Nerve fibre layer measurement of the Hong Kong Chinese population by scanning laser polarimetry

Purpose To obtain normal retinal nerve fibre layer (RNFL) measurements by s canning laser polarimetry in a local Hong Kong Chinese population and to id entify the correlation of the measurements with age. Methods One hundred and fifty-nine normal Hong Kong Chinese volunteers of d ifferent ages were recruited for this study. RNFL values were measured usin g a Nerve Fibre Analyzer GDx (Laser Diagnostic Technologies, CA). Results Mean peripapillary RNFL measurements at the superior, inferior, tem poral and nasal regions were 95.0 +/- 15.6, 97.0 +/- 16.3, 47.0 +/- 9.0 and 43.9 +/- 15.1 mu m respectively (mean +/- SD). There was a highly signific ant negative correlation in average RNFL values with increasing age (-1.9 m u m per decade, p = 0.001). A significant negative correlation with increas ing age was also identified in the RNFL values in all four regions and they decreased by similar amounts (p < 0.05). No correlation with age was obser ved for relative ratio parameters such as superior/nasal ratio, inferior/na sal ratio and max, modulation (p > 0.05). Conclusion RNFL values of the Hong Kong Chinese population appeared to decr ease over time cross-sectionally. Since they decreased by similar amounts a t four regions, use of relative ratio parameters for analysis has an advant age over absolute values, as they were not affected by age.