Recent research suggests visual field (VF) testing with additional macular locations can modestly improve the identification of macular defects in glaucomatous optic neuropathy (GON) without loss of specificity when appropriate criteria are selected.
The prospective cross-sectional study evaluated 440 healthy controls and 499 GON patients with a fundus tracked perimeter using a 24-2 grid with 12 additional macular locations (24-2+). Macular defects were defined as locations with measurements outside the 5% and 2% normative limits on total deviation (TD) and pattern deviation (PD) maps within the central 10° of the VF.
At matched specificity, cluster detection identified more macular defects with the 24-2+ compared with the 24-2. For example, the mean increase in percentage of detection was 8% and 10% for the TD-5% and PD-5% maps, respectively, and 5% and 6% for the TD-2% and PD-2% maps, respectively. The researchers found that there was good agreement between the two grids. The improvement measured by partial areas under the detection curve was also significant but generally small.
Also of note:
The percentage of eyes with macular defects ranged from 30% to 50%.
Test time for the 24-2+ was longer (21% increase).
Between 74% and 98% of defects missed by the 24-2 had at least one location with sensitivity <20dB.
“The overall difference between the two grids is small,” the study authors concluded. “A more tailored approach, possibly based on structural evaluations, could help select people who are more likely to benefit from more precise macular testing.”
Montesano G, McKendrick AM, Turpin A, et al. Do additional testing locations improve the detection of macular perimetric defects in glaucoma? Ophthalmology. June 18, 2021. [Epub ahead of print].