Automated diagnosis of glaucoma disease has been studied for years. A great amount of research work in this field has been focused on the analysis of retinal fundus images to localize, detect and evaluate the optic disc. An open fundus image database with accurate gold standards of the optic nerve head has been implemented. A variability measurement by zones of the optic disc is also proposed. The relevance of this work is to provide accurate ONH segmentations and a segmentation assessment procedure to allow the design of computerized methods for glaucoma detection.

Purpose. We evaluated and compared the ability of a new method for measuring hemoglobin (Hb) levels at the optic nerve head (ONH) to that of visual field evaluation, scanning laser ophthalmoscopy (HRT), scanning laser polarimetry (GDx), and optical coherence tomography (OCT) for diagnosing glaucoma. Methods. Healthy eyes (n = 102) and glaucomatous eyes (n = 101) underwent reliable Oculus Spark perimetry, and imaging with the HRT, GDx, and Cirrus OCT. In addition, ONH color images were acquired with a non-mydriatic fundus camera. The Laguna ON_hE program then was used to calculate the Hb amount in each of 24 sectors of the ONH. Sensitivities at 95% fixed specificity, diagnostic agreement, and linear correlations between parameters with the best diagnostic ability were calculated. Results. The glaucoma discriminant function (GDF) of the Laguna program, evaluating Hb in the vertical intermediate sectors and center/periphery Hb amount slope, yielded an 89.1% sensitivity and 95.1% specificity, which was superior or similar to the other tests. The best GDF diagnostic agreement was for the OCT-vertical cup-to-disc (C/D) ratio (kappa = 0.772) and the final phase Spark pattern SD (kappa = 0.672). Hb levels correlated strongly with the Spark mean sensitivity (first phase 0.70, final phase 0.71). Hb also correlated well with the Reinhard OW Burk discriminant function of the HRT (0.56), nerve fiber indicator of GDx (−0.64), and vertical C/D ratio of OCT (0.71). Conclusions. Hb levels evaluated by color analysis of ONH photographs had high reproducibility, a high sensitivity–specificity balance, and moderate to strong agreement with other structural and functional tests.

Purpose:To calculate the amount of hemoglobin (Hb) in sectors of the optic nerve head (ONH) from stereoscopic color fundus images using the Laguna ONhE method and compare the results to the visual field evaluation and optical coherence tomography (OCT). Methods:Healthy eyes (n=87) and glaucoma eyes (n=71) underwent reliable Oculus Spark perimetry and Cirrus OCT. ONH color images were acquired with a non-mydriatic stereoscopic Wx Kowa fundus camera. Laguna ONhE program was applied to these images to calculate the Hb amount in the cup and 6 sectors of the rim. Receiver operating characteristic (ROC) analysis and correlations between parameters were calculated. Results:We did not observe any variations in the amount of hemoglobin in relation to age in normal subjects (R2=0.033, P>0.05). Maximum ROC area confidence intervals were observed for a combination between perimetric indices and the Laguna ONhE Glaucoma Discriminant Function (0.970-0.899) followed by rim area (0.960-0.883) and mean deviation (MD) (0.944-0.857). In glaucoma cases, Hb amount presented significant reduction in all rim sectors, especially 231-270º and 81-120º (P<0.001), except in the temporal 311-40º (P=0.11). Perimetry mean sensitivity by sectors was better correlated with respective hemoglobin levels than with rim areas or the corresponding nerve fiber thickness, especially the superior and inferior sectors (p<0.05). Conclusions:Visual field sensitivity was better correlated with hemoglobin levels than with rim sector areas or the corresponding nerve fiber thickness. In many cases the remaining rim showed insufficient perfusion, especially in the superior and inferior sectors.

Purpose: To evaluate the diagnostic ability of a new perimetric procedure in glaucoma. Methods: Pulsar perimeter shows white circular sinusoidal grating patterns with decreasing amplitude, 5° in diameter, 500 msec in duration in 66 locations. The stimuli scale combines spatial resolution and contrast. The stimuli were shown with centrifugal wave motion at 8 cyl/deg (K6W) or pulse at 30 Hz (T30W). Fifty-six normal eyes and 82 eyes with ocular hypertension and mild glaucoma were included. These 82 cases were classified into four levels of diagnostic certainty, from 0 (ocular hypertension) to 3 (mild glaucoma). Results: Mean examination time was 3:49 min. Specificity was 96.4% (T30W) and 94.6% (K6W). Sensitivities for levels 0 and 3 were 34.5% to 100% (T30W) and 24.1% to 75% (K6W). The receiver operating characteristic (ROC) curve areas for T30W at levels 1, 2, and 3 were 0.88, 0.94, and 0.99. The ROC areas for K6W were 0.83, 0.91, and 0.97. There was good correlation between both Pulsar perimetries (r=0.88), but it was lower with conventional perimetry (r=0.58 for T30W and r=0.59 for K6W). Conclusions: The novel Pulsar T30W perimetry may be helpful for the study of mild glaucoma and ocular hypertension.

Background/aims: To determine the structure–function relationship throughout the different stages of glaucoma. Methods: Subjects: 228 controls and 1007 suspected, early, moderate, or advanced glaucomas. In controls, Pearson coefficient of variation (PCV) of standard automated perimetry mean sensitivity (SAP-MS) and global mean retinal nerve fibre layer thickness (RNFL, Heidelberg Retina Tomograph) were calculated. Piecewise linear regression was used to evaluate if the data were related better to two separate regression lines in all population. Results: PCV for SAP-MS and RNFL was 6.19% and 29.27%, respectively. For SAP-MS >22.42 dB (piecewise linear regression-obtained breakpoint, p<0.05), the logarithmic and linear relationships between SAP-MS and mean RNFL thickness were not different (r = 0.182, r = 0.185 respectively; p = 0.950). For SAP-MS <22.42 dB, the logarithmic and linear relationships between SAP-MS and mean RNFL thickness were not different (r = 0.353, r = 0.344 respectively; p = 0.884). Conclusion: The logarithmic and linear relationships between SAP-MS and mean RNFL thickness did not differ when individuals were stratified using the piecewise linear regression-obtained cut-off point. The curvilinear relationship between the morphological and perimetric results may be due to the wide variability in normal morphology and limitations in the dynamic range of the morphological tests in cases with moderate and severe defects.

A new method for automatic optic disc localization and segmentation is presented. The localization procedure combines vascular and brightness information to provide the best estimate of the optic disc center which is the starting point for the segmentation algorithm. A detection rate of 99.58% and 100% was achieved for the Messidor and ONHSD databases, respectively. A simple circular approximation to the optic disc boundary is proposed based on the maximum average contrast between the inner and outer ring of a circle centered on the estimated location. An average overlap coefficient of 0.890 and 0.865 was achieved for the same datasets, outperforming other state of the art methods. The results obtained confirm the advantages of using a simple circular model under non-ideal conditions as opposed to more complex deformable models.