A low cost CMOS polarimetric ophthalmoscope scheme for cerebral malaria diagnostics

In this paper, we present a low cost CMOS polarimetric ophthalmoscope scheme enabling the capture of the retinal abnormalities that are unique to cerebral malaria. The proposed technology, which can be integrated into cellphones, offers the basis for quick and non-invasive screening of cerebral malaria. In addition, we report a high quality micropolarizer array for the proposed polarimetric ophthalmoscope, exploiting “guest-host” interactions in liquid crystals. With dichroic azodye-1 (AD1) molecules as the “guest” and nematic liquid crystal (NLC) molecules as the “host”, we demonstrate a better control of the molecular orientation of the “guest”, which in turn results in a ~25% increase of the major principal transmittance and a 139% increase of the peak extinction ratio. The proposed micropolarizer fabrication technology is simple and cost-effective, requiring only selective photo-patterning of a “guest-host” polymer spincoated over the image sensor.