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Pauline Kang, Lindsay Bloch, Sarah Gosling, Douglas Grimson, Jenna Owen, Ahmed Alharbi, Paul Gifford, Helen A. Swarbrick; Peripheral Refraction And Axial Length At Corresponding Retinal Locations. Invest. Ophthalmol. Vis. Sci. 2011;52(14):2829.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the correlation between refractive error obtained by autorefraction and axial length measured using the IOLMaster at corresponding peripheral retinal locations.
61 young adult subjects (19 to 31 years) were enrolled and categorized into three refractive groups based on central spherical equivalent refractive error: hyperopes (>+0.50DS), emmetropes (-0.49DS to +0.49DS) and myopes (<-0.50DS). Following cycloplegia, autorefraction and axial length measurements were taken at center and 25° in both nasal and temporal visual fields using the Shin-Nippon NVision-K 5001 autorefractor and IOLMaster respectively. Simple schematic eye calculations using central refraction and axial length determined overall eye power. Coupled with relative peripheral refraction data, this allowed calculation of peripheral axial length. Linear regression analysis and Bland-Altman plots were used to compare retinal shape profiles determined by the two methods. A p-value of 0.05 was used to denote statistical significance.
There was a statistically significant correlation between central refraction and axial length (R2=0.359, p<0.001). Greater amounts of central myopia were associated with longer axial lengths. Analysis of all data revealed a statistically significant correlation between axial length measured with the IOLMaster and calculated through peripheral refraction in both the nasal (R2=0.691, p<0.001) and temporal (R2=0.723, p<0.001) visual fields. Relative to IOLMaster measurements, axial length was over-estimated when calculated from peripheral refraction data by +0.48 ± 0.60mm in the nasal retina and +0.62 ± 0.61mm in the temporal retina. Furthermore, significant correlations were still evident when analysis was conducted separately for each refractive group.
There was a strong correlation between axial length determined by the IOLMaster and calculated from peripheral refraction. Assumptions made for the calculation of peripheral axial length should be revisited to refine the relationship between calculated and measured peripheral axial length and to determine if peripheral refraction can accurately describe ocular shape.
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