Clinical trials help researchers try out new ways to prevent, treat, and test for eye diseases. If you’re thinking of joining a clinical trial, find out about the different types of trials, the benefits and risks, and what to expect when you participate.
What are clinical trials for?
Researchers use clinical trials to try out all kinds of new ways to prevent, treat, and test for diseases, including:
New procedures, like surgeries
New ways to diagnose a disease
New ways to prevent a disease, like vaccines or special diets
Trials make sure a new treatment, test, or type of preventive care is safe and effective before the Food and Drug Administration (FDA) approves it for regular use.
What are the types of clinical trials?
There are 4 types of clinical trials, called phases. Most new treatments and tests go through 3 phases of clinical trials before the FDA approves them.
Phase I clinical trials test a new treatment in a small group of people to see if it’s safe and if it causes any side effects.
Phase II clinical trials test the treatment in a larger group to see if it works (if it’s an effective way to find, treat, or prevent the disease).
Phase III clinical trials test the treatment in a very large group to see if it works better than what doctors are already using. Treatments need to pass phase III trials to be approved by the FDA.
Phase IV clinical trials help researchers keep learning more about a treatment after it is approved by the FDA.
What happens during a clinical trial?
First, researchers find a group of volunteers who meet the trial’s eligibility criteria. For example, a trial might need volunteers who are a certain age or have a certain eye condition.
Then the volunteers sign a document called an informed consent. It explains the details of the trial and makes sure that volunteers understand the risks and agree to all the rules.
Researchers divide the volunteers into 2 groups:
The treatment group gets the new treatment, test, or preventive care
The control group gets either the standard treatment that doctors already use, or a placebo (a fake treatment that is harmless, but doesn’t work)
When possible, researchers make the trial a double-blind trial. This means that the volunteers don’t know whether they are in the treatment or control group, and neither do the researchers. That way, the results won’t be affected by what the volunteers or researchers think or feel about the treatment.
Depending on the trial, volunteers may need to do different things, like take pills or get eye exams. Volunteers usually need to come back for follow-up visits over several months or years, so researchers can see how the treatment, test, or preventive care works over time.
What are the benefits of joining a clinical trial?
By joining a clinical trial, you can be one of the first people to get a new treatment. If the treatment works, it could make your vision clearer, help treat your eye disease, or help prevent other people from getting your eye disease.
You can also help improve care for countless people in the future. If you have an eye condition that runs in your family, the trial could help find better treatments for your family members.
What are the risks of joining a clinical trial?
Because the treatment, test, or preventive care in a clinical trial is new, researchers don’t know exactly what the risks are. The treatment itself may harm you, or you may get serious side effects.
A team of doctors, nurses, and support staff will give you check-ups to find any side effects and make sure you are healthy enough to stay in the trial.
An independent group of experts will also monitor the trial. If the experts find that the risks of the new treatment outweigh the benefits, they can stop the trial right away. For example, if volunteers get severe and unexpected side effects, the committee may recommend stopping the trial.
What if I want to leave a clinical trial?
Volunteers have the right to leave a trial at any time, for any reason. But if too many people leave a trial, the researchers may not be able to get any results — so it’s important to only join a clinical trial if you think you’ll be able to stay in it until the end.
If you get serious side effects or develop a new health problem during the trial, the researchers may recommend that you leave the trial. Your health always comes first.
What does it cost to join a clinical trial?
Volunteers can join clinical trials at the NEI Eye Clinic in Bethesda, MD for free. Trials at other locations may have costs for volunteers. Before you join a trial, ask the trial staff about costs — and check with your health insurance company to see if your plan will cover some of the costs.
What rights do volunteers have?
People who volunteer to participate in clinical trials have the right to:
Ask questions about the trial
Leave the trial at any time
Keep their medical information private and stay anonymous in reports about the trial
Volunteers also have the right to know things about the trial, including:
Risks, benefits, and costs of the trial
What they will need to do during the trial
Where the trial will happen and how long it will last
How researchers will use volunteers’ private medical information
Any new information about the treatment that researchers find during the trial
After the trial is over, volunteers also have the right to know whether they were in the treatment group or the control group.
How do I know if a clinical trial is right for me?
Joining a clinical trial is a big decision. Talk with your doctor about the risks and benefits. Together, you can decide if a clinical trial is right for you.
It’s also important to ask questions and make sure you understand what’s expected of you before you volunteer.
Clinical Trials in Vision Research: Information for Volunteers
If you're thinking about taking part in a clinical trial, this Clinical Trials in Vision Research booklet will help answer your questions. This booklet has information about clinical trials at NEI and questions to ask before participating in a trial.
Download the Clinical Trials booklet: