Lens design with suppressed first order reflections

Optical systems with a reflected light condition, e.g. microscopes with reflected light illumination or fundus cameras, need to have weak first order ghosts or even to be completely free from them. Sequential ray tracing can be used to control optical performance and reflections on a ray basis during optimization. This is significantly more efficient in computation time and convergence than the usual approaches with non-sequential ray tracing or reconfigured optical systems to cover all critical ghosts. An ophthalmic lens for a fundus camera was designed with first order reflections stripped out by applying sequential ray tracing. The merit-function only had to be completed under certain conditions guaranteeing the absence of any reflections. No additional reconfiguration of the optical system in the design software was necessary.