Fabrication of healthy and disease-mimicking retinal phantoms with tapered foveal pits for optical coherence tomography.

Optical coherence tomography (OCT) has become a standard tool in ophthalmology clinics for diagnosing many retinal diseases. Nonetheless, the technical and clinical communities still lack a standardized phantom that could aid in evaluating and normalizing the many protocols and systems used for diagnosis. Existing retinal phantoms are able to mimic the thickness and scattering properties of the retinal layers but are unable to model the morphology of the foveal pit, particularly the tapering of the retinal layers. This work demonstrates a new fabrication procedure that is capable of reliably and consistently replicating the shape and tapered appearance of the retinal layers near the foveal pit using a combination of spin-coating and replica molding. We characterize the effects of using different mold sizes which enable us to achieve a range of pit dimensions. We also present a modified procedure to replicate two diseased states of the retinal tissue, such as retinal detachment and dry aged-related macular degeneration. The ability to create an anatomically correct foveal pit for healthy and disease-mimicking phantoms will allow for a new standard better suited for intra- and inter-system evaluation and for improved comparison of retinal segmentation algorithms

Effect of polarization on a solid immersion lens of arbitrary thickness.

A solid immersion lens can be applied for high-resolution subsurface analysis of integrated circuits and other physical systems. We present a thorough analysis of the focal field distribution of a solid immersion lens system of arbitrary thickness. Cases of linearly and radially polarized illumination are examined and accurate expressions derived for the electric field in the image space. The effect of the spherical interface on both transverse and axial intensity profiles is analyzed. The performance and practicality of configurations deviating from the hemispherical and aplanatic cases are studied. The results show that optimal resolution is obtained at focal positions between the hemispherical and aplanatic points when radially polarized illumination is applied.