Definitions of Fast Progression in Glaucoma Literature

Fast glaucoma progression is generally defined using numerical cut-offs applied to the rate of progression. However, no consensus guidelines exist for standardized thresholds, and multiple methods are used to estimate progression rates. We systematically review how fast progression is defined in the glaucoma literature and quantify heterogeneity in criteria, analytic methods, and structural or functional parameters used across studies.

Potential heterogeneity in defining fast glaucoma progression may influence reported prevalence, risk factor associations, and interpretation of outcomes across studies.

A systematic review (PROSPERO: CRD42024502764) was conducted using MEDLINE and Embase to identify studies assessing fast glaucomatous progression based on visual field (VF) examination, optic disc photography, OCT, confocal scanning laser tomography (CSLT), and OCT angiography (OCT-A). Childhood glaucoma was excluded. Two independent reviewers selected eligible studies and extracted complete definitions of fast progression.

Of 31 856 records identified, 122 met the eligibility criteria, yielding 88 definitions of fast progression, including 66 unique criteria and 16 analytic methods. The most frequent definition was mean deviation (MD) rate < -1.0 dB/year calculated using ordinary least squares regression (OLSR) (13 studies, 10.7%). Among structural definitions, the most common was global peripapillary retinal nerve fiber layer thickness decay ≥90th percentile of the study sample using OLSR. When analyzed separately, MD rate < -1.0 dB/year was the most commonly used measure (25 studies, 20.5%) and OLSR the most frequent analytic method (79 studies, 64.8%). Visual field testing was used in 103 studies (84.4%), OCT in 25 (20.5%), and CSLT and OCT-A in 1 study each (0.8%). Seven studies (5.7%) combined VF with a structural device (6 with OCT and 1 with CSLT), and 1 study combined OCT and OCT-A. Among VF-based studies, 3 (2.9%) used central testing (10-2), while among OCT-based studies, 4 (16.0%) focused on macular parameters. Mean deviation was the most frequently adopted index (81 studies, 66.3%), followed by peripapillary retinal nerve fiber layer thickness (21 studies, 17.2%).

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Definitions of fast glaucomatous progression in the literature are predominantly VF-based but vary widely in terms of indices, analytic model, and threshold used. Further research should clarify how different definitions influence fast progressor classification.