Clinical trials play an active role in helping doctors and scientists better understand, treat, and cure diseases. They’re a type of research study performed on willing participants who meet the study’s qualifications, whose goal is to evaluate a type of intervention or treatment—be it behavioral, medical, or surgical—and determine whether it is safe and effective. For people with glaucoma who are interested in participating in a clinical trial, Living Well with Low Vision by Prevent Blindness explains how clinical trials work and how to get involved.*

What is a clinical trial?

Clinical trials are generally conducted in four phases and can take years to complete.

Phase I tests a low dose of the new treatment on a small number of study participants. This phase begins to explore the treatment’s: 

• safety,
• effectiveness, and
• side effects.

If the treatment is found to be sufficiently safe, the study will progress to phase II. 

Phase II tests the treatment on a larger, more diverse group of participants who are living with the disease or condition under study. This phase aims to determine the most effective dosage, application, and frequency of the treatment that also has the fewest and least troublesome side effects to remain safe. 

Phase III involves testing on an even larger, and more diverse, populations. The treatment in question will be used in combination with other medications or interventions. If the U.S. Food and Drug Administration (FDA) finds phase III results satisfactory for both safety and effectiveness, it will approve the new treatment for widespread distribution and use for the purpose(s) defined.

Phase IV of a clinical trial consists of monitoring the effects and outcomes of the treatment after the FDA has approved it. The drug or device has gone into circulation beyond the controlled population of study participants.  

Not all clinical trials are conducted on the same scale or with the same broad focus. For instance, some smaller trials may only test for side effects of a particular drug at specific dosages. These are referred to as “dose-ranging” or “dose-escalation” trials.

Where are clinical trials conducted? 

Clinical trials are conducted at a variety of locations including hospitals, universities, clinics, or at specialty disease centers, such as cancer centers, throughout the U.S. and all over the world. Some clinical trials provide a stipend or partial reimbursement to help pay for travel to the study location.

How do I participate in a clinical trial?

There are several steps involved in joining a clinical trial, which include:

• Finding a relevant trial
• Establishing your eligibility and contacting the trial organizers
• Providing your informed consent

Finding a relevant trial 

A few useful resources for locating available studies include:

• Your healthcare provider
• www.clinicaltrials.gov
• www.centerwatch.com 
• antidote.me 
• Education and advocacy organizations for your particular health condition 

Establishing eligibility and contacting the trial organizers

Each trial has specific eligibility requirements. Read those thoroughly to determine if you are a good potential fit before contacting the organizers of the study. The appropriate contact information will be listed in the recruitment announcement. 

If the organizers agree that you meet their criteria, they will schedule an appointment to meet with you to review the study description and make sure you understand the protocol (specific rules and plan of action). They may also request or require that you undergo a physical exam or other eligibility tests.

Speak with your healthcare provider about the potential risks and benefits of your participation in the trial before joining.

Providing your informed consent

What are you consenting to when you join a clinical trial? In most clinical trials, the organizers will randomly assign you to either:

• An experimental group, which receives the treatment or therapy that is being tested 
• A control group, which receives a standard treatment, a placebo, or no treatment at all 

You have no say in your assignment. In most cases, you will not know to which group you have been assigned.

When all has been explained, and you are confident that you understand the protocol, risks, and potential benefits, the reviewer will ask you to sign an informed consent. You will not be allowed to participate in the study without it.

Will I have to pay to be in the study?

Once the study begins, you are typically not charged for medications or therapies received as part of the trial. You may need to pay for doctor visits before acceptance into the study. You also may have to carry the cost of travel, food, and lodging (depending on the trial location), although some studies do reimburse study-related expenses.

*Living Well with Low Vision by Prevent Blindness. (n.d.). Clinical Trials. https://lowvision.preventblindness.org/clinical-trials/