Asymmetry of Retinal Nerve Fiber Layer and Posterior Pole Asymmetry Analysis Parameters of Spectral Domain Optical Coherence Tomography in Children.

PURPOSE

To determine inter- and intraocular differences in the retinal nerve fiber (RNFL) and posterior pole asymmetry analysis (PPAA) macular thickness parameters in children using spectral domain optical coherence tomography.

METHOD

A prospective, cross-sectional study involving 126 subjects between the age group of 5-15 years received a standardized eye examination including spectral domain optical coherence tomography for retinal nerve fiber layer and macular thickness measurements. Asymmetry was calculated as the difference between the right and left eyes as well as the superior and inferior area of one randomly selected eye for each subject. Normal ranges were established as the 2.5 and the 97.5 percentiles. Correlation between the right and left eyes were assessed by intraclass correlation coefficients.

RESULTS

The difference in the average and superior RNFL between the right and the left eye was not statistically significant. The interocular 2.5 and 97.5 percentile limits for RNFL thickness and total PPAA macular thickness were -7.75 to 12.5 microns and -9 to 21 microns, respectively. The 2.5 and 97.5 percentile limits of the intraocular superior-inferior area difference for the RNFL thickness and PPAA macular thickness were -40 to 37 microns and -32 to 38 microns, respectively. A strong correlation for all parameters between the right and the left eye was seen.

CONCLUSION

The normal interocular RNFL and PPAA macular thickness asymmetry should not exceed 12.5 microns and 21 microns, respectively. Similar intraocular limits for superior-inferior asymmetry should not exceed 40 and 38 microns, respectively.