Clinical Trials in 

Vision Research
�

Information for Volunteers 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES 

National Institutes of Health 

National Eye Institute 
Clinical trials in vision research have 

led to new medications, surgeries, and 

methods for disease detection.
Contents 

Clinical Trials in Vision Research 1 

Basics of Clinical Trials 3 

How a Clinical Trial is Conducted 7 

Participating in a Clinical Trial 11 

A Volunteer’s Bill of Rights 17 

Questions to Ask Before Participating 19 

Clinical Trials at NEI 22 
Clinical trials in vision research have 

led to new medications, surgeries, and 

methods for disease detection.
Clinical Trials in Vision Research
�

I

f you or someone you know is thinking about taking 

part in a clinical trial, this booklet may answer some 

of your questions. Clinical trials in vision research 

have led to new medications, surgeries, and methods 

for disease detection that have saved or improved the 

eyesight of millions of people. 

The National Eye Institute (NEI), one of the National 

Institutes of Health (NIH), conducts and sponsors 

clinical trials to discover safe and effective methods for 

preventing, diagnosing, and treating eye disease and 

vision loss. Established in 1968, the NEI is the largest 

sponsor of vision research in the United States. 

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Clinical trials are medical research 

studies in which people volunteer to 

participate.
Basics of Clinical Trials 

What is a clinical trial? 

Clinical trials are medical research studies in which 

people volunteer to participate. A clinical trial is used 

to evaluate the safety and effectiveness of a new 

procedure, medication, or device to prevent, diagnose, 

or treat an eye disease or disorder. 

Generally, medical research begins in laboratories. 

After a treatment shows promise in the laboratory, it is 

tested in a study to determine if it will be beneficial for 

patients. 

A clinical trial could test the effectiveness of a new drug 

for age-related macular degeneration or a new surgical 

technique for cataract removal. 

What are the types of clinical trials? 

The following four types, or phases, of clinical trials 

exist: 

• Phase I clinical trials test a potential new treatment 

in a small number of volunteers to determine the best 

dosage and identify potential side effects. 

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• Phase II clinical trials test a 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. 

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• Phase III and IV clinical trials may include hundreds 

or thousands of volunteers around the country. 

These studies compare a new treatment with existing 

treatments or no treatment to determine if the new 

treatment works better, the same, or not as well. 

Phase III clinical trials are conducted to get the new 

treatment approved by regulatory agencies. Phase 

IV clinical trials are conducted after approval to 

understand more about the treatment. 

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Clinical trials are controlled, meaning that 

researchers compare the effects of a new 

treatment with those of another treatment.
How a Clinical Trial is 

Conducted 

The researcher in charge of a clinical trial is called the 

principal investigator. The person who makes the 

arrangements for your visits and explains how the study 

works is called the clinic coordinator. 

Volunteers for clinical trials must meet certain eligibility 

criteria, which may involve age, type, and stage of a 

particular eye condition, and previous treatment for the 

condition. 

If you are eligible for a clinical trial and you agree to 

participate, you will be asked to sign an informed 

consent. This document explains the main purpose 

of the study, the eligibility criteria, the treatment, the 

possible risks and benefits, your rights as a patient, and 

what researchers expect from you. 

All of the doctors involved in the study follow a detailed 

treatment plan known as the study protocol. The 

protocol ensures that all participants are treated in a 

standard way. 

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Clinical trials are controlled, meaning that researchers 

compare the effects of a new treatment with those 

of another treatment. This is done by dividing study 

participants into groups. If you receive the new 

treatment, you are in the treatment group. If you are 

in the control group, you could receive the standard 

treatment for a particular eye condition. When a 

standard treatment does not exist, you may receive no 

treatment, a placebo, or a sham treatment. 

A placebo may be used in clinical trials that test a 

medication. It is a harmless substance that looks 

like the real medication but has no direct effect on 

an eye condition. A sham treatment may be used 

in clinical trials that test a new surgery or device. A 

sham treatment, like a placebo, is safe and has no 

direct effect on an eye condition. Placebos and sham 

treatments are often used to understand both the 

positive and negative effects of a new treatment. 

Researchers randomly assign participants to the 

treatment and control groups. In most studies, you have 

an equal chance of being assigned to each of the study 

groups. Though the study treatment may be effective 
in some cases, new treatments may have serious side 

effects or may not be effective. During the clinical trial, 

there is no way for you or your doctor to know which 

study group will have the best response to treatment. 

In a nonmasked trial, both you and your doctor will 

know your group assignment. In a masked trial, you 

will not know your group assignment. In a double 

masked trial, neither you nor your doctor will know 

your group assignment. Double masked trials help to 

ensure that the results will not be affected by what you 

or your doctor might think about the treatment. 

How are clinical trials in vision different 

from other clinical trials? 

Eyes are one of many body parts that come in pairs. 

This feature gives researchers some additional options 

when they design the study. If an eye condition affects 

both of your eyes, one eye might be placed in the 

treatment group for a study and the other may be in 

the control group. Generally, the eye that will be treated 

is randomly assigned. 

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The success of a clinical trial often 

depends on learning what happens to 

participants over a long period of time.
Participating in a Clinical Trial 

What is expected of volunteers in a 

clinical trial? 

Participants in a clinical trial are expected to receive eye 

exams and other testing. You may need to take a new 

medication or undergo a new surgical procedure during 

the study. You may also be required to return to the 

medical facility for follow-up examinations. These exams 

help determine how well a treatment is working. Such 

follow-up studies can last for months or even years. 

The success of a clinical trial often depends on learning 

what happens to participants over a long period of 

time. Only participants who continue to return for 

follow-up examinations can provide this important 

long-term information. These exams are essential for 

the success of the study. You should consider this when 

you are deciding whether to participate in the clinical 

trial. The study results will not be valid unless almost 

everyone who enrolls in the trial participates in the 

follow-up exams. 

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What are the benefits of participating? 

Participants in NEI studies are monitored by a team of 

expert doctors, nurses, technicians, and support staff. 

By participating, you may be one of the first people to 

receive a promising new treatment. If the treatment is 

effective, it may improve your vision or prevent an eye 

condition from occurring. 

If you are in the control group and the treatment is 

found to be safe and effective, you may be among the 

first to benefit from the treatment when the study ends. 

All participants in clinical trials contribute to new 

knowledge that may help other people who experience 

similar eye problems. If you have an eye condition that 

runs in your family, your participation may also lead to 

better care for your family members. 

What are the risks of participating? 

Medical professionals have no method for predicting 

if a new treatment will work in a particular person. 

The treatment you receive could cause side effects 

that are serious enough to require medical attention. 
Participants must understand that a new treatment may 

not work better than a standard treatment, may not 

work at all, or may be harmful. 

What if a volunteer’s health changes 

unexpectedly during the study? 

Your health is unpredictable. You could develop a 

serious medical condition during the study that is 

completely unrelated to your vision. If this happens, 

doctors may determine that it is in your best interest to 

leave the study. Your overall health always comes first in 

a clinical trial. 

How is patient safety protected? 

Before a clinical trial begins, researchers must get 

approval from an Institutional Review Board. This 

independent advisory group makes sure that a clinical 

trial is designed to be scientifically correct and to 

protect patient safety. 

During a clinical trial, doctors will closely monitor you 

to see if the treatment is working and to identify any 

side effects. All of these observations are recorded 

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and reviewed. In addition, an independent group of 

experts known as the Data and Safety Monitoring 

Committee carefully monitors every NEI-supported 

trial. This group can recommend that a trial be stopped 

if the risks outweigh the benefits for participants or if 

the new treatment is so effective that it could be used 

by everyone as soon as possible. 

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What are the costs of a clinical trial? 

All medical care provided at the NEI medical facility 

in Bethesda, Md., is free of charge. Clinical trials 

conducted at other locations may involve costs related 

to standard medical care. These may or may not be 

covered by health insurance. You should discuss any 

possible costs with your healthcare provider and 

insurance company before enrolling in a clinical trial. 

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You have the right to know all of the risks 

and benefits of the treatment involved in 

the study.
A Volunteer’s Bill of Rights 

As a participant in a clinical trial, you have the right to: 

• Know all of the risks and benefits of the treatment 

involved in the study. 

• Know how, for how long, and where the researchers 

plan to carry out the study. 

• Know what is expected of you in the study. 

• Know any costs involved for you or your insurance 

company. 

• Be aware of any medical and personal information 

that is shared with other researchers who are directly 

involved with the study. 

• Talk openly with doctors. 

• Ask questions about the study. 

• Leave the study at any time after enrolling. However, 

you should not enroll if you think you may be unable 

to complete the study. 

• Receive any new information about the treatment 

that becomes available during the study. 

• Be informed of your treatment assignment after the 

study is completed. 

• Maintain your privacy even after your participation 

is completed. Your name should not appear in any 

reports based on the study. 

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Talk with your doctors, family members, and 

clinical trial staff to determine whether a 

particular study is the right choice for you. 
Questions to Ask Before 

Participating 

It is important to completely understand the clinical 

trial before volunteering. Talk with your doctors, 

family members, and clinical trial staff to determine 

if a particular study is the right choice for you. Before 

deciding, be sure you know the answers to the 

following questions: 

About the study: 

• What is the purpose of this clinical trial? 

• Why do researchers think the new treatment being 

studied may be better than the standard treatment? 

• What is known about side effects from the 

treatment? 

• What tests and treatment will I receive? 

• Will I need surgery or medications? 

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• Will I be hospitalized? 

• How will the study benefit me? How will it benefit 

others? 

About your health: 

• How might the treatment benefit my eye condition? 

• What are the possible short- and long-term risks and 

side effects of the treatment? 

• What are the chances of any side effects occurring? 

• How will my health be monitored during the study? 

• Who will be in charge of my care? Will I be able to 

see my own doctor? 

About your commitment: 

• Will taking part in the study affect my daily life? 

• How long will the treatment last? 

• How often will I need to return for follow-up exams? 
• What is the total time involved? 

• How much will it cost me to be in the study? 

• How do I feel about taking part in a clinical trial? 

How do my family and friends feel about my 

participation? 

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Clinical Trials at NEI 

The NEI Web site lists the clinical trials that are currently 

recruiting volunteers. This list includes studies taking 

place on the NIH campus in Bethesda, Md., and NEIsupported studies being conducted at clinical centers 

around the country. Eligibility criteria are included for 

each study. 

For more information about enrolling in an NEI clinical 

trial, go to http://www.nei.nih.gov/eyeclinic. 

For more information about the NEI, contact: 

National Eye Institute 

2020 Vision Place 

Bethesda, MD 20892-3655 

nei2020@nei.nih.gov 

301-496-5248 

For more information about clinical trials, visit 

http://www.clinicaltrials.gov. 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES 

National Institutes of Health 

National Eye Institute 

NIH Publication No: 09–4124 

Revised 08/09