Although aCSC is a self-limiting disease, some experts suggest observation for aCSC within 3 months [11]. However, 30–50% of aCSC will recur or convert to chronic CSC, and repeated attacks will cause irreversible damage, scarring, CNC, etc., which will seriously affect the patients' vision and visual quality, therefore, most experts advocate active treatment [12]. This study is aimed at aCSC within 500um from the central fovea, which is the CL contraindication area, limited by the expensive cost of PDT and the deficiency of photosensitizer verteporfin, with reference to 577nm SML retinal edema region full coverage for the treatment of venous occlusion and diabetic macular edema [13], we optimized the treatment of aCSC with 577nm SML to fully cover the neuroepithelial and/or pigment epithelium detachment area.
The data from the 24 eyes examined in this study, the scope of photocoagulation was not limited to sealing the leakage point. On the basis of a large number of studies on 577nm SML in the care of macular edema originated by RVO and DR, and the hypothesis and practice of good treatment results [14], photocoagulation leakage was attempted. The areas other than the point include the borders of healthy retina and neuroepithelium, pigment epithelium detachment and all edema areas. The 577nm SML consists of a sequence of persistent extremely-short laser pulses with a 5% duty series of events and a 200ms working time, which is equivalent to 10ms continuous action and 190ms rest, during which the retina cools down. This mode avoids sublethal cellular thermal effects of continuous prolonged exposure to heat, and 577nm SML not only seals the leakage point and prevents leakage, but also stimulates the RPE activity in the non-leak point area, restores the absorption function of RPE cells, and accelerates the absorption of SRF, not just the thermal coagulation of RPE [15]. Compared with the 577nm SML, CL or PDT, the method of 577nm SML for the full coverage of the detachment area in the treatment of aCSC was compared with the complete absorption of SRF 4–6 weeks after the 577nm SML, CL or PDT simple leakage point sealing treatment. The former SRF absorption time is shorter and visual function recovery is faster. From the statistical results of BCVA and CRT, 1w, 1m, and 3m after treatment, the value of them were different with the baseline (p < 0.01). In addition, the data were comparable between 1m and 3m. It shows that the 577nm subthreshold micropulse has obvious effect on aCSC. One month after treatment, except for 3 patients with scattered high-reflection metabolite deposition between the inner and outer retinas, the anatomical structures of the remaining patients returned to normal, which also shows that the program is safe and reliable, and can be reused for patients who fail to absorb it.
Power titration is critical for 577nm SML treatment, too light will not achieve therapeutic effect, and too heavy may cause damage, usually outside the vascular arcade[16–17]. In single-point mode, 300mw starts titration until the first-level spot, at which point the power is the threshold, and then treated with 50% threshold power [18]. This study was done by the same fundus doctor. The therapeutic capacity after titration in 24 patients was 400-450mw. The treatment effect was obvious, and no obvious complications and injuries occurred.
The pathogenesis of aCSC involves choroidal thickening and hyperosmolarity, as well as increased hydrostatic pressure, leading to RPE detachment. Additionally, the disruption of the outer blood-retinal barrier also leads to liquid infiltration into the subretinal space, and active of CSC [19]. In this study, Statistically significant reduction in CVI 3 months after treatment, indicating that 577nm SML treatment can help improve choroidal hyperperfusion, reduce hydrostatic pressure, and prevent leakage, which is the same as PDT, can be resolved mechanistically in the treatment of aCSC. However, the sample size is small in the present study, a large number of clinical cases are still needed for confirmation.
In conclusion, 577 nm SML can improve choroidal hyperperfusion, lessen fluid leakage, activate RPE, accelerate serous absorption, and its pulsed treatment will not cause damage to the retina. Compared with CL, 577nm SMPL has wider indications, is more economical than PDT, and overcomes the dilemma of the lack of photosensitizer verteporfin.577 nm SML treatment of aCSC is a safe, effective, economical method with few side effects. On this basis, full coverage of the serous detachment area beyond the leakage point can accelerate the absorption of SRF. 577nm SML is the best choice for the treatment of aCSCs within 500 µm from the fovea. The full coverage of the serous exudate area, including the fovea, for the treatment of aCSC is safe and feasible, and is worthy of promotion. Based on the action principle of 577nm SML, the method was further applied to CSCs with insignificant leakage points and multiple leakage points.