CLINICAL SCIENCES Detection of Psychophysical and Structural Injury in Eyes With Glaucomatous Optic Neuropathy and Normal Standard Automated Perimetry

Methods: Complete examination, SAP, shortwavelength automated perimetry (SWAP), frequency doubling technology (FDT), scanning laser polarimetry (GDx-VCC), and optical coherence tomography (OCT) of the peripapillary retinal nerve fiber layer (RNFL), optic disc, and macula were performed. Glaucomatous optic neuropathy was defined as cup-disc asymmetry between fellow eyes of greater than 0.2, rim thinning, notching, excavation, or RNFL defect. All eyes had normal SAP. Abnormal measurements on OCT, GDx-VCC, SWAP, and FDT were defined as those outside 95% normal limits. Eyes were stratified into 3 groups based on the OCT-generated vertical cup-disc ratio: mild, moderate, and advanced cupping (cup-disc ratio of 0.4, 0.4-0.7, and 0.7, respectively). Receiver operating characteristic curves were developed to assess sensitivity and specificity of structural and functional assessments. Results:Forty-seveneyesof47patients (25withGONand 22 normal) were enrolled (mean ± SD age, 58 ± 16 years; range,25-83years).Comparedwithnormaleyes, eyeswith GON had significantly worse mean deviation and pattern standarddeviationbymeansofSWAPandFDT(P=.02-.05); OCT-derived mean and superior and inferior RNFL thickness (P=.008, .001, and .05, respectively); mean macular thickness (P=.01), rimvolume, rimarea, cup-disc ratio, and cup area (all P .001); and GDx-VCC nerve fiber indicatorandinferioraverage(P=.03).Therewasasignificantly (P=.008, .002, .003,and.01,respectively)greaterprevalence of abnormalities identified by SWAP, FDT, OCT and GDxVCC in eyes with advanced cupping (43%, 43%, 57%, and 57%, respectively) compared with mild cupping (0%) and moderate cupping (9%, 5%, 19%, and 33%, respectively).