Evaluation of photographic methods for documentation of lens opacities.

Several systems have been developed to document lens opacities photographically. In general, the settings for these photographs have been standardized, but there has been no scientific basis for the selection of these settings. We investigated several of these variables. We examined the effect of degree of angulation of the slit beam in slit photography of the nucleus and found no difference in the grading of nuclear opacities in paired photographs taken with illumination angles of 30 or 40 degrees. Similarly, we found no difference between black-and-white and color film in the detection or grading of either cortical or posterior subcapsular opacities in retroillumination photographs and no difference if a Neitz or an Oxford cataract camera was used. In view of the equivalence of these methods, we would advocate, for reasons of ease of application and cost, the use of a single-color slit-lamp photograph with a 30 degree slit angle for documenting nuclear opacities, and the use of black-and-white retroillumination photography with either the Neitz or Oxford cataract cameras for cortical and posterior subcapsular opacities.