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Variability in Perimetry Study (VIPII)

This study has been completed.
Information provided by (Responsible Party):
VA Office of Research and Development Identifier:
First received: January 15, 2010
Last updated: February 13, 2017
Last verified: February 2017

January 15, 2010
February 13, 2017
July 2010
September 2015   (Final data collection date for primary outcome measure)
Number of Subjects Progressing in Each Group Using Pointwise Linear Regression [ Time Frame: 4 years ]
Perimetric method that most efficiently detects visual field change. secondary outcome: number of subjects progressing in each group using pointwise linear regression Linear regression was used to determine visual field worsening (progression) at each of 52 test locations. We required 3 or more worsening test locations at a p = 0.05 significance level for their to be significant progression.
time to significant visual field change [ Time Frame: 4 years ]
Complete list of historical versions of study NCT01051739 on Archive Site
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Variability in Perimetry Study
Improved Assessment of Visual Field Change
Improved Assessment of Visual Field Change is a trial aimed at investigating mechanisms of visual field testing variability. The investigators have found using larger stimulus size substantially lowers short-term variability. In this study, the investigators will determine if larger stimuli detect visual field change at an earlier time. The investigators are also developing a statistical model that accounts for correlations of neighboring test locations.

Disease of the optic nerve, including glaucoma, is the leading cause of blindness in the United States. Treatment decisions for optic nerve diseases are based largely on the changes in visual function that occur mostly as a consequence of disease progression. Unfortunately, the decision as to whether change of visual function has occurred is often difficult because of the high retest variability of conventional visual field testing (perimetry). This variability is so high that with moderate visual loss, a minimum of six tests are often needed in patients with optic nerve damage to reliably distinguish visual field deterioration from random variation. The preliminary data show that a substantial portion of the variability of perimetry lies in the type of stimulus used and the testing strategy applied.

OBJECTIVES: The investigators propose to test the hypothesis that a large portion of total perimetric variability in patients with visual loss is due to a poor signal-to-noise ratio associated with using a small fixed-size stimulus.

RESEARCH PLAN AND METHODS: To test this hypothesis, the investigators are examining patients with optic nerve diseases with conventional automated perimetry (size III) and tests having large-sized and scaled stimuli (size V, size VI (custom perimeter) and luminance size threshold perimetry - a test where threshold is found by changing stimulus size rather than stimulus intensity). Over four years the investigators will test 100 patients with and glaucoma and 60 normals each eight times. In addition, the investigators are retesting 50 subjects once a week for 5 weeks. The investigators are also studying the associated structural-functional correlations using OCT and developing a statistical model that accounts for correlations of neighboring test locations.

Perimetric variability and the reliable identification of visual field change is the single most difficult problem in visual testing today. The investigators anticipate identifying a method that allows efficient and accurate determination of visual field change. Identification of a superior method would (1) reduce the number of examinations needed, thereby reducing the costs of medical care; (2) minimize misdiagnosis, unnecessary testing and even unnecessary surgery that results from mistakenly interpreting fluctuation of the visual field as progression or improvement; (3) allow earlier disease intervention and (4) reduce the costs of clinical trials.

Observational Model: Case-Control
Time Perspective: Prospective
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Probability Sample
glaucoma patient with 0 to -25 dB mean deviation and normal subjects
Procedure: Comparison of four visual field testing strategies
We compared the ability of four perimetric strategies to detect visual field change in the glaucoma arm.
  • Group 1
    Intervention: Procedure: Comparison of four visual field testing strategies
  • Group 2
    Intervention: Procedure: Comparison of four visual field testing strategies

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
September 2015
September 2015   (Final data collection date for primary outcome measure)

Inclusion Criteria:

  • Mean deviation of -20 or better with 5-8 points (optimally 10 points) with a value of p= 0.05 or better on the total deviation plot
  • Mild cataract with VA of 20/30 or better pinholed
  • Refractive error of = to or less than 6 diopters with = or less than 3.50 diopters of cylinder
  • Pupil diameter of 3 mm minimum
  • Controlled hypertension, diabetes, migraine
  • Pseudophakic/refractive surgery if no vision problems
  • Trabeculectomy okay

Exclusion Criteria:

  • History of other ocular or neurologic disease or surgery
  • History of stroke
  • Systemic disease [lupus, graves, cancer (within the last 5 yrs), AIDS, other]
  • History of amblyopia
  • Unreliable patient
  • Frequently misses appointments
  • Tests poorly
  • Ocular hypertension
  • Retinal problems
  • Diabetic retinopathy
  • Neurological disease (IIH, ON, AION)
  • Cancer not in remission for the last 5 years
  • Vein or artery occlusions
  • Macular degeneration
  • Trauma with vision loss
  • Ocular inflammation (pars planitis, iritis, temporal aeuritis)
Sexes Eligible for Study: All
18 Years to 99 Years   (Adult, Senior)
Contact information is only displayed when the study is recruiting subjects
United States
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VA Office of Research and Development
VA Office of Research and Development
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Principal Investigator: Michael Wall, MD Iowa City VA Health Care System, Iowa City, IA
VA Office of Research and Development
February 2017

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP