Customized anterior segment photoacoustic imaging for ophthalmic burn evaluation in vivo

Photoacoustic imaging has many advantages in ophthalmic application including high-resolution, requirement of no exogenous contrast agent, and noninvasive acquisition of both morphologic and functional information. However, due to the limited depth of focus of the imaging method and large curvature of the eye, it remains a challenge to obtain high quality vascular image of entire anterior segment. Here, we proposed a new method to achieve high quality imaging of anterior segment. The new method applied a curvature imaging strategy based on only one time scanning, and hence is time efficient and more suitable for ophthalmic imaging compared to previously reported methods using similar strategy. A custom-built photoacoustic imaging system was adapted for ophthalmic application and a customized image processing method was developed to quantitatively analyze both morphologic and functional information in vasculature of the anterior segment. The results showed that the new method improved the image quality of anterior segment significantly compared to that of conventional high resolution photoacoustic imaging. More importantly, we applied the new method to study ophthalmic disease in an in vivo mouse model for the first time. The results verified the suitability and advantages of the new method for imaging the entire anterior segment and the numerous potentials of applying it in ophthalmic imaging in future.