Position of retinal blood vessels correlates with retinal nerve fibre layer thickness profiles as measured with GDx VCC and ECC

Aim To evaluate the correlation of the retinal blood vessel position and the retinal nerve fibre layer (RNFL) thickness profile. Methods RNFL thickness of 81 healthy subjects was measured using scanning laser polarimetry (SLP). To quantify the retinal blood vessel position, the angle (superior and inferior) between a horizontal line and a line from the optic disc centre to the intersection of the most temporal major retinal blood vessel and the outer margin of the measurement ellipse was measured on the SLP printout. Results A negative correlation was found between both the superior and inferior angle and the superotemporal and inferotemporal RNFL thickness, and a positive correlation between both angles and the superonasal and inferonasal RFNL thickness. The steepest slope of the regression line was located in the superotemporal and inferotemporal regions (-0.7 to -1.0 mu m/degrees). Using this slope, the difference in RNFL thickness for the interquartile range of the superior angle was 13 mu m. Conclusion RNFL thickness profiles correlate with the location of the main temporal superior and inferior blood vessels. The application of a normative database, taking into account the position of major blood vessels, might improve the diagnostic power of RNFL measurement.