Ultraviolet Riboflavin-induced Cross-linker Design

Keratoconus is a kind of bilateral and progressive keratopathy,which is characterized by the central or paracenter of the cornea protruding forward and accompanied by corneal thinning.If not treated in time,it will cause irregular astigmatism and deepen myopia of the patient,and even lead to blindness when it reaches a certain stage.Corneal crosslinking is the only method that can control the development of keratoconus disease.However,at present,there is almost no research on the uv induced riboflavin crosslinking instrument for the treatment of keratoconus diseases in China,and all the instruments on the market are imported.It is of great significance to break the monopoly of this instrument in foreign countries and reduce the purchase cost of this kind of instrument and develop the uv-induced riboflavin crosslinking instrument(corneal crosslinking instrument)belonging to China.The main work of this paper can be divided into the following points: Based on the functional parameters and relative advantages and disadvantages of the uv-induced riboflavin crosslinking instrument in the market,the overall design scheme of the instrument was given by referring to the structure of the projector.By comparing several kinds of uv light sources,the advantages of uv LED as the light source of corneal crosslinking instrument are analyzed.The working principle of the key components of the instrument which named DMD and the technique of grayscale modulation are introduced.This paper introduces the characteristics of the image side telephoto lens in the aspect of illumination.The principle and method of the double eye lens and the equalizing tube are introduced.Based on the principle of the double eye lens,the DMD equalizing light path is designed,The homogeneity of the plaque reached 92%.Based on the principle that the illuminance of the image square and far center optical system is the maximum on the focal plane of the image plane,an ultraviolet projection lens with a working distance of 150 mm and a magnification of =-0.345 is designed to ensure the safety of the cornea during corneal crosslinking.The pupil location algorithm was designed based on the sliding arc length increasing wheel pupil center positioning method,and the idea of pupil center tracking based on point-by-point comparison method was introduced.The two algorithms mentioned above could ensure that the uv induced riboflavin cross-linking instrument could still project the treatment spot to the treatment area correctly when the intraoperative eye rotation of patients.Finally,the prototype is built and tested.The test results show that the functional parameters of the prototype designed in this paper completely meet the design requirements.