设计了一款大视场、免散瞳便携式眼底相机。综合考虑接目物镜被成像和照明系统共用、人眼的像差和视度差异等因素，采用16重结构进行优化设计。设计结果的视场角达60°，分辨率为200万像素，对-8 D~+10 D(1 D=1 m-1)的人眼普遍适用，在120 lp/mm处各视场的调制传递函数(MTF)均大于0.2，畸变小于5%。为消除角膜反射产生的严重杂散光，提出采用LED环形光源改进传统科勒式照明光路，不仅保证眼底照明均匀，而且大大提高了系统的光能利用率，降低了光学系统的复杂程度。为了解决传统系统中接目物镜杂散光无法消除的难题，提出采用偏振分光棱镜代替系统中的分光镜，同时在接目物镜前端加入λ/4波片，消除了99.5%以上的由接目物镜反射产生的杂光。

A novel portable free-dilated fundus cameras with large field of view (FOV) is designed. By taking consideration of human eye′s aberration and vergence, as well as the sharing of the eye-piece objective lens between the illumination system and the imaging system, a lens system with 16 configurations is set up for optimization. As a result, an FOV of 60° and 2 mega pixels resolution have been achieved. The camera can be adapted to eyes in which vergence ranges from -8 D to +10 D; the modulation transfer function (MTF) values of all fields are higher than 0.2 at 120 lp/mm with distortion less than 5%. In order to eliminate the stray light reflected by cornea, ring-shaped LED light source is used to replace traditional Kohler illumination system. The method not only ensures illumination uniformity on fundus, but also greatly improves illumination efficiency and dramatically simplifies the system. A polarizing beam splitter (PBS) and a quarter-wave retarder are used to replace the traditional beam splitter and the black dot board for the first time to shield the stray light. 99.5% of the stray light caused by the eye-piece objective lenses is eliminated.