Paracentral scotoma in glaucoma detected by 10-2 but not by 24-2 perimetry

To describe, in glaucomatous patients, spectral-domain optical coherence tomography (SD-OCT) results predictive of paracentral visual field (VF) defects present on standard automated perimetry (SAP) 10-2, but not on SAP 24-2.

The SAP 10-2 test was repeated 3 times to determine whether paracentral VF defects were present. Spectralis™ HRA + OCT was used to obtain speckle-noise-reduced macular B-scans. The macular scan protocol consisted of 19 vertical cross-sectional scan lines centered on the fovea (30° × 15° volume scan), each of which was the average of 50 scans. A 3D OCT-2000 was also used to determine macular layer thicknesses and to detect abnormally thin regions (below the 1 % confidence interval of the normative data).

We identified 3 cases in which paracentral VF defects were detected on SAP 10-2, but not on SAP 24-2. Paracentral VF defects were detected on all of the SAP 10-2 tests repeated 3 times, and included absolute scotoma in 2 of the 3 SAP 10-2 results. Retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) damage was diminished on SD-OCT macular images; 2 patients had RNFL and GCL thinning within and central to the parafoveal region, where the GCL is generally thickest in healthy eyes, and 1 patient had evident RNFL and GCL thinning in the papillomacular bundle.

Macular SD-OCT scans may be useful in deciding whether SAP 10-2 should be performed.