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Abstract #47870 Published in IGR 13-4
Influence of optic disc size on the diagnostic performance of macular ganglion cell complex and peripapillary retinal nerve fiber layer analyses in glaucoma
Cordeiro DV; Lima VC; Castro DP; Castro LC; Pacheco MA; Lee JM; Dimantas MI; Prata TSClinical Ophthalmology 2011; 5: 1333-1337
Aim: To evaluate the influence of optic disc size on the diagnostic accuracy of macular ganglion cell complex (GCC) and conventional peripapillary retinal nerve fiber layer (pRNFL) analyses provided by spectral domain optical coherence tomography (SD-OCT) in glaucoma. Methods: Eighty-two glaucoma patients and 30 healthy subjects were included. All patients underwent GCC (7 null 7 mm macular grid, consisting of RNFL, ganglion cell and inner plexiform layers) and pRNFL thickness measurement (3.45 mm circular scan) by SD-OCT. One eye was randomly selected for analysis. Initially, receiver operating characteristic (ROC) curves were generated for different GCC and pRNFL parameters. The effect of disc area on the diagnostic accuracy of these parameters was evaluated using a logistic ROC regression model. Subsequently, 1.5, 2.0, and 2.5 mm(2) disc sizes were arbitrarily chosen (based on data distribution) and the predicted areas under the ROC curves (AUCs) and sensitivities were compared at fixed specificities for each. Results: Average mean deviation index for glaucomatous eyes was -5.3 (plus or minus) 5.2 dB. Similar AUCs were found for the best pRNFL (average thickness = 0.872) and GCC parameters (average thickness = 0.824; P = 0.19).The coefficient representing disc area in the ROC regression model was not statistically significant for average pRNFL thickness (-0.176) or average GCC thickness (0.088; P (greater-than or equal to) 0.56). AUCs for fixed disc areas (1.5, 2.0, and 2.5 mm(2)) were 0.904, 0.891, and 0.875 for average pRNFL thickness and 0.834, 0.842, and 0.851 for average GCC thickness, respectively. The highest sensitivities - at 80% specificity for average pRNFL (84.5%) and GCC thicknesses (74.5%) - were found with disc sizes fixed at 1.5 mm(2) and 2.5 mm(2). Conclusion: Diagnostic accuracy was similar between pRNFL and GCC thickness parameters. Although not statistically significant, there was a trend for a better diagnostic accuracy of pRNFL thickness measurement in cases of smaller discs. For GCC analysis, an inverse effect was observed. (copyright) 2011 Cordeiro et al, publisher and licensee Dove Medical Press Ltd.
T. S. Prata. Glaucoma Service, Department of Ophthalmology, Federal University of Sao Paulo, Rua Botucatu, 820, Vila Clementino, Sao Paulo CEP: 04024-002, Brazil. Email: tiagoprata@ig.com.br
Classification:
6.9.2.2 Posterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)
2.13 Retina and retinal nerve fibre layer (Part of: 2 Anatomical structures in glaucoma)
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
