Optic Disc Structural Progression in Glaucoma Suspect Eyes With Microvascular Dropout

To investigate the relationship of structural progression, β-zone parapapillary atrophy (PPA) progression, and microvascular dropout (MvD) in glaucoma suspect eyes.

Retrospective cohort study.

Eyes were included if optic disc photographs were available at least 5 years before optical coherence tomography angiography imaging. During follow-up, structural progression and β-zone PPA progression were recorded. Structural progression was graded using stereophotographs; eyes were classified as progressing if new or enlarged retinal nerve fiber layer defects or neuroretinal rim thinning were detected. β-zone PPA was quantified (area, radial width, angular extent), with progression defined as a ≥20% increase in any parameter. The presence of MvD at the last visit was evaluated using en-face choroidal vessel density maps. Multivariable logistic regression was used to assess the association between MvD and structural progression, adjusting for covariates and β-zone PPA progression. Margins analysis was performed to estimate predicted probabilities of structural progression by MvD status and β-zone PPA progression.

A total of 180 eyes from 134 glaucoma suspect patients were included, of which 58 eyes (32.2%) had MvD. The mean follow-up duration for fundus photographs was 19.0 (95% CI, 17.9-20.1) years. The presence of MvD and also β-zone PPA progression were significantly associated with structural progression (15.8 [95% CI, 5.6-44.6], P < .001; 3.8 [95% CI, 1.2-11.7], P = .022, respectively). Margin plots indicated that eyes exhibiting both MvD and β-zone PPA progression had the highest estimated probability of structural progression (0.75).

In glaucoma suspect eyes, the presence of both MvD and β-zone PPA progression were independently associated with structural optic disc progression. These structural changes were observed in glaucoma suspect eyes that remained clinically stable and did not convert to perimetric glaucoma during the period of observation in this study. Recognition of these changes may enhance more timely management to prevent glaucomatous vision loss.