Aim: To investigate the relationship between optic disc area and axial length in normal eyes of white and black people.
Methods: Consecutive eligible normal subjects were enrolled. Ocular biometry was obtained using A-scan ultrasonography, and reliable images of the optic disc were obtained using a confocal scanning laser ophthalmoscope. The relationship between optic disc area and axial length was assessed using univariate and multivariate models.
Results: 281 eyes of 281 subjects were enrolled. Black subjects (n = 157) had significantly larger discs (mean (SD) disc area, 2.12 (0.5) mm2) than white subjects (n = 124; 1.97 (0.6) mm2; t test, p = 0.02). Optic disc area increased with axial length (Pearson’s correlation coefficient, r = 0.13, p<0.035) for the entire study population. Multivariate regression models including race, disc area and axial length showed that a significant but weak linear relationship exists between axial length and disc area (partial correlation coefficient 0.14; p<0.024), and with race and disc area (partial correlation coefficient 0.19; p<0.017) when adjusted for the effects of other terms in the model.
Conclusion: Increased disc area is associated with longer axial length measurements and African ancestry. This may have implications for pathophysiology and risk assessment of glaucoma.
- HRT II, Heidelberg Retina Tomograph II
- IOP, intraocular pressure
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Funding: This work was supported in part by The Jane Banks Research Fund, The New York Glaucoma Research Institute, New York, NY and grant number K23-EY 13959-01.
Competing interests: None declared.
This work was presented in part at the annual meeting of the Association for Research in Vision and Ophthalmology 2005.
Published Online First 20 September 2006