Optic disc imaging — the influence of quality on image analysis

Abstract

Aim: To evaluate the influence of image quality on the measurement of optic disc cupping in fundus photographs. Material: Data from 58 patients, aged 30 to 85 years, with suspected or manifest glaucoma were analyzed. Methods: Measures of the optic cup area were performed by a semi-automatic planimetric program, the Retinal Size Tool (RST), on the fundus photographs. The cup size measure was compared with corresponding value in the Heidelberg retina tomograph (HRT), using the Glaucoma Probability Score (GPS) program. The quality of the fundus photographs was graded by an Automated Quality Evaluation program (AQE), and by two independent observers. Results: Sixty-two percent of the fundus photographs were classifed as acceptable or better by the AQE, while the independent observers classified only one image (2%) as not acceptable for visual evaluation of the optic disc. RST cup size measures both from images with acceptable and poor quality showed good correlations with HRT GPS measures. Conclusion: Planimetric measurements of optic disc parameters could be performed also on images with low over-all quality according to automatic analysis of illumination and sharpness.