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Donald O. Mutti, Loraine T. Sinnott, G. Lynn Mitchell, Lisa A. Jones-Jordan; Ocular Component Growth Curves in Human Infants and Early Childhood. Invest. Ophthalmol. Vis. Sci. 2012;53(14):140. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To characterize the growth of each major ocular component in human infants and children between 3 months and 7.5 years of age.
A cohort of 297 infants had between 1 and 7 measurement visits at 0.25, 0.75, 1.5, 3.0, 4.5, 6.5, and 7.5 years of age. Ocular components measured included cycloplegic refractive error, A-scan axial dimensions (anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL)), corneal power, and crystalline lens equivalent power and refractive index. Growth curves as a function of age were evaluated in linear, exponential, and a combination of linear and exponential forms. Exponential growth and decay models were also considered. Models were evaluated by visual comparisons to non-parametric models and by assessment of the Akaike Information Criterion value.
Of 13 ocular components evaluated, 12 were best fit using a combination of an early exponential phase followed by a later linear phase. The early exponential phase generally ended by 1-2 years of age. The exponential phase showed increases with age for ACD, VCD, AL, and radius of curvature for each crystalline lens surface, but decreases with age for refractive error, LT, and the power of the crystalline lens and cornea. The linear phase continued to either increase or decrease in the same direction as the early exponential phase with the exception of refractive error and corneal power; these showed little change after about 18 months of age. All 12 components underwent substantial amounts of change with age. VCD and AL increased by about 3.5mm, corneal power decreased by about 1.75D, and crystalline lens equivalent power decreased by 15.0D. Hyperopic refractive error decreased by about 1.0D. Crystalline lens equivalent refractive index required an exponential growth and decay model to adequately capture its early increase from 1.45 at 3 months, an inflection point at about 18 months of age at 1.46, and subsequent decrease back to 1.45 by age 8 years.
The development of the majority of ocular components can be described using an early exponential phase followed by a later linear phase, indicating rapid early change followed by slower, sustained change. These growth curves may assist eyecare providers such as surgeons performing early cataract extraction who need to achieve a future targeted refractive error. The crystalline lens refractive index followed a unique pattern of growth and decay. The source and implications of this exception require further study.
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