April 2014
Volume 55, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2014
Longitudinal changes in corneal power and axial length in the Correction of Myopia Evaluation Trial (COMET) Cohort
Author Affiliations & Notes
  • Mitchell Scheiman
    Coll of Optometry, Salus University, Elkins Park, PA
  • Li Deng
    31 New England College of Optometry, Boston, MA
  • Jane E Gwiazda
    31 New England College of Optometry, Boston, MA
  • Qinghua Zhang
    Department of Preventive Medicine, Stony Brook University Medical Center, Stony Brook, NY
  • Ruth E Manny
    College of Optometry, University of Houston, Houston, TX
  • Karen D Fern
    College of Optometry, University of Houston, Houston, TX
  • Eric Weissberg
    31 New England College of Optometry, Boston, MA
  • Footnotes
    Commercial Relationships Mitchell Scheiman, None; Li Deng, None; Jane Gwiazda, None; Qinghua Zhang, None; Ruth Manny, None; Karen Fern, None; Eric Weissberg, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science April 2014, Vol.55, 3602. doi:
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      Mitchell Scheiman, Li Deng, Jane E Gwiazda, Qinghua Zhang, Ruth E Manny, Karen D Fern, Eric Weissberg, COMET Study Group; Longitudinal changes in corneal power and axial length in the Correction of Myopia Evaluation Trial (COMET) Cohort. Invest. Ophthalmol. Vis. Sci. 2014;55(13):3602.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: To describe changes in corneal power and axial length (AL) in the COMET cohort followed for 14 years, and explore the relationship between AL and corneal radius (CR) over this time period.

Methods: 469 ethnically diverse, 6-11 year old children with -1.25 to -4.50 D of myopia were enrolled in COMET. Children wore either single vision (SVLs) or progressive addition lenses (PALs) for 5 years and were followed for an additional 9 years wearing PALs, SVLs, or contact lenses. Additionally, 206 non-myopic young adults matched by gender, ethnicity, and age with COMET myopes were recruited at the 12-year visit. Refractive error (cycloplegic autorefraction), corneal curvature (CC, auto-keratometry), and ocular component dimensions (A-scan ultrasound) were measured annually for COMET children, and once for the non-myopic, matched young-adult subjects. Linear mixed model was used to evaluate longitudinal changes based on all available records adjusting for covariates (gender, ethnicity, lens type, baseline age and baseline refraction). Unpaired t-test was used to compare myopes and non-myopes at the 12-year visit. The Pearson correlation coefficient (PCC) between AL and CC was computed at each visit. The comparison of PCCs between myopes and non-myopes at the 12-year visit was conducted using Fisher’s transformation.

Results: Longitudinally, COMET girls had significantly steeper CC than boys (p<0.0001). Caucasians had the steepest CC, and Hispanics the flattest (p=0.001). The correlation between AL and CC was -0.70 (p<0.0001) at baseline and decreased to -0.53 (p<0.0001) at the 14-year visit. The average AL to CR ratio (AL/CR) was 3.15 at baseline and increased to 3.31 at the 14-year visit. In the cross-sectional analysis, the correlation between AL and CC for the COMET myopes at the 12-year visit was lower than for the matched non-myopes (r =-0.57 vs.-0.76; p<0.0001). In addition, the AL/CR in myopes was significantly higher than in non-myopes (3.30 vs. 3.00; p<0.0001).

Conclusions: These data demonstrate significant gender and ethnicity differences in average corneal curvature as myopia progresses. In addition, our findings suggest that as axial length continues to increase in myopic children the cornea may be incapable of further flattening, contributing to myopia progression.

Keywords: 605 myopia  
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