Infrared-based third and second harmonic generation imaging of cornea

The cornea functions as an optical lens and plays an important role in vision. For corneal diagnosis and treatment such as refractive surgery, a microscopic imaging system with a 3-D cellular resolution and retinal safety is strongly desired. Recently, confocal and multiphoton microscopies have been applied to corneal imaging with visible to near-infrared light sources. To increase retinal safety, an infrared light source is be needed. In this work, an infrared-based third and second harmonic generation microscopic study of mouse eyes is reported with ∼700-μm penetrability and high cellular resolution. This study provides a critical reference for future development of infrared-based corneal imaging.