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
|Condition or disease||Intervention/treatment||Phase|
|Myopia||Device: progressive addition spectacle lens (bifocal) Device: Single Vision Lenses (SVLs)||Not Applicable|
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.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||85 participants|
|Intervention Model:||Crossover Assignment|
|Masking:||Double (Participant, Outcomes Assessor)|
|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|
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
- Cycloplegic autorefraction [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
- Phoria [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
- Accommodative lag [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
- AC/A ratio [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
- Corneal shape and thickness [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
- Intraocular pressure [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
- Peripheral ocular shape [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
- Central and peripheral aberrations [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
- Crystalline lens thickness and curvature [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
- Anterior chamber depth [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
- Axial length [ Time Frame: Baseline, 6, 12, 18, and 24 months ]
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
|United States, Ohio|
|The Ohio State University College of Optometry|
|Columbus, Ohio, United States, 43210|
|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|