Abstract
Purpose::
to determine the normative range for peripapillary retinal nerve fiber layer (RNFL) thickness measured with scanning laser polarimetry with a variable corneal compensator (GDxVCC) in a group of children compared to adults.
Methods::
Sixty normal children (mean age 7.9±2.1 years; range 4-12 years) and 60 normal adults (mean age 51.2±10.5 years; range 28-72 years) were included. All subjects underwent a complete ophthalmologic examination and imaging with GDxVCC. The 15 parameters listed on the Extended Parameter Table printout were considered in the analysis. Differences between groups were compared using the Mann-Whitney test. Variations in GDxVCC parameters in relation to age were studied with linear regression analysis.
Results::
The mean RNFL thickness in the children was slightly greater than the adults (58.3±5.4 µm vs.56.3±5.5 µm; P=0.048). The mean RNFL thickness in the inferior sector (inferior average) was significantly greater in the children than in the adults (67.7±7.9 µm vs.62.7±6.7 µm; P=0.001). The parameters: inferior maximum, TSNIT SD, normalized superior area and normalized inferior were also significantly higher in the children (P<0.05). Linear regression analysis for the various GDxVCC parameters in relation to age showed that the inferior average was the only dependant variable that significantly decreased with age.
Conclusions::
The mean thickness and mean inferior thickness of the peripapillary RNFL measured with GDxVCC were significantly greater in the group of children than in the group of adults. This implies that the GDxVCC built-in normative database cannot be applied to results obtained in children. Our normative data ranges in normal pediatric patients can be beneficial in using and interpreting GDxVCC results in cases of optic neuropathies, like glaucoma, optic nerve atrophy, and pathologies causing optic disc cupping and RNFL thinning (as shown in the examples).
Keywords: optic disc • imaging/image analysis: clinical • nerve fiber layer