Evaluation of macular thickness measurements for detection of band atrophy of the optic nerve using optical coherence tomography.

PURPOSE

To evaluate the ability of optical coherence tomography (OCT) macular thickness parameters to differentiate between eyes with band atrophy (BA) of the optic nerve and healthy eyes.

DESIGN

Cross-sectional study.

PARTICIPANTS

The study included 1 eye of each of 40 consecutive patients with BA of the optic nerve and permanent temporal hemianopic visual field (VF) defects owing to chiasmal compression and 31 age- and gender-matched healthy subjects.

METHODS

All patients underwent VF assessment with kinetic Goldmann perimetry and Humphrey 24-2 full-threshold standard automated perimetry (SAP). Macular and retinal nerve fiber layer (RNFL) thickness scans were obtained using the commercially available Stratus OCT. The severity of VF defect in patients with BA was evaluated by the temporal mean defect (TMD), calculated as the average of the 22 values of the temporal total deviation plot of the SAP 24-2 test, excluding the 2 points immediately above and below the blind spot.

MAIN OUTCOME MEASURES

Receiver operating characteristic (ROC) curves and sensitivities at fixed specificities were calculated for each parameter. Spearman's rank correlation coefficients were used to evaluate the relationship between RNFL and macular thickness parameters and severity of VF loss as measured by the TMD.

RESULTS

The macular thickness parameters related to the nasal hemiretina had the best performance to detect damage in BA eyes. No statistically significant difference (P = 0.19) was found between the ROC curve areas (AUCs) for the best macular thickness parameter (temporal/nasal macular thickness, AUC = 0.96) and the best RNFL parameter (average thickness, AUC = 0.99). Lower values of TMD, indicating more severe VF loss, were associated with lower macular thickness measurements. The highest correlation was observed for the parameter nasal average macular thickness (rho = 0.693, R2 = 48%, P<0.001).

CONCLUSION

Eyes with BA of the optic nerve show significant thinning of the retinal thickness on the nasal macular area, which is associated with the severity of VF damage in these eyes. Macular thickness measurements could potentially be used to evaluate the amount of ganglion cell loss in patients with BA of the optic nerve and could prove clinically useful for detection of damage and for monitoring these patients.