Development of a Scheimpflug slit lamp camera system for quantitative densitometric analysis.

We have developed a computerised video system for accurate quantification of lens opacities from Scheimpflug images. Using a modified Zeiss Scheimpflug camera and Macintosh computer, the system software can warn of improper exposure and can provide immediate results of cataract progression on individual patients. These results are obtained from a novel technique which automatically divides the lens into anatomical regions and computes regional densities in the standard optical density unit. Because of the system's speed, the operator can properly capture and analyse a cataract in seconds, compare results with past patient records and give feedback to the patient on the results of the analysis. The system provides the appropriate data integrity and formats for documenting and monitoring lens opacities. Such a system will be useful in longitudinal studies of cataracts (i.e. for natural history and anti-cataract drug trials).