Safety in Vision Research

It is important to know your rights when participating in research and to be well informed about the research that is being conducted. We in Fighting Blindness advise that people always consult an ophthalmologist before participating in a clinical trial. We also cannot stress enough that nobody should ever have to pay to participate in a clinical trial. Legitimate trials do not charge people to participate.

In vision research, if a condition affects both eyes, a clinical trial will often investigate the treatment in one eye first, using the other eye as a placebo or comparison.

Clinical trials are medical research studies in which people volunteer to participate. Before a potential treatment can be administered to humans as part of Phase I (first-in-human) clinical trials, it must undergo rigorous safety and efficacy testing in non-clinical studies. Non-clinical testing, also called pre-clinical testing is conducted at a stage of medicines development that uses animals and/or cells or tissues. It does not involve testing in humans. The main goal of non-clinical tests is to determine the safety of a medicine. After preclinical testing, researchers review their findings and decide whether the drug should be tested in people in a clinical trial.

What are the different phases of a clinical trial?

Phase 1 Trial

These are the earliest trials in the life of a new drug or treatment. They are usually small trials, recruiting anything up to about 30 people. Phase one trials are undertaken to determine the safety of a potential treatment. People recruited to phase one trials often have advanced eye disease. This work has to be completed first, as safety is the most important issue to resolve before wider testing of the potential new treatment.

Phase 2 Trial

This type of trial tests the potential new treatment in a larger number of volunteers to learn more about how the body responds to the treatment, the optimal dose of the treatment and how the treatment affects a certain eye condition. If the results of phase two trials show that a new treatment may be as good as existing treatment or better, they move to Phase three. Determining the safety of the drug is a large component of phase two testing and sometimes phase one and phase two trials are run at the same time.

Phase 3 Trial

Treatments only move into a phase three clinical trial if phases one and two suggest that a substance might actually be useful and safe in ways that patients would regard as important. Phase three trials are usually much larger than phase one or two, sometimes involving hundreds or thousands of patients in many different settings. Phase three trials are usually randomised. This means the researchers put the people taking part into two or more groups at random. One group gets the new treatment and the other the standard treatment or a placebo (non-active) treatment.

Phase 4 Trial

Phase four trials are performed after a drug has been shown to work and has been granted a license. They are performed in order to understand more about the treatment, by evaluating its safety and effectiveness in larger numbers of patients subgroups of patients, and to compare and/or combine it with other available treatments. The time from a phase one to a phase four trial can take many years.

Enrolling in clinical trials

Before a participant can enrol in a clinical trial, they must be recruited, screened, and give their informed consent. The process of enrolling in clinical trials is carefully regulated in order to protect the participants and maintain the clinical trial’s validity.

The informed consent process is one of the key aspects of protecting research participants. Informed consent is a person’s voluntary agreement, based on an understanding of the relevant information, to participate in research or a clinical trial, or to undergo a particular medical intervention.

Before any research may be carried out, participants must be informed about all aspects of the study and/or intervention, including the aims, methods, anticipated benefits, and potential risks. Participants must also be made aware that they can withdraw from the research at any stage without any negative consequences to their ongoing care or treatment. This information must be given in an accessible and understandable way and individuals should be given the opportunity to ask questions about the research.

Informed consent is usually documented in writing with a signed and dated consent form. However, informed consent should be an ongoing process throughout a study, and researchers should ensure that participants are made aware of any new information which might influence their decision about whether to take part or not.

Compensation in Clinical Trials

Although not always a standard, in many clinical trials participants receive some form of compensation for their participation. Reimbursement expenses refer to any expenses incurred in relation to participation in a clinical trial. This may take the form the reimbursement of travel expenses, food or food vouchers, or other services. Reimbursement is payable to all eligible participants or their legally designated representatives. This is documented before a clinical trial begins.

The National Eye Institute (NEI) in the US have producded a booklet called ‘Clinical Trials in Vision Research’ which can be downloaded from their website here.


Some of the content above has been modified from that contained on the EUPATI Toolbox,, which is available to use under Creative Commons License.