Abstract
Purpose:
To investigate the effect of axial length on false positive rate of the sectoral peripapillary retinal nerve fiber layer (RNFL) thickness in young Japanese healthy eyes when using the built-in normative database.
Methods:
Prospective observational cross-sectional study comprised 126 right eyes. All participants (mean age 26.0 ± 4.1) underwent comprehensive ophthalmologic examination, including axial length and peripapillary RNFL thickness imaging. Axial length was measured with the AL-2000 ultrasound device (TOMEY, Japan). RNFL thickness was assessed using the TOPCON 3D OCT-1000 MARK II RNFL 3.4 mm circle scan and divided into twelve 30-degrees sectors (clock hours) around the optic disc. The twelve sectorial RNFL thicknesses were evaluated at the 5% probability level for significant disparities in comparison with built in RNFL normative database (false positive sector). The relationship between the number of false positive sector and the axial length was investigated using linear regression analysis.
Results:
The mean axial length was 25.43 ± 1.45 mm. Thirty six eyes (28.6%) had one or more false positive clock-hour sectors. The false positive sector was seen with a high frequency in sector 6 (25.4 %). The axial length of the eyes with false positive sectors (26.50 mm) was significantly longer than that of the eyes without false positive sectors (25.00 mm) (p<0.001). The number of false positive sectors was significantly positively associated with the axial length (r=0.50, p<0.001).
Conclusions:
In clock hour sectoral RNFL thickness, the number of false positive sectors increased as the axial length increased. The relationship should be considered when using the built-in normative database.
Keywords: 550 imaging/image analysis: clinical