Are There Changes in the Nerve Fiber Layer (NFL) After Lowering of Eye Pressure?

March 13, 2018 updated by: George L. Spaeth MD, Wills Eye

Reversible Structural and Functional Changes After Intraocular Pressure Reduction in Patients With Glaucoma

The aim of this study was to evaluate structural and functional improvement after lowering intraocular pressure (IOP) in patients with glaucoma using Spectral Domain Optical Coherence Tomography (SD-OCT), Visual Field (VF) testing, and Visual Evoked Potential (VEP).

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Glaucoma exhibits characteristic changes to the optic nerve in the back of the eye. The optic nerve is formed when fibers that overlay the retina come together. This layer is called the retinal nerve fiber layer (RNFL).

Optical Coherence Tomography (OCT) is a machine that scans eyes and has the capability of measuring thickness of various layers in the retina and RNFL. This provides important anatomical information.

VEP (visual evoked potential) is an imaging system that measures electrical signals from the eye to the brain by using electrodes placed on the forehead and back of head. This is similar in principal to an electrocardiogram of the heart.

Visual field testing is done to evaluate the extent of side vision loss caused by various diseases of the eye, including glaucoma. This testing is performed as you stare at a small light directly in front of your eye while lights flash one at a time in every direction on a screen surrounding the central light. You push a button each time you see a flash out of the corner of your eye.

Lowering intraocular pressure (IOP) in the eye has been shown to result in reversal of glaucoma changes of the optic nerve in some patients. It has also been suggested that improvement in function (visual field) has been associated with improved optic nerve appearance.

This study seeks to provide evidence for reversal of disc appearance and visual function following IOP lowering interventions.

Study Type

Observational

Enrollment (Actual)

61

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

Ages Eligible for Study

18 years to 90 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Glaucoma patients with intraocular pressure (IOP) between 22 and 32 millimeters of mercury (mm HG); greater than 32 mm HG; and with stable IOPs (control group).

Description

Inclusion Criteria:

  • All patients with glaucoma (primary open-angle glaucoma, angle recession glaucoma, exfoliation syndrome glaucoma, pigmentary glaucoma and chronic angle closure glaucoma) in whom a pressure-lowering intervention was conducted

Exclusion Criteria:

  • Inability to obtain reliable field or optical coherence tomography pre-intervention
  • Visual acuity less than 20/40,
  • Age <18 or >90 years,
  • Other cause for visual field loss not glaucoma, that is, visual field loss due to cataract optic neuropathies, retinal disease
  • Spherical equivalent refractive error > +5.00 Diopters and > 3.00 Diopters cylinder
  • Concomitant cataract and glaucoma surgery

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

  • Observational Models: Cohort
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
IOP between 22-32 mmHg
Forty four (44) patients with intraocular pressure between 22 and 32 millimeters (mmHg) of mercury will undergo Optical Coherence Tomography (OCT); Visual Evoked Potential (VEP); and Humphrey Visual Field (HVF).
Diagnostic test: Optical Coherence Tomography (OCT)
Optical Coherence Tomography (OCT) is a machine that scans eyes and has the capability of measuring thickness of various layers of the retina and nerve fiber layer (NFL).
Other Names:
  • OCT
Diagnostic test: Visual evoked potential (VEP)
Visual Evoked Potential (VEP) is an imaging system that measures electrical activity from the eye to the brain by using electrodes placed on forehead and back of the head similar to electroencephalogram (EEG).
Other Names:
  • VEP
Diagnostic test: Humphrey Visual Field (HVF)
Humphrey Visual Field (HVF) is a test done to evaluate how much peripheral (side) vision has been lost due to glaucoma.
Other Names:
  • VF
IOP greater than 32 mmHg
Six (6) patients with intraocular pressure greater than 32 millimeters of mercury (mmHg) will undergo Optical Coherence Tomography (OCT); Visual Evoked Potential (VEP); and Humphrey Visual Field (HVF).
Diagnostic test: Optical Coherence Tomography (OCT)
Optical Coherence Tomography (OCT) is a machine that scans eyes and has the capability of measuring thickness of various layers of the retina and nerve fiber layer (NFL).
Other Names:
  • OCT
Diagnostic test: Visual evoked potential (VEP)
Visual Evoked Potential (VEP) is an imaging system that measures electrical activity from the eye to the brain by using electrodes placed on forehead and back of the head similar to electroencephalogram (EEG).
Other Names:
  • VEP
Diagnostic test: Humphrey Visual Field (HVF)
Humphrey Visual Field (HVF) is a test done to evaluate how much peripheral (side) vision has been lost due to glaucoma.
Other Names:
  • VF
IOP less than 22 mmHg
Eleven (11) patients with stable intraocular pressure (less than 22 millimeters of mercury (mmHg)) on ophthalmic solutions (eye drops) will undergo Optical Coherence Tomography (OCT); Visual Evoked Potential (VEP); and Humphrey Visual Field (HVF).
Diagnostic test: Optical Coherence Tomography (OCT)
Optical Coherence Tomography (OCT) is a machine that scans eyes and has the capability of measuring thickness of various layers of the retina and nerve fiber layer (NFL).
Other Names:
  • OCT
Diagnostic test: Visual evoked potential (VEP)
Visual Evoked Potential (VEP) is an imaging system that measures electrical activity from the eye to the brain by using electrodes placed on forehead and back of the head similar to electroencephalogram (EEG).
Other Names:
  • VEP
Diagnostic test: Humphrey Visual Field (HVF)
Humphrey Visual Field (HVF) is a test done to evaluate how much peripheral (side) vision has been lost due to glaucoma.
Other Names:
  • VF

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Visual Field Mean Deviation
Time Frame: 12 months
Visual field mean deviation as measured in decibels (dB) is the amount of visual field loss compared to age matched controls (people with no eye diseases or visual field loss). Brightness of the flashes of light used to test peripheral vision during a visual field test is measured in decibels. Brighter light has lower number in decibels. The dimmer the light, the higher the number in decibels with a range of 0 to 40 dB.
12 months
Retinal Nerve Fiber Layer (RNFL) Thickness Measurement
Time Frame: 12 months
Retinal nerve fiber layer (RNFL) thickness in different quadrants of optic nerve and macula are measured pre and postoperatively to evaluate structural changes.
12 months
Average Cup to Disc Ratio
Time Frame: 12 months
Cup to disc ratio is used to evaluate structural changes comparing the size of the cup to the size of the disc during dilated ophthalmic examination. High eye pressure can cause the cup to enlarge, closer to the size of the disc. This measurement is used to follow progression in glaucoma. A normal range for cup to disc ratio would be 0.0 to 0.4. Advanced glaucoma would be 0.8 to 0.9 cup to disc ratio.
12 months
Visual Evoked Potential Amplitudes
Time Frame: 12 months
VEP amplitudes at high contrast as measured in microvolts (μV). Electroencephalogram (EEG) measures electrical activity in the brain. VEP measures electrical activity in areas of the brain responsible for vision by using EEG electrodes. The amplitude measurement is the peak of the energy generated (strongest strength of the signal) from the eye's response to the visual stimulus during the VEP.
12 months
Visual Evoked Potential Latency
Time Frame: 12 months
VEP latency at high contrast as measured in milliseconds (ms). Electroencephalogram (EEG) measures electrical activity in the brain. VEP measures electrical activity in areas of the brain responsible for vision by using EEG electrodes. VEP latencies measure the duration in time of the energy generated (duration of the signal) from the eye's response to a visual stimulus during the VEP.
12 months
Visual Field
Time Frame: 12 months
Visual field pattern standard deviation in decibels (dB). Visual field results compare visual field loss to age matched controls (people with no eye diseases or visual field loss). Brightness of the flashes of light used to test peripheral vision during a visual field test is measured in decibels. With a localized defect in the visual field, pattern standard deviation (PSD) quantifies amount of loss and progression of glaucoma when in the beginning stages of the disease.
12 months

Collaborators and Investigators

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

Sponsor

Wills Eye

Investigators

  • Principal Investigator: George Spaeth, MD, Wills Eye

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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

October 1, 2011

Primary Completion (Actual)

January 1, 2013

Study Completion (Actual)

January 1, 2013

Study Registration Dates

First Submitted

August 10, 2015

First Submitted That Met QC Criteria

November 5, 2015

First Posted (Estimate)

November 9, 2015

Study Record Updates

Last Update Posted (Actual)

March 19, 2018

Last Update Submitted That Met QC Criteria

March 13, 2018

Last Verified

March 1, 2018

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 11-058

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

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.

Clinical Trials on Glaucoma

Clinical Trials on Optical Coherence Tomography (OCT)

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Australia

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe