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Study of Theories About Myopia Progression (STAMP)

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ClinicalTrials.gov Identifier: NCT00335049
Recruitment Status : Completed
First Posted : June 8, 2006
Last Update Posted : October 8, 2010
Sponsor:
Collaborator:
National Eye Institute (NEI)
Information provided by:
Ohio State University

Brief Summary:
At this time, we do not know what causes a child to become more nearsighted (myopic). STAMP will help us better understand nearsightedness in children. Children will be randomly chosen to wear regular glasses (single vision lenses) or no-line bifocal glasses (progressive addition lenses) for the first year of the study. All children will wear regular glasses for the second year of the study. STAMP will compare how the eye changes shape in the two groups to help us understand why children become nearsighted. The two theories of myopia progression that are being evaluated are based on different factors. One theory is based on environmental factors such as extended near work while the other theory is based on genetically coded factors.

Condition or disease Intervention/treatment Phase
Myopia Device: progressive addition spectacle lens (bifocal) Device: Single Vision Lenses (SVLs) Not Applicable

Detailed Description:

Eligible children will be enrolled, randomized, and followed at six-month intervals for two years with all children wearing single vision lenses for the second year. At each visit, complete measurements of the components of the eye will be made to explain the mechanism responsible for the Progressive Addition Lens (PAL) treatment effect and why it occurs mainly during the first year of bifocal wear (Gwiazda et al. 2003). While hyperopic retinal blur (blur at the back of the eye) due to accommodative lag (poor focusing when doing close work) has been proposed as a possible mechanism driving myopia progression (Gwiazda et al. 1993), others have shown that accommodative lag accompanies rather than precedes the onset of myopia (Mutti et al., 2006). This suggests that accommodative lag is a result of another possible mechanism resulting in myopia progression such as crystalline lens-induced ciliary-choroidal tension (a model in which the lens in the eye is stretched and is not as good at focusing up close) (Mutti et al., 2000). According to this proposed mechanism, high accommodative lag in myopia results from increased crystalline lens tension that is transmitted through the choroid (an outside layer of the eye). This tension results in restricted equatorial (the vertical dimension of the eye) eye growth with no axial (front to back) restriction to eye growth and yields a prolate ocular shape (an eye that is longer than it is wide) in myopes (Mutti et al., 2000).

Comparisons: Refractive error (glasses prescription), axial length (length of the eye), peripheral eye shape, accommodation (focusing ability), corneal shape (shape of the front of the eye), anterior chamber depth, crystalline lens thickness and curvatures (shape of the lens in the eye), central and peripheral higher-order aberrations (how well light focuses in the eye), and phoria (eye alignment) will be measured at six-month intervals. The primary study outcome is refractive error measured by cycloplegic autorefraction. Comparison of the biometric data collected both during the first year when the PAL intervention is present and during the second year when the PAL intervention is removed will allow us to differentiate between the two theories under consideration. We will also evaluate whether the modest PAL treatment effect that has been reported during the first year of PAL wear is permanent.


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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 85 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Study of Theories About Myopia Progression (STAMP)
Study Start Date : December 2006
Actual Primary Completion Date : July 2010
Actual Study Completion Date : July 2010

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Experimental: PAL
Progressive Addition Spectacle Lenses (PALs) with a +2.00 D add worn for first year off study. Single Vision Lenses worn for second year of study.
Device: progressive addition spectacle lens (bifocal)
Progressive addition lenses (PAL) with a +2.00 D add.
Other Name: PAL

Active Comparator: SVL
Single Vision Lenses (SVLs) worn both years of the study.
Device: Single Vision Lenses (SVLs)
Single vision spectacle lenses.
Other Name: SVL




Primary Outcome Measures :
  1. Cycloplegic autorefraction [ Time Frame: Baseline, 6, 12, 18, and 24 months ]

Secondary Outcome Measures :
  1. Phoria [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
  2. Accommodative lag [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
  3. AC/A ratio [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
  4. Corneal shape and thickness [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
  5. Intraocular pressure [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
  6. Peripheral ocular shape [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
  7. Central and peripheral aberrations [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
  8. Crystalline lens thickness and curvature [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
  9. Anterior chamber depth [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
  10. Axial length [ Time Frame: Baseline, 6, 12, 18, and 24 months ]


Information from the National Library of Medicine

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Ages Eligible for Study:   6 Years to 11 Years   (Child)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • 6 to 11 years of age
  • Best corrected vision of at least 20/30 in each eye
  • Birth weight > 1250g

(The criteria below will be evaluated at a screening visit to find out if the child can participate)

  • Accommodative lag >= 1.30 D (for a 4D stimulus)
  • At least -0.75 D myopia in each meridian measured with cycloplegic autorefraction but not more than -4.50 D in each meridian in each eye
  • Esophoria at near if more than -2.25 D spherical equivalent (high myopia)
  • Astigmatism < 2.00 DC in each eye
  • Anisometropia < 2.00 D

Exclusion Criteria:

  • Strabismus (eye turn)
  • History of contact lens wear
  • History of previous bifocal wear
  • Diabetes mellitus

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00335049


Locations
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United States, Ohio
The Ohio State University College of Optometry
Columbus, Ohio, United States, 43210
Sponsors and Collaborators
Ohio State University
National Eye Institute (NEI)
Investigators
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Principal Investigator: David A Berntsen, OD, PhD University of Houston
Principal Investigator: Karla Zadnik, OD, PhD Ohio State University
Principal Investigator: Donald O Mutti, OD, PhD Ohio State University

Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
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Responsible Party: Karla Zadnik, OD PhD / Principal Investigator, The Ohio State University
ClinicalTrials.gov Identifier: NCT00335049     History of Changes
Other Study ID Numbers: 2005H0157
K12EY015447 ( U.S. NIH Grant/Contract )
First Posted: June 8, 2006    Key Record Dates
Last Update Posted: October 8, 2010
Last Verified: October 2010

Keywords provided by Ohio State University:
myopia progression
bifocal

Additional relevant MeSH terms:
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Myopia
Disease Progression
Disease Attributes
Pathologic Processes
Refractive Errors
Eye Diseases