Abstract
Purpose:
Glaucomatous damage to the macula (central ±10°) is relatively common and involves both deep local and shallow widespread defects.[1,2] To assess the extent to which macular damage can be missed and/or underestimated by a 24-2 visual field (VF) test, we examined various metrics of the 24-2 VF of patients with confirmed macular damage based upon 10-2 VFs and optical coherence tomography (OCT).
Methods:
108 eyes of 108 patients, either glaucoma suspects (abnormal disc and normal 24-2 VF) or patients with mild damage (abnormal disc and abnormal 24-2 VF with mean deviation (MD) better than -6 dB) were included. In addition to 24-2 VFs, all had 10-2 VFs and frequency-domain OCT cube scans of the macula (3D-OCT2000, Topcon). To be reasonably certain of the presence or absence of macular damage, an eye was considered abnormal only if the OCT macular retinal ganglion cell and/or retinal nerve fiber probability plots showed an abnormality in a region that corresponded to a defect seen on the 10-2 VF total deviation plot. Similarly, an eye was considered healthy only if both the OCT and 10-2 VF plots were normal. The 24-2 VFs of these eyes were assessed with commonly employed criteria: MD (<5%), pattern standard deviation (PSD< 5%), glaucoma hemifield test outside normal limits (GHT ONL), cluster criteria (CC: 3 neighboring points at 5, 5, and 1% or 5, 2, and 2% or worse within a hemifield) and macular points (points within ±10°: one at 1% or 2 at 2%).
Results:
Based upon the 10-2 VF and OCT plots, the macula was classified as abnormal in 48 eyes and healthy in 28. Of the 48 abnormal eyes, the 24-2 VF incorrectly identified (false negative): 17 (MD), 10 (PSD) 15 (GHT), 10 (PSD or GHT), 13 (CC), and 18 (±10° points). Thus, none of the criteria showed a sensitivity better than 79.2%. Additionally, in 4 of the abnormal eyes, the MD of the 10-2 VF exceeded the MD of the 24-2 by more than -3 dB. Of the 28 eyes judged healthy, the 24-2 VF incorrectly identified (false positive): 3 (MD), 6 (PSD), 2 (GHT), 6 (PSD or GHT), 13 (CC), and 5 (±10° points).
Conclusions:
The 24-2 VF missed over 20% of the eyes with macular damage confirmed on 10-2 VF and OCT scans. To reliably detect macular damage, 10-2 VFs (or a modified 24-2)[3] and OCT macular cube scans are essential.<br /> 1. Hood, Raza et al. (2013) PRER; 2. Hood, Slobodnick et al. (2014) IOVS; 3. Ehrlich et al. (2014) TVST.