Comparative analysis of central versus peripheral visual field test grids in the diagnosis of glaucoma

Accumulating evidence has recognised central visual field defects (CVFDs) as a common feature of glaucoma. Current glaucoma screening guidelines include peripherally biased perimetry (24-2 protocols), but test grids exist to test the integrity of the central visual field (10-2 protocols). However, the added benefit of incorporating central visual field assessments alongside peripheral-biased testing grids remains unclear. This scoping review aimed to compare the diagnostic accuracy of central versus peripheral visual field tests. A systematic search of six databases yielded relevant studies among glaucoma subjects. These studies were synthesised narratively, focusing on diagnostic performance indicators such as the area under the curve, sensitivity, specificity, diagnostic agreement, and structure-function concordance. Of the 1875 studies screened, 16 were included in the review. The comparative analyses demonstrated a similar diagnostic performance when comparing the ability of the 24-2 and 10-2 test grids to detect glaucoma or CVFDs. When utilising the mean deviation, the 24-2 area under the curve ranged between 0.81-0.87 and 0.74-0.84 for the 10-2, whilst the area under the curve of the pattern standard deviation was 0.95 and 0.82, respectively. The pattern standard deviation showed sensitivities reaching 0.75 for the 24-2 and 0.60 for the 10-2, with specificities as high as 0.95 for both test grids. Across all disease stages, CVFDs detected on the 24-2 demonstrated up to 88% agreement with functional damage detected on the 10-2. The agreement between structure-function damage was greatest when combining test grids with optical coherence tomography (88.7%). This review indicates that the 24-2 and 10-2 testing protocols offer comparable diagnostic performance for glaucoma, including detecting CVFDs. While targeted macula screening could provide additional diagnostic value in certain contexts, the evidence remains inconclusive. Further longitudinal studies, incorporating optical coherence tomography, are necessary to confirm these findings and consider the routine inclusion of CVFD screening in clinical practice.