Imaging and documentation of the human retina for clinical diagnostics are conventionally achieved by classical optical methods. We designed a digital laser scanning fundus camera. The optoelectronical instrument is based on scanning laser illumination of the retina and a modified video imaging procedure. It is coupled to a digital image buffer and a microcomputer for image storage and processing. Aside from its high sensitivity the LSF incorporates new ophthalmic imaging methods like polarization differential contrast. We give design considerations as well as a description of the instrument and its performance.
Safety standards such as American National Standards Institute Z-136.1 do not give clear light-level limitations for laser scanning ophthalmoscopes. To have more than a rough estimation the retinal temperature rise due to intraocular scanning laser illumination was calculated on the basis of a thermal model. The predicted temperature development with time was compared with the calculated effect of other retinal illumination patterns with well-known hazard risks. The similarity of the thermal effect of retinal scanning and extended-source pulsed illumination is discussed and used to give maximum permissible light-level recommendations for the safe use of laser scanning ophthalmoscopes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.