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Xinxing Guo, Zhuoting Zhu, Ou Xiao, Ian George Morgan, Mingguang He; Biometric Progression in Highly Myopic Eyes: The ZOC-BHVI Guangzhou High Myopia Cohort Study. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5483. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Highly myopic eyes pose significantly higher risks of ocular deformation and complications than less myopic eyes. The biometric components and their longitudinal changes of high myopia have largely remained uninvestigated. In this cohort study, we intend to document the biometric progression in high myopia and its determinants.
In this clinic-based cohort study, participants with high myopia (defined as at least -6.00D of spherical power) in both eyes were followed. Biometric measurements including axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and central corneal thickness (CCT) were obtained from optical low-coherence reflectometry (Lenstar LS900, Haag-Streit AG, Koeniz, Switzerland) before cycloplegia at both baseline and at the follow up. Cycloplegic refraction (three drops of 1% cyclopentolate) was measured using an auto-refractor (KR8800, Topcon Corp. Japan) and spherical equivalent refraction (SER) was calculated. Biometric progression was defined as the rate of change for the biometric components. Multiple regression analysis was performed to explore the associations between biometric components and baseline refraction.
A total of 568 highly myopic participants (mean baseline age: 21.4±12.3 years) were followed for a medium of 2.04 years (range: 1.00~3.97 years). Mean measurements at baseline were 27.28±1.40mm for AL, 3.16±0.28mm for ACD, 3.60±0.35mm for LT, and for 545.07±31.49μm for CCT. At the follow-up, ACD and CCT remained stable, while mean progression rate in the right eyes was 0.15±0.02 mm/year for AL, and 0.04±0.03mm/year for LT. In multiple regression analysis, greater AL progression was associated with younger age (β=-0.378, P<0.001) and more myopic baseline SER (β=-0.105, P=0.01); while no associations were observed between LT progression and age, sex, or baseline SER.
Unlike mild to moderate myopia, highly myopic eyes continue to elongate when reaching adulthood. Younger age and more myopic refraction contribute to the greater progression rate, which may also serve as risk factors for disease progression.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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