An article of manufacture comprises an optical shade configured for removable attachment to eyewear, e.g., eyeglasses that are retrofitted to include a micro-fluidic tear collector in a nose pad. The optical shade comprises a lens having a lateral flow assay comprising an antibody having an associated fluorescent tag. The fluorescent tag is configured to fluoresce and change a color of the lens upon detection by the flow assay of an antigen that matches the antibody. The antigen comprises viral constituents, such as SARS-CoV-2. The color change of the lens is visible and indicates presence of Covid-19 infection.