Determination of true optic disc area using a fundus camera technique: correlation with HRT measurements

Abstract

Abstract: : Purpose: To compare disc areas as measured with Heidelberg Retinal Tomography (HRT) to those obtained with a fundus camera technique. Methods: Forty six subjects ( 88 eyes) who were participating in a glaucoma screening program were enrolled in the study. Disc areas from fundus photographs taken with a Nidek non–mydriatic camera were measured in pixels (Adobe photoshop 7.0). A magnification factor was determined using a previously described technique which uses the position of the focusing knob on the camera to account for the refractive error (Arch Ophthalmol. 2003;121:707–709). The resulting calculated disc areas were then compared with HRT measurements of the same discs. Results: A regression analysis revealed a strong correlation ( r=0.83) between disc areas as measured with HRT and those calculated using the fundus camera technique referred to above. Conclusions: Disc areas can be accurately determined using this simple fundus photographic technique. This may have significant implications for population–based mass glaucoma screening programs.

Keywords: imaging/image analysis: clinical • optic disc