OCT Patterns Linked to Glaucoma Progression Vary by Stage

Key Takeaways

• Among glaucoma suspects assessed with wide-field OCT and subsequent visual-field testing, greater bihemiretinal-loss expression was significantly associated with progression.
• In early glaucoma, greater expression of early superior-loss and bihemiretinal-loss patterns was associated with visual-field progression.
• In moderate-to-advanced glaucoma, less normal-pattern expression and more superior hemiretinal-loss expression were associated with progression.
• Progression classifications across the visual-field criteria were substantially discordant.

In glaucoma and suspected glaucoma, which baseline wide-field swept-source optical coherence tomography (SS-OCT) patterns correspond to later 24-2 visual-field change across disease stages? Baseline retinal structure and subsequent visual-field change offer different views of the same clinical course.

Investigators performed an observational wide-field swept-source OCT archetype analysis of 1,803 SS-OCT scans, each from a different eye, across 1,167 patients with glaucoma or suspected glaucoma. Archetypal analysis identified representative structural patterns, each termed an archetype (AT). The researchers used fuzzy c-means to calculate decomposition coefficients describing how much each archetype contributed to an eye's imaging pattern. This allowed them to examine mixtures of patterns rather than assign each eye exclusively to one structural category.

The progression assessment included 372 eyes with at least five reliable 24-2 visual-field tests. Investigators examined whether baseline archetype expression was associated with subsequent visual-field progression, classified separately by mean deviation slope, Visual Field Index slope, and pointwise linear regression. None of these definitions was designated a reference standard.

The imaging analysis yielded 10 distinct structural archetypes. Among glaucoma suspects, greater baseline AT9 (bihemiretinal loss) expression was significantly associated with subsequent visual-field progression. In early glaucoma, greater AT4 (early superior loss) and AT9 expression were associated with progression. In moderate-to-advanced glaucoma, lower AT1 (normal) and greater AT5 (superior hemiretinal loss) expression were associated with progression. Across the visual-field criteria, 4.3% of eyes fulfilled all three progression definitions, while 81.7% fulfilled none.

Associations between baseline structure and later visual-field change do not demonstrate that monitoring guided by these patterns improves patient outcomes. Disagreement among progression classifications does not establish which criterion most accurately captures change. Although the structural patterns may be clinically interpretable, the proposed monitoring application has not been shown to benefit patients.

According to the authors, the structural patterns associated with visual-field progression depended on disease stage and the progression definition used; personalized monitoring remains a possible application.

Clinician Questions

Does meeting none of the 24-2 visual-field progression criteria rule out glaucoma?

No. Meeting none means that the evaluated definitions did not classify the eye as progressing; those definitions concern visual-field change, not whether glaucoma is present.

Can wide-field OCT archetypes independently predict progression in an individual glaucoma eye?

An AUC of 0.792 was reported for one archetype in glaucoma suspects, but it hasn’t been validated externally and no accuracy figures were given for individual-eye prediction in other stages.