Abstract
Purpose: :
Old world monkeys have been used extensively to study the normal development of the eye and visual system. Although cross sectional histological studies have demonstrated foveal maturation after birth, longitudinal data are not available. The purpose of this study is to assess the maturational time course of the foveal region in infant Macaca mulatta using spectral domain optical coherence tomography (SD-OCT).
Methods: :
The left eyes of sixteen M. mulatta infants were examined with SD-OCT with eye tracking technology (Spectralis HRA-OCT, Heidelberg Engineering, Heidelberg, Germany), starting at around thirty days of age and approximately every thirty days thereafter. Raster scans through the foveal region were analyzed by custom Matlab (2007a, The Mathworks, Natick, Massachusetts) programs to determine outer segment length, overall retinal thickness and foveal pit volume.
Results: :
The preliminary data demonstrate up to 15% increase in mean retinal thickness within the fovea centralis from one to five months of age. Within the same time period a 4% lengthening of the outer segments is observed in this region. Outside the area centralis, the change in average retinal thickness was only 4.7% with a 1% increase in average outer segment height. Although the overall shape of the foveal pit remained the same, the best fit radius of the start of the pit slope and pit circumference at half height decreased by 6.6 and 8.1% respectively.
Conclusions: :
Using SD-OCT, changes in both outer segment length and overall retinal thickness are observed within the foveal region of non-human primate infants. These data suggest that the fovea centralis in M. mulatta continues to mature for at least the first five months of life. Development of this region will be monitored until retinal features are adult-like.
Keywords: retinal development • macula/fovea