A study of photodynamic therapy for long-lasting central serous chorioretinopathy

Plain English summary of protocol

Background and study aims
Central serous chorioretinopathy (CSCR) is an eye condition where fluid builds up under the retina, causing blurred or distorted vision. In many cases, the fluid clears up on its own, but in some people it persists for months or years, leading to permanent vision loss. There is currently no proven treatment for chronic CSCR.
Photodynamic therapy (PDT) is a laser treatment that uses a drug called verteporfin to target abnormal areas in the eye. Although PDT is used in some NHS hospitals to treat CSCR, there is limited evidence from clinical trials to show how effective or safe it is.
The PAINT trial will compare PDT using verteporfin with a placebo (dummy) treatment in people with chronic CSCR. The placebo involves the same laser procedure but without the active drug. The study will help determine whether PDT improves vision and reduces fluid under the retina better than placebo.

Who can participate?
Around 140 participants will be recruited from at least 13 hospitals and clinics across the UK. Participants must have visual impairment due to Central Serous Chorioretinopathy (CSCR) of more than 4 months duration.

What does the study involve?
Participants will be randomly assigned to receive either PDT or placebo and followed for 12 months. They will attend clinic visits for eye scans, vision tests, and questionnaires. Some participants may be offered repeat treatment if their condition does not improve. A small blood sample may be collected to explore genetic factors that affect treatment response.
The study is funded by the National Institute for Health and Care Research (NIHR) and managed by the Bristol Trials Centre. It has been designed with input from patients who have experience of CSCR and PDT. Their feedback helped ensure the study is acceptable and practical for participants.
The results will help guide future treatment decisions and may lead to better care for people with chronic CSCR.

What are the possible benefits and risks of participating?
Benefits:
Not provided at time of registration
Risks:
Participation in the PAINT trial may involve some risks and burdens. These are outlined below in plain language, along with steps to minimise them:
Light sensitivity after treatment:
Participants receiving photodynamic therapy (PDT) with verteporfin may become sensitive to light for up to 48 hours. This can cause skin discomfort or sunburn if precautions are not followed. To minimise this risk, participants will be given clear instructions to avoid direct sunlight and bright indoor lighting, wear protective clothing (e.g. long sleeves, sunglasses, hat), and use curtains indoors. A safety bracelet will be provided to alert healthcare professionals in case of emergency.
Temporary blurred vision:
Some participants may experience blurred vision for a few days after treatment. This is expected and usually resolves quickly. Participants will be advised to contact the trial team if their vision worsens or does not improve after four days.
Discomfort from intravenous infusion:
All participants will receive an intravenous infusion (either verteporfin or placebo). This may cause mild discomfort, bruising, or anxiety. Only trained staff will administer the infusion, and participants will be monitored during and after the procedure.
Eye imaging and assessments:
Participants will undergo several eye scans and visual tests (e.g. OCT, FFA, ICGA). These are non-invasive but may be time-consuming and tiring. Visits will be scheduled flexibly, and participants can take breaks during assessments. Optional tests (e.g. microperimetry) will only be performed at sites where available and with participant agreement.
Blood sample for genetic testing (optional):
Participants may be asked to provide a blood sample for future genetic research. This is optional and will not affect participation. Samples will be collected by trained staff, stored securely, and anonymised. No individual results will be returned.
Time commitment and travel:
Participants will attend several clinic visits over 12 months. This may be inconvenient. Travel expenses will be reimbursed, and appointments will be scheduled flexibly. Participants may be offered appointments at alternative sites if needed.
Emotional impact:
Some participants may feel anxious about their diagnosis or treatment. Others may be disappointed if allocated to the placebo group. The trial team will provide clear information and reassurance. All participants will be offered rescue treatment if their vision worsens.
Confidentiality and data security:
Personal and medical data will be collected and stored securely using REDCap. Only authorised staff will have access. Identifiable data will be separated from research data. The risk of data breach is low and mitigated by strict data protection procedures.
Patient and Public Involvement (PPI):
Risks and burdens have been reviewed with patients who have experience of CSCR and PDT. Their feedback helped shape the study design, including flexible visit windows and clear communication materials. They felt the risks were acceptable and the trial was well designed.
All risks and burdens are described in the Participant Information Sheet in clear language. The trial team will monitor safety throughout the study and make changes if needed to protect participants.

Where is the study run from?
University of Bristol - Bristol Trials Centre (UK)

When is the study starting and how long is it expected to run for?
January 2026 to February 2029

Who is funding the study?
National Institute for Health and Care Research (NIHR) (UK).

Who is the main contact?
paint-trial@bristol.ac.uk

Contact information

Study information

Eligibility

Locations

Countries of recruitment

• United Kingdom
• England
• Northern Ireland

Study participating centres

Results and Publications

Editorial Notes

10/04/2026: Internal review.
22/12/2025: Trial's existence confirmed by NHS HRA.