Tear meniscus measurement in nasolacrimal duct obstruction patients with Fourier‐domain optical coherence tomography: novel three‐point capture method

Purpose: Fourier‐domain optical coherence tomography (FD ODT) for the evaluation of marginal tear film has not been performed in patients with watery eye or in a controlled study. We used FD OCT to evaluate the height of the lower lid tear film at three points in normal adults and compared it with two watery eye groups. Methods: We prospectively evaluated with FD OCT 25 normal subjects and 44 patients with a watery eye. Twenty‐three patients with primary acquired nasolacrimal duct obstruction (PANDO) and 21 patients with functional nasolacrimal duct obstruction (FNLDO) were enrolled. Three images were obtained by three vertical FD OCT scans centred on the lower eyelid and inferior cornea, the medial limbus and the lateral limbus. The tear meniscus height (TMH), tear meniscus depth (TMD) and tear meniscus area (TMA) were measured with computer calipers and compared at three points between the two groups. Results: Watery eyes have significantly greater median TMHs at three points (medial: 584 μm, central: 592 μm, lateral: 470 μm) than controls (274, 291, 205 μm, p < 0.001). Medial and central TMHs were higher than lateral TMH in controls and watery eyes. TMD and TMA also increased significantly in watery eyes (p < 0.001). There was a significant increase in central TMH compared to medial TMH in FNLDOs than in PANDOs (p < 0.05). Conclusion: Fourier‐domain OCT is a valuable clinical tool in the evaluation of TMH in normal and watery eyes. TMH at three points can be a useful clinical parameter that investigates changes of lower tear meniscus pattern in both PANDO and FNLDO groups.