Investigating Optical and Neural Causes of Vision Loss

April 3, 2015 updated by: US Department of Veterans Affairs
With the aging of the population, the prevalence of age-related macular degeneration (AMD) eye disease has resulted in a large number of people suffering from central vision loss. In fact, the most prevalent cause of blindness among veterans is AMD. Since the number of elderly veterans is expected to double in the next 10 years, loss of vision due to AMD is also expected to proportionally and considerably escalate. People with impaired vision have difficulty with daily activities, such as, reading, driving, and recognizing faces. The goal of the research project is to provide information on factors that contribute to visual impairment. This knowledge is necessary for the development of innovative approaches that will optimize the benefit of vision rehabilitation techniques, aimed at improving vision, thus allowing our veterans to maintain function and productivity. The findings from the proposed research will benefit our veterans and all aging people.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Withdrawn

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

Vision loss has become a major public health problem due to the growth and aging of the population. Age-related macular degeneration (AMD) is the most common cause of vision loss in people over 50 years of age. In the United States, over 10 million people have AMD and over 1.6 million people age 50 and older have late-stage advanced AMD. It is well established that AMD patients with central vision loss use preferred retinal loci (PRL) which are peripheral retinal areas adjacent to the fovea for performing daily activities, such as reading. However, even in healthy eyes, peripheral vision is limited due to reduced neural sampling density compared to the fovea. Additionally, the function of the peripheral retina can be further reduced in patients, owing to degenerative disease processes. These neural substrate losses are coupled with losses in the quality of the optical image on the retina. Optical imperfections increase with age and off-axis viewing, compared to viewing along the optical axis of the eye. The combination of these factors plays a significant role in reducing visual performance of patients with eccentric fixation. The long term goal of the project is to improve the visual performance of veterans with central vision loss by development of innovative approaches that will optimize the benefit of vision rehabilitation techniques. In the current proposal, optical and neural losses will be assessed in AMD patients with central vision loss using novel techniques. Increased optical losses due to age and viewing off the optical axis of the eye will be established with wavefront analysis technology. Increased neural losses due to retinal dysfunction at PRL will be determined based on measurement of visual acuity with blurred stimuli. Improvement in reading speed will be evaluated, conditional on neural losses at PRL and/or the stability of PRL, after compensating for optical losses with our adaptive optics system. The findings will provide knowledge of PRL function and stability that is beneficial for improving the outcome of available vision rehabilitation methods that train patients to better use their PRLs. Also, customized correction of optical imperfections of the eye for effectively improving visual performance can be developed as an approach for better vision rehabilitation of patients. Optimizing vision rehabilitation of our veterans will allow them to maintain function and productivity.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Illinois
      • Chicago, Illinois, United States, 60612
        • Jesse Brown VA Medical Center, Chicago, IL

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

50 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Normal healthy subjects and patients diagnosed with age-related macular degeneration and central vision loss will participate in the study.

Description

Inclusion Criteria:

Standard inclusion criteria are:

  • qualification for entry into the study based on clinical evaluation,
  • competence to understand and willingness to sign an informed consent form and participate in the study,
  • pupils that dilate to 5 mm or more.

The inclusion criteria for normal subjects will be:

  • corrected visual acuities better than 20/30,
  • intraocular pressure less than 21 mm Hg,
  • no family history of AMD,
  • no history of ophthalmic surgery or neurologic disease,
  • no history of diabetes, glaucoma, or a history of elevated intraocular pressure.

The recruitment will ensure that approximately 40 subjects will fall into each of the three age groups, 50 to 60 years, 61 to 70 years, and 71 years and older. One eye of each subject will be selected at random to be included in the study.

Exclusion Criteria:

  • Ocular opacities that preclude acquiring a clear fundus photograph or refractive errors greater than 4 diopters.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Group 1

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Ocular aberrations
Time Frame: One time only
One time only

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
US Department of Veterans Affairs

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Mahnaz Shahidi, PhD, Jesse Brown VA Medical Center, Chicago, IL

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2014

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 1, 2015

Study Completion (Anticipated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 1, 2015

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 22, 2009

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 23, 2009

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 24, 2009

Study Record Updates

Last Update Posted (Estimate)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 6, 2015

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 3, 2015

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2015

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • C7002-R

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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