During the screening visit, your best corrected visual acuity (the clearest vision you can achieve with glasses or contact lenses) will be measured in both eyes using a standardized eye chart.

Your study eye will be examined using fluorescein angiography (a test where dye is injected into your arm to photograph blood vessels in your eye) and optical coherence tomography (a scanning device that takes detailed images of your retina).

Your central subfield thickness (the thickness of the central part of your retina) will be measured and must be 500 micrometers or less.

Between Week -5 and Week -1, you will receive an injection of aflibercept into your study eye to assess your response to treatment. This medication is given as a single intravitreal injection (an injection directly into the gel-filled space of your eye).

At Week -1, your eye will be examined again to confirm that the thickness of your retina has decreased by at least 15% or that fluid has completely resolved, and that your vision has not decreased by 15 letters or more compared to the screening visit.

On Day 1, you will be randomly assigned to one of two treatment groups. This means you will receive either 4D-150 or aflibercept, but neither you nor your doctor will know which treatment you are receiving.

If assigned to the 4D-150 group, you will receive a single intravitreal injection of 4D-150 at a dose of 3 ×10^10 vector genomes into your study eye.

If assigned to the aflibercept group, you will receive an intravitreal injection of aflibercept at a dose of 2 mg into your study eye.

Following the injection, you will receive difluprednate eye drops to be applied topically (directly onto the surface of your eye) as prescribed by your doctor.

If you were assigned to the aflibercept group, you will receive additional intravitreal injections of aflibercept at a dose of 2 mg every 8 weeks throughout this period.

If you were assigned to the 4D-150 group, you will be monitored at regular visits. You may receive additional aflibercept injections if your doctor determines that your eye condition requires further treatment based on examination findings.

At each visit, your vision will be tested and your retina will be examined using imaging techniques to assess the response to treatment.

At Week 52 (approximately one year after your first treatment), your best corrected visual acuity will be measured to determine the change in your vision compared to the beginning of the trial.

The thickness of your retina will be measured to assess anatomical changes.

The number of additional injections you received after Week 4 will be recorded.

You will continue to attend regular follow-up visits through Week 104 (approximately two years after your first treatment).

If you were assigned to the aflibercept group, you will continue receiving intravitreal injections of aflibercept at a dose of 2 mg every 8 weeks.

If you were assigned to the 4D-150 group, you will continue to be monitored and may receive additional aflibercept injections if needed based on your eye condition.

Your vision and retinal thickness will continue to be assessed at each visit throughout this period.

If you are a sexually active male, you must use a barrier method of contraception (such as a condom) during sexual intercourse for 3 months after Day 1 to prevent transmission of bodily fluids.

During this 3-month period, you should not father a child or donate sperm.