostimulation promising for central serous chorioretinopathy

Take-home message: A pilot study suggests that using subthreshold photostimulation with a 577-nm PASCAL yellow laser is an effective and safe option for central serous chorioretinopathy.

By Michelle Dalton, ELS; Reviewed by Juan D. Arias, MD

Bucaramanga, Colombia-Central serous chorioretinopathy (CSC) is a fairly common retinal disorder that has been associated with “type A” personalities. The primary complaints upon presentation are usually limited to distorted vision, decreased color sensation, or a loss of central vision.

Although the disorder tends to present more in Caucasians, Hispanics, and Asians than in people of other ethnicities, recurrence seems to occur more in Caucasians. Associated causes have ranged from pregnancy to tobacco use, said Juan D. Arias, MD.

A pilot study¹ suggests the subthreshold photostimulation with a 577-nm PASCAL yellow laser is an effective and safe option in the management of CSC, and can provide both a visual and anatomic improvement.

“Even with the advancement of imaging techniques and the identification of multiple risk factors, the etiology and the pathophysiology of CSC still remain unclear,” said Dr. Arias, in practice at Foscal Internacional, Bucaramanga, Colombia.

He added that most current theories emphasize the role of the choroidal vascular hyperpermeability (possibly as a result of stasis, ischemia, or inflammation) and the functional or structural defect in the fluid-pumping capabilities of the retinal pigment epithelium (RPE) as the cause of the disease.^2-4

“Plus, chronic CSC may have a slightly different pathophysiology of acute CSC,” Dr. Arias said.

Liew et al. showed that in the chronic type, the RPE dysfunction is diffuse and widespread without evident detachment in most cases. In acute CSC, the RPE dysfunction occurs at multiple foci and the detachment is evident, he noted.

Further, in CSC, the outer blood-retinal-barrier breakdown can result in retinal or RPE detachment.

“While there are several treatment options, there is no set ‘gold standard’ of care for CSC,” he said, but noted the literature describes numerous procedures, including laser photocoagulation, micropulse diode laser photocoagulation, transpupillary thermotherapy (TTT), photodynamic therapy (PDT), and intravitreal application of anti-vascular endothelial growth factor.^{2, 5-6}

However, with both TTT and PDT, complications have been reported and the recurrence rate “remains controversial.” ¹

Clinicians are, therefore, left without guidance on when (or whether) to treat, and ‒ more importantly ‒ how best to treat to reduce the likelihood of recurrence.

An advantage of the PASCAL laser, the study authors said, is that it can “optimize the therapeutic effect with minimal damage to the retinal tissue.”

Also, because the laser does not induce tissue damage (unlike conventional laser), there is no cumulative scarring, he noted.

Study details

Dr. Arias and colleagues retrospectively studied 11 eyes of 10 Hispanic patients with CSC of more than 3 months’ duration who had been treated with PASCAL yellow 577 nm laser (Topcon Medical Laser Systems). Patient age ranged from 27 to 64 years of age, with a mean of 47 years.

CSC is typically a self-limited process with spontaneous resolution within 1-4 months and resolves without substantial adverse visual outcomes, but “some situations require treatment,” Dr. Arias said, including persistent macular subretinal fluid, and chronic or recurrent cases.

“Our thought process behind using PASCAL as a means of treating people with chronic CSCR was try to stimulate the RPE cells for reactivate the fluid-pumping capabilities,” he said.

With a mean follow-up of 16 weeks, all eyes responded to treatment, the study authors said. Central macular thickness was almost halved ‒ from a mean 410 μm to 218.82 μm; there was no evidence of RPE or retinal damage after imaging by both spectral-domain optical coherence tomography and fundus fluorescein angiography.

Finally, visual acuity improved significantly, from a mean of 0.8 logMAR to 0.15 logMAR. There were neither recurrences nor any adverse event reported.

The group noted the study was not without limitations, among them its small sample size and lack of a control group, a short follow-up period, and an absence of procedure guidelines to unify the laser settings across the patient population.

Clinical relevance

Dr. Arias stressed the key inclusion factor in the group’s analysis was the duration of disease, with “the most important exclusion criteria could be any other secondary cause of subretinal fluid that needs to be ruled out (drugs, choroidal neovascularization, choroidal tumors, etc.),” Dr. Arias said.

While some studies have demonstrated laser photocoagulation decreases recovery time, the PASCAL also has been previously shown to demonstrate the “same safety and efficacy as conventional laser,” Dr. Arias said.

In conclusion, the results of this pilot study “allow us to believe that the subthreshold photostimulation with PASCAL yellow laser is an effective and safe option in the management of CSC with clinical and statistically significant improvement in visual acuity and central macular thickness,” he added.

The study authors recommended a randomized, controlled study be undertaken before a standard treatment protocol can be suggested.

References

• Arias JD, Galvis V, Barrera R, et al. Photostimulation subthreshold Pascal laser in the treatment of central serous chorioretinopathy pilot study. Poster presented at: American Society of Retina Specialists; July 11-14, 2015:Vienna, Austria.

• Nicholson B, Noble J, Forooghian F, Meyerle C. Central serous chorioretinopathy: update on pathophysiology and treatment. Surv Ophthalmol. 2013;58:103-126.

• Liew G, Quin G, Gillies M, Fraser-Bell S. Central serous chorioretinopathy: a review of epidemiology and pathophysiology. Clin Experiment Ophthalmol. 2013;41:201-214.

• Liegl R, Ulbig MW. Central serous chorioretinopathy. Ophthalmologica. 2014;232:65-76.

• Quin G, Liew G, Ho IV, Gillies M, Fraser-Bell S. Diagnosis and interventions for central serous chorioretinopathy: review and update. Clin Experiment Ophthalmol. 2013;41:187-200.

• Abouammoh MA. Advances in the treatment of central serous chorioretinopathy. Saudi J Ophthalmol. 2015. Epub ahead of print.

Juan D. Arias, MD

P: 057 7 679-7979, ext. 8210

This article was adapted from Dr. Arias’ presentation at the 2015 meeting of the American Society of Retina Specialists.