## Risk Assessment in Narrow-Angle Eyes **Key Point:** Anterior segment OCT (AS-OCT) is the non-contact, reproducible imaging modality of choice for quantifying angle dimensions and assessing closure risk in asymptomatic narrow-angle eyes. ### AS-OCT in Narrow-Angle Assessment AS-OCT provides: - **Quantitative measurements** of angle opening distance (AOD), trabecular-iris space area (TISA), and angle-opening distance at 500 µm (AOD500) - **Reproducibility** — enables serial monitoring over time - **Non-contact imaging** — safe for acute angle-closure and sensitive corneas - **Risk stratification** — helps identify eyes at highest risk of progression to acute attack ### Comparison of Angle Assessment Modalities | Modality | Strengths | Limitations | |----------|-----------|-------------| | **AS-OCT** | Quantitative, reproducible, non-contact, high resolution | Requires clear media | | **Gonioscopy** | Direct visualization, gold standard for diagnosis | Subjective, contact, difficult in acute settings | | **UBM** | High resolution, dynamic imaging, works in hazy media | Operator-dependent, contact, time-consuming | | **Specular microscopy** | Endothelial cell assessment | Does NOT assess angle anatomy | **High-Yield:** AS-OCT measurements correlate with gonioscopic findings and predict angle-closure risk: - AOD500 < 250 µm → high risk - TISA < 0.05 mm² → high risk - Serial AS-OCT can track angle narrowing trends **Clinical Pearl:** In asymptomatic narrow-angle eyes, AS-OCT helps distinguish those requiring urgent prophylactic iridotomy from those suitable for observation and periodic monitoring. **Mnemonic — ASOCT:** **A**nterior **S**egment **OCT** quantifies angle opening distance, trabecular-iris space area, and risk. 
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