Progress toward the establishment of nuclear magnetic resonance measurements as an index of in vivo lens functional integrity.

Cataract prevention, delay, or reversal requires in vivo detection of lens changes that initiate the opacification process. The determination of lenticular biochemistry by a noninvasive methodology would represent a major step in the in vivo assessment of lens normalcy. Nuclear magnetic resonance spectroscopy appears to be a promising noninvasive technique to meet this goal. However, the correlation of lenticular "invasive" morphological and physiological data with NMR spectroscopic data in organ culture is necessary for establishing the validity of NMR spectral measurements as an index of lens functional integrity. The implementation of lenticular NMR spectroscopic studies will provide quantitative information such as intralenticular pH, Na+ and K+ ion distributions, lenticular levels of phosphorus-containing metabolites, glycolytic pathway intermediates and the end product lactate, sorbitol pathway activity, and possibly reduced glutathione levels. Development in surface coil NMR spectroscopy which enables the spatial localization of tissue metabolites and advances in the refinements required for quantitation of these results are discussed. These measurements of in vivo lenticular biochemistry will provide the information necessary for the scheduling of anticataract drug therapy as well as an ongoing method for monitoring the efficacy of such treatment.