From the Guidelines
The interval between repeating photodynamic therapy sessions for central serous chorioretinopathy should be at least 3 months, as evidenced by the study by van Dijk et al. in 2018, which reported complete resolution of subretinal fluid in 67% of patients after 7-8 months following half-dose PDT 1.
Key Considerations
When determining the optimal interval for repeating photodynamic therapy (PDT) sessions, several factors must be considered, including the patient's response to initial treatment, the presence of any adverse effects, and the natural history of the disease.
- The study by van Dijk et al. in 2018 found that half-dose PDT resulted in complete resolution of subretinal fluid in 51% of patients after 6-8 weeks and 67% after 7-8 months 1.
- Another study by Fujita et al. in 2015 reported complete resolution of subretinal fluid in 89% of patients at 12 months after treatment with half-dose PDT 1.
- The long-term efficacy of half-dose PDT is generally favorable, with subretinal fluid resolution rates of 91% and 81% at a mean follow-up of 19 and 50 months, respectively 1.
Clinical Implications
The decision to repeat PDT sessions should be based on individual patient factors, including the severity of the disease, the presence of any complications, and the patient's overall health status.
- Patients who do not achieve complete subretinal fluid resolution after reduced-setting PDT may experience a smaller reduction in central retinal thickness compared to patients who achieved complete resolution 1.
- Recurrent subretinal fluid after initial complete resolution following ICGA-guided half-dose PDT for central serous chorioretinopathy occurred in 13% of patients measured at a mean follow-up of 19 months and in 18% of patients measured at a mean follow-up of 50 months 1.
Treatment Approach
A treatment approach that takes into account the individual patient's response to initial treatment and the natural history of the disease is essential to optimize outcomes and minimize adverse effects.
- The use of half-dose PDT has been shown to be effective in reducing subretinal fluid and improving visual acuity in patients with central serous chorioretinopathy 1.
- The timing of repeat PDT sessions should be determined by the healthcare provider based on the patient's particular condition, the area being treated, and how the tissue responded to the previous treatment.
From the FDA Drug Label
In all trials, the lesions that were not completely cleared 12 weeks after the initial treatment were treated a second time with an identical regimen. The time between repeating photodynamic therapy is 12 weeks.
- This is based on the information from the clinical trials where lesions that were not completely cleared after the initial treatment were treated again after 12 weeks. 2
From the Research
Repeating Photodynamic Therapy
- The interval between repeating photodynamic therapy sessions is not explicitly stated in the provided studies, but we can infer some information from the study protocols and results.
- In the study by 3, patients were followed up for 3 months after a single treatment, and fluorescein leakage from CNV reappeared by 4 to 12 weeks after treatment in almost all cases.
- The study by 4 mentions that patients returned for follow-up every 3 months, and additional courses of treatment were recommended if any fluorescein leakage from CNV was identified.
- This suggests that photodynamic therapy sessions can be repeated every 3 months, but the exact interval may depend on the individual patient's response to treatment and the presence of fluorescein leakage from CNV.
- The study by 5 also mentions that patients were treated with verteporfin and followed up for one year, but it does not provide information on the interval between repeated treatments.
Factors Influencing Re-treatment Interval
- The decision to re-treat with photodynamic therapy may depend on several factors, including:
- The presence of fluorescein leakage from CNV
- The size and composition of the CNV lesion
- The patient's visual acuity and response to previous treatment
- The presence of any adverse events or complications
- The studies by 3, 4, and 5 provide some guidance on these factors, but more research is needed to determine the optimal re-treatment interval and criteria for repeating photodynamic therapy.