Investigation of the lower punctum parameters: A spectral domain anterior segment optical coherence tomography study

Purpose: To evaluate the dimensions of lower punctum in a sample of Iranian normal population using spectral domain anterior segment optical coherence tomography (OCT). Methods: In this cross-sectional study, 102 eyes of 102 healthy volunteers were enrolled. All participants underwent a detailed history and complete ophthalmic examination. Lower punctum metrics were measured using OCT (Spectralis, Heidelberg) with the anterior segment module. External punctal diameter was defined as the largest diameter at the surface of the punctum. Internal punctal diameter was measured at two different depths of 100 μm and 500 μm from the external surface. Measurements were repeated for 30% of data by another grader. The agreement was measured using intraclass correlation coefficient (ICC). Results: The mean age of the participants was 61.5 ± 7.9 years. The mean external punctal diameter was 425.6 ± 124.3 μm. The mean internal punctal diameter at 100 μm and 500 μm was 183 ± 97.5 μm and 77.7 ± 51.4 μm, respectively. The agreement between the graders was high in assessing all punctal characteristics (ICC >0.9 for all measurements). Conclusion: The spectral domain OCT can be used for measuring lower punctum diameter with acceptable reproducibility.