Clinical Detection of Precataractous Lens Protein Changes Using Dynamic Light Scattering

Objective: To use dynamic light scattering to clinically assess early precataractous lens protein changes. Methods: We performed a cross-sectional study in 380 eyes of 235 patients aged 7 to 86 years with Age-Related Eye Disease Study clinical nuclear lens opacity grades 0 to 3.8. A dynamic light-scattering device was used to assess alpha-crystallin, a molecular chaperone protein shown to bind other damaged lens proteins, preventing their aggregation. The outcome measure was the alpha-crystallin index, a measure of unbound alpha-crystallin in each lens. The association of the alpha-crystallin index with increasing nuclear opacity and aging was determined. Results: There was a significant decrease in the alpha-crystallin index associated with increasing nuclear lens opacity grades (P<.001). There were significant losses of alpha-crystallin even in clinically clear lenses associated with aging (P<.001). The standard error of measurement was 3%. Conclusions: Dynamic light scattering clinically detects alpha-crystallin protein loss even in clinically clear lenses. alpha-Crystallin index measurements may be useful in identifying patients at high risk for cataracts and as an outcome variable in clinical lens studies.