Effect of fundus image devices for early diagnosis of primary open angle glaucoma

Abstract

Evaluation of the optic disc and retinal nerve fiber layer measurements (RNFL) with stereophotography is the current "gold standard" for the diagnosis of early primary open angle glaucoma (POAG), but it is still subjective and is dependent too much upon an experienced observer. Substantial variability exists in the interpretation of optic disc change over time. There are consistent evidences that image analysis devices such as optical coherence tomography (OCT) and Heidelberg retina tomograph (HRT-II) can detect early to moderate glaucoma as well as expert assessment of stereoscopic optic disc and RNFL photographs. Optic disc and RNFL defect can be quantitatively measured by these devices. But the sensitivity and specificity of the measurements obtained with these devices are not good enough for the early diagnosis of POAG at this time due to several reasons, such as individual variety of the structure parameters in normal subjects, lack of powerful normative database, lack of diagnostic parameters which are good enough both in sensitivity and specificity for detecting early glaucoma damage. However, information obtained from these image analysis devices might be helpful in early POAG diagnosis if clinicians can understand the advantages and limitations of these instruments.