Abstract
Purpose: :
To investigate the birefringence of the central cornea in children. Corneal birefringence is a well-known confounding factor with all polarization-sensitive technology used for retinal scanning and other intraocular assessment. It has been studied extensively in adults, but little is known regarding age-related differences. Specifically no information is available concerning corneal birefringence in children. For applications that are geared towards children, such as retinal birefringence scanning for strabismus screening purposes, it is important to know the expected range of both corneal retardance and azimuth in pediatric populations.
Methods: :
Corneal birefringence was measured in both eyes of 91 subjects, including 43 children (aged 3 to 17 years) and 48 adults (aged 18 to 70 years), by means of scanning laser polarimetry (GDx-VCCTM, Carl Zeiss Meditec, Inc.). Children’s measures of corneal retardance and azimuth were compared with those obtained in adults.
Results: :
As with previous studies in adults, we found corneal birefringence to vary widely in children, with corneal retardance ranging from 10 nm to 77 nm, and azimuth (slow axis) ranging from -11° to 71° (measured downward from nasally). No significant differences in central corneal birefringence were found between children and adults. Further linear regression analysis did not reveal any significant age-related differences in general.
Conclusions: :
This study, for the first time, investigated the birefringence of the central cornea in children. Our results suggest that there are no significant differences in central corneal birefringence between children and adults, which is in accord with available literature on structural changes of the central cornea with development and aging. Establishing knowledge of the polarization properties of the central cornea in children allows better understanding of, exploitation of, or compensation for, these effects in new polarization-sensitive pediatric applications.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • optical properties • screening for ambylopia and strabismus