Evaluation of the Safety and Efficacy of Selective Retina Therapy Laser Treatment in Patients with Central Serous Chorioretinopathy

Abstract

Purpose: To assess the safety and efficacy of selective retina therapy (SRT) using a Q-switched neodymium-doped yttrium lithium fluoride laser with feedback systems in patients with idiopathic central serous chorioretinopathy (CSC).

Methods: This randomized clinical trial enrolled patients having at least 3-month symptom of CSC. From month 3 visit, all subjects in both groups were eligible for SRT retreatment if they showed persistent or recurrent subretinal fluid (SRF). The primary outcome was complete resolution of SRF by optical coherence tomography at 3 months after treatment. The secondary outcomes were changes in SRF, central macular thickness (CMT) and best-corrected visual acuity at the 1-, 3-, and 6-month examinations.

Results: Sixty-eight CSC patients were included (SRT, 31; control, 37). After 1 and 3 months, complete resolution of SRF was achieved in 25.8% and 54.8% of SRT group and 17.6% and 35.1% of controls. The differences were not statistically significant (p = 0.424 and p = 0.142, respectively). However, mixed model for repeated measures analyses showed that the reduction of SRF and CMT were observed earlier in SRT group than in the sham group (least squares mean difference, -59.7 µm; 95% confidence interval, -98.2 to -21.2; p = 0.0029; least squares mean difference -67.0 µm; 95% confidence interval, -104.8 to -29.2; p = 0.0007, respectively). Significant reduction of SRF (≥50% reduction from baseline) was more frequently observed in SRT group (80.6%) than the sham group (44.1%) at month 1 (p = 0.007). Early reduction of SRF and CMT was more abundant in SRT group with symptom duration less than 6 months. Treatment related serious adverse events were not observed.

Conclusions: SRT using a Q-switched neodymium-doped yttrium lithium fluoride laser with feedback system was safe in this trial and effective for early resolution of SRF in the CSC patients. Early intervention with SRT can be a safe alternative for patients with acute symptomatic CSC.

Keywords: Central serous chorioretinopathy; Clinical trial; Laser treatment; Subthreshold micropulse laser.

Fig. 1

Illustration of selective retina therapy test exposure to determine laser energy was determined by irradiation in the upper or lower vessel arcade outside the treatment area until the proper energy display is titrated using the optoacoustic and reflectometry feedback systems. (A) Multiple irradiations were performed around a leakage. (B) Blue arrow indicates leakage determined using fluorescein angiography (FAG) and the yellow dots indicate laser irradiated spots.

Fig. 2

Representative case of selective retina therapy (SRT) arm (subject 04–19). (A) A 54-year-old man with a 49-week history of subretinal fluid (SRF) in the left eye. Best-corrected visual acuity of the left eye was 20 / 25 at baseline. Black arrowhead indicates the line where OCT scan was performed. Left picture is infrared reflectance image and white line indicated by black arrowhead means location where optical coherence tomography (OCT) scan was performed. SRF with flat pigment epithelial detachment (white arrow) was observed at baseline by OCT. The height of SRF was 137.5 μm at the baseline. (B) SRF was markedly decreased and a pigment epithelial detachment resolved at 1 month after SRT treatment. Complete resolution of SRF was shown on OCT up to 6 months after SRT treatment. (C) 3, (D) 4, (E) 5, and (F) 6 months, respectively. There was no notable treatment-related retinal pigment epithelial damage.

Fig. 3

Representative case of control arm (subject 08-07). A 50-year-old man with a 48-week history of subretinal fluid (SRF) in the right eye. Best-corrected visual acuity in the right eye was 20 / 25 at baseline. SRF was observed at baseline by optical coherence tomography. (A) The height of SRF was 122.5 μm at the baseline. Black arrowhead indicates the line where OCT scan was performed. (B) The height of SRF was 71.5 μm after one month from baseline. (C) The SRF was not resolved naturally for 3 months, when the patient was treated by the selective retina therapy (SRT) laser system. (D) At month 4, 1 month following SRT treatment, the height of SRF decreased to 63 μm. (E,F) SRF was completely resolved two months following SRT treatment and it was maintained at the month 6 study exit visit, that is three months following treatment. There was no observable treatment-related retinal pigment epithelial damage.

Fig. 4

Peak height of subretinal fluid (SRF) measured by optical coherence tomography. Peak SRF height was significantly higher in selective retina therapy (SRT) group than in control group at 1 month after treatment. Error bars indicate 95% confidence interval. ^*p < 0.05.