A new non invasive, in vivo technique to study the molecular changes in the human lens, called Dynamic Light Scattering Device (DLS), has recently been developed. Preliminary studies have shown its potential to detect the earliest changes in cataract, at the stage where anti-cataract treatment would be most effective in reversing, delaying or preventing cataracts. A new miniaturized version of this device has been developed by NASA using lower energy lasers, and under a NASA-NEI Inter Agency Agreement, has been successfully developed into a clinical device at the NEI. We recently conducted pilot studies to evaluate the usefulness and reproducibility of this instrument for quantitating human lens changes, and found good reproducibility. We also derived a useful parameter to use with this new technique, the log mean particle size, derived from particle size distribution data. Preliminary studies have also shown that the NASA-NEI DLS device can be used to detect and monitor molecular changes in early cataract formation as well as in normal aging. We therefore propose to conduct a larger cross sectional clinical study to detect and monitor molecular changes in the lens in early cataract formation and in normal aging.
INCLUSION CRITERIA: Patients aged 18-80 years will be admitted to this study. There will be no racial or gender bias in the recruitment. 227 patients with AREDS nuclear cataract grades 2 or less will be enrolled in the study. 40 patients with AREDS nuclear cataract grade 3 and 4 will also be enrolled. For those patients enrolled in the study, both eyes will be evaluated for this protocol. However, the participant has the right to choose to undergo measurements only in one eye. In that case, the eye to be examined will be determined by the partipantt's birth month. If the patient's birth month is an even number, the right eye will be examined; if the patient's birth month is odd, the left eye will be examined. EXCLUSION CRITERIA: Subjects who have tear film disorders, corneal opacities or disorders, uveitis, glaucoma or who have difficulty fixating, will be excluded. Subjects who are thought to be at risk for an adverse reaction to pupil dilation, or have a history of allergic reaction to one of the dilating agents that will be used, will be excluded.