Abstract
Purpose :
The micropulse mode of serial lasers with short-pulse duration and duty cycle allows one to exert selective impact on the retinal pigment epithelium (RPE). However, there are no standard micropulse modes for treatment, it is difficult to control the level of retinal damage, and individual pre-testing is required. In this study, the development of the Selective Micropulse Individual Retinal Therapy (SMIRT) with a low level of retinal damage and the assessment of the therapeutic effect of CSC (central serous chorioretinopathy) without preliminary testing are addressed.
Methods :
This study has been conducted on 73 patients with acute CSC, transparent optical media, aged 30 to 65, with type 1-4 on the Fitzpatrick scale (FS). The testing of the micropulse mode (50 µs, 2.4%, 10 ms, 100 µm, 0.4-1.9 W) was performed in 33 patients with 1584 spots analyzed using the autofluorescence (AF) method (488 nm). Another 40 patients were divided into 4 equal groups (10 eyes). In groups 1-3, CSC was treated in the same micropulse mode with the predicted power for the ED of the RPE damage according to AF data of 50%, 70%, and 90%, respectively. The 4th was the control group with no treatment. The testing and treatment were performed with a Navilas577s laser system. Computer simulation was built with the Arrhenius integral to assess the heating and protein denaturation of the RPE and adjacent structures. The Fisher's exact test was used for statistical analysis.
Results :
A logistic regression function EDlevel with 3 parameters such as power, age, and FS was constructed based on the AF results for 33 patients. The reverse function was used to predict the required power based on the individual properties according to the chosen ED level. According to computer simulation, for the modes used in groups 1-3, harmful damage to retina and choroid was 35%, 37% and 49% of the damage to the RPE, respectively. Three months later, in groups 1-3 complete resorption of subretinal fluid was observed in 5 (P<0.35), 8 (P<0.023) and 10 eyes (P<0.0008) out of 10, respectively.
Conclusions :
In the developed SMIRT, the required power is selected without prior testing, based on the age and FS of the patient. The SMIRT has shown efficacy in the treatment of CSC.
This is a 2021 ARVO Annual Meeting abstract.