Attachment methods for daylighting sheets and a resulting optical construction enable daylighting microstructures to be secured to a light incident surface, such as a glazing. Applying an adhesive to selected portions of the daylighting microstructures creates a transparent, optical adhesive surface that enables the daylighting microstructures to be oriented outward, facing the incident light, and effectively seals the microstructures against the glazing to prevent ingress of dust and contaminants that would degrade optical efficiency.