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Jos J Rozema; Changes in correlation between ocular biometry parameters as a function of age and environment. Invest. Ophthalmol. Vis. Sci. 2018;59(9):4752. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
During emmetropization the ocular dimensions of young children gradually adjust themselves to each other so that the global refraction eventually approximates emmetropia. As this process would likely affect the correlations between the biometric parameters, this work assesses how these correlations change with age and area of residence.
Data were collected from 26 reports in the literature for which either the original data (10) or the correlation values (9) were made available to the author, or for which the data could be reconstructed based on the available tables and graphs (7). This led to correlation values between spherical equivalent refraction SE, mean keratometry K, axial length L, lens power PL (calculated with either the Bennett, Bennett-Rabbetts, or SRK/T formula), anterior chamber depth ACD, lens thickness T, and the proportion of axial length and anterior corneal radius of curvature (AL/CR). Correlation values were organised according to the age and living environment (urban or rural) of the subjects involved as mentioned in the original reports. The data spanned an age range between 0 – 75 years; no distinction was made by gender. Note that caution is warranted when comparing correlation values as they may be influenced by e.g. outliers.
For urban subjects the Pearson correlation coefficient r for SE and AL/CR is about –0.25 at birth, which increases to about –0.60 at age 7 and about –0.80 at age 10 and older. In rural subjects, on the other hand, the correlation values remain at about –0.40 at age 10 and older. A similar trend is seen for the correlation between SE and L, suggesting axial length is the main influencing factor for this difference between urban and rural subjects. This is also confirmed by the correlation between K and L, where for the urban subjects the coefficient decreases from about –0.70 at age 8 to about –0.5 in adults, while in rural subjects it remains about the same at –0.72 for the same age range. No major changes with age were seen in the correlations between SE and K, nor for SE and PL for either group.
The influence of axial length on SE refraction increase considerably during the first 10 years of life in city dwellers. Meanwhile for people living in the countryside this influence seems to remain constant with age.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
Changes of the correlation between SE and AL/CR with age for urban (grey) and rural subjects (green).
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