Uncertainty-Gated Glaucoma Screening: Combining Semi-Supervised Classification with Multi-Agent Large Language Model Deliberation

Automated glaucoma screening from optical coherence tomography (OCT) faces two persistent challenges: scarcity of expert-labeled data and unreliable model predictions on diagnostically ambiguous cases. We present a two-tier diagnostic pipeline that addresses both. In the first tier, an EfficientNetV2-S classifier trained under a semi-supervised pseudo supervisor framework achieves 0.84 AUC on 150 held-out test patients from the Harvard Glaucoma Detection and Progression dataset, using only 350 labeled training samples out of 700. In the second tier, 124 flagged cases are routed to a multi-agent system built on MedGemma 4B, where three specialist agents deliberate over three rounds before rendering a final diagnosis. On these flagged cases, the agent system achieves 100% sensitivity—detecting all 55 glaucoma cases with zero missed diagnoses—and 89.5% overall accuracy (111/124), compared to the classifier’s 73.4% (91/124). Uncertainty analysis confirms that the classifier’s output probability reliably separates confident predictions (96.3% accuracy, n = 27) from uncertain ones (74.0%, n = 123), producing a 22-percentage-point gap that serves as a triage signal. The agents fix 32 cases the classifier misclassifies while introducing 12 new errors, yielding a net improvement of 20 cases. These results are from a single training run without variance estimates and should be interpreted as preliminary evidence that uncertainty-gated routing to vision-language model agents can meaningfully improve diagnostic accuracy on the cases where automated classifiers are least reliable.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This study did not receive any funding

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This study uses a publicly available, de-identified dataset (Harvard Glaucoma Detection and Progression dataset). No new data were collected and no identifiable human subjects were involved. https://ophai.hms.harvard.edu/code/harvard-gdp/

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