Utility of the Modified Isolated-check Visual Evoked Potential Technique in Functional Glaucoma Assessment.

PRE[COMBINING ACUTE ACCENT]CIS:: Cortical response to low-contrast stimuli, as measured by isolated-check visual evoked potential (icVEP) technology, has the potential to provide functional assessment that may complement standard achromatic perimetry in assessing glaucomatous change. PURPOSE: To evaluate the utility of modified icVEP testing in detecting functional glaucomatous damage. MATERIALS AND METHODS: Subjects who met predetermined criteria of controls, glaucoma suspects, preperimetric glaucoma, or glaucoma were enrolled in this prospective cross-sectional study from a single tertiary care center. Glaucoma patients were further categorized as early, moderate, advanced, or severe on the basis of Hodapp-Anderson-Parrish criteria. icVEP testing was performed with ten 2-second runs per qualified eye using the EvokeDx testing software. Multivariate statistics were used to calculate signal-to-noise ratios (SNR) and perform outlier analysis. RESULTS: In total, 140 eyes met criteria (mean±SD; age of 63±14 y; 49% male; logMAR visual acuity, 0.11±0.089). There was no significant difference in age, sex, or logMAR visual acuity among the groups. Controls had a significantly higher SNR than all other groups (P<0.003), including patients with preperimetric glaucoma. Among those with glaucoma, the early glaucoma patients had significantly higher SNR than the moderate, advanced, or severe glaucoma cohorts (P<0.04). The optimal SNR cutoff for differentiating between glaucomatous and nonglaucomatous eyes was 0.95, both with (sensitivity 82%, specificity 76%) and without (sensitivity 82%, specificity 100%) glaucoma suspects included in analysis. CONCLUSIONS: icVEP technology has the potential to complement standard achromatic perimetry in functional assessment of glaucomatous defects.

Within-subject assessment of foveal avascular zone enlargement in different stages of diabetic retinopathy using en face OCT reflectance and OCT angiography.

Enlargement of the foveal avascular zone (FAZ) due to progressive capillary nonperfusion is associated with visual deterioration in patients with diabetic retinopathy. The FAZ area has long been considered an important clinical marker of advancing retinopathy. However, a large body of literature shows that the FAZ area varies considerably in healthy eyes, resulting in substantial overlap between controls and diabetics, thus reducing its discriminatory value. In this study, within-subject FAZ area enlargement was obtained by the comparison of the structural FAZ area to the functional FAZ area using simultaneously-acquired, corresponding en face OCT reflectance and OCT angiography images. Our study suggests that en face OCT reflectance images provide useful anatomic baselines of structural FAZ morphology prior to the onset of disease. Measurements of within-subject FAZ area enlargement appear to be a more sensitive method for identifying the onset of diabetic retinopathy as compared to using OCT angiographic measurements of FAZ alone.