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Abstract #6348 Published in IGR 3-2

Detecting early glaucoma by assessment of retinal nerve fiber layer thickness and visual function

Bowd C; Zangwill LM; Berry CC; Blumenthal EZ; Vasile C; Sanchez-Galeana CA; Bosworth CF; Sample PA; Weinreb RN
Investigative Ophthalmology and Visual Science 2001; 42: 1993-2003

PURPOSE: To compare the abilities of scanning laser polarimetry (SLP), optical coherence tomography (OCT), short wavelength automated perimetry (SWAP), and frequency-doubling technology (FDT) perimetry to discriminate between healthy eyes and those with early glaucoma, classified based on standard automated perimetry (SAP) and optic disc appearance. To determine the agreement among instruments for classifying eyes as glaucomatous. METHODS: One eye of each of 94 subjects was included. Healthy eyes (n = 38) had both normal-appearing optic discs and normal SAP results. Glaucoma by SAP (n = 42) required a repeatable abnormal result (glaucoma hemifield test (GHT) or corrected pattern standard deviation (CPSD) outside normal limits). Glaucoma by disc appearance (n = 5) was based on masked stereoscopic photograph evaluation. Receiver operating characteristic (ROC) curve areas, sensitivities, and specificities were calculated for each instrument separately for each diagnosis. RESULTS: The largest area under the ROC curve was found for OCT inferior quadrant thickness (0.91 for diagnosis based on SAP, 0.89 for diagnosis based on disc appearance), followed by the FDT number of total deviation plot point of 5% (0.88 and 0.87, respectively), SLP linear discriminant function (0.79 and 0.81, respectively), and SWAP PSC (0.78 and 0.76, respectively). For diagnosis based on SAP, the ROC curve area was significantly larger for OCT than for SLP and SWAP. For diagnosis based on disc appearance, the ROC curve area was significantly larger for OCT than for SWAP. For both diagnostic criteria, at specificities of 90% and 70%, the most sensitive OCT parameter was more sensitive than the most sensitive SWAP and SLP parameters. For diagnosis based on SAP, the most sensitive FDT parameter was more sensitive than the most sensitive SLP parameter at specificities of 90% and 70% and was more sensitive than the most sensitive SWAP parameter at a specificity of 70%. For diagnosis based on a disc appearance specificity of 90%, the most sensitive FDT parameter was more sensitive than the most sensitive SWAP and SLP parameters. At a specificity of 90%, agreement among instruments for classifying eyes as glaucomatous was poor. CONCLUSIONS: In general, areas under the ROC curve were largest (although not always significantly so) for OCT parameters, followed by FDT, SLP, and SWAP, regardless of the definition of glaucoma used. The most sensitive OCT and FDT parameters tended to be more sensitive than the most sensitive SWAP and SLP parameters at the specificities investigated, regardless of the diagnostic criteria.

Dr C. Bowd, Glaucoma Center, Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA

Classification:

2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
6.6.3 Special methods (e.g. color, contrast, SWAP etc.) (Part of: 6 Clinical examination methods > 6.6 Visual field examination and other visual function tests)
6.9.1 Laser scanning (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis)

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