Macular symmetry testing for glaucoma detection.

Purpose: To evaluate structural asymmetry in the macula using optical coherence tomography (OCT) in glauconiatous eyes with visual field defects localized to one hemifield. Methods: Complete examination, standard automated perimetry (SAP), and OCT imaging (512 A-scans) of the peripapillary retina and macula were performed. Exclusion criteria were visual acuity < 20/40, diseases other than glaucoma, and SAP defects localized to both hemifields. Macular OCT images were obtained using four 5-mm radial scans centered on the foveola and passing obliquely through the macula (15 degrees superotemporally and inferotemporally). Macular measurements temporal to the fovea (T) were sub-divided into nasal (T1) and temporal (T2) segments. Macular symmetry testing (MST) was performed in T, T1, and T2 segments by comparing the mean macular thickness of the perimetrically abnormal and perimetrically normal hemi-zones (macular thickness in perimetrically normal hemi-zone/macular thickness in perimetrically abnormal hemi-zone X 100), and superior and inferior hemi-zones in normal subjects (macular thickness in superior hemi-zone/macular thickness in inferior hemizone X 100). MST measurements were considered to be abnormal if they exceeded the 95% limits of normal variability. Conclusion: Localized macular thickness changes exist in glaucomatous eyes with regional visual field loss. The MST may represent a novel strategy for glaucoma diagnosis.