Surface tracking integrated extended depth-of-field microscopy for rapid non-contact examination of conjunctival goblet cells in humans.

Conjunctival goblet cells (CGCs) are specialized epithelial cells playing key roles for ocular surface homeostasis, and their examination is important for diagnosing ocular surface diseases. Despite recent advancements in high-contrast CGC imaging for non-invasive examination, significant challenges remain for human applications. High-speed large-area imaging over the curved ocular surface is needed to assess statistically meaningful CGCs in the extensive human conjunctiva. To address this challenge, we developed a novel surface detection method and an integrated microscopy system for human use. With both a long detection range of 2 mm and a high update rate of 50 Hz, the surface detection method enabled real-time surface tracking during large-area imaging. The integrated microscopy could complete 5 × 2 patch imaging in approximately 10 s. CGC density analysis showed significantly reduced uncertainties with large-area imaging. This is the first demonstration of non-contact large-area cellular examination in humans, and this new development holds promise for non-invasive CGC examination and accurate diagnosis of ocular surface diseases.