Dynamic Light Scattering for Studying Lens Aging and Cataract Formation

This study will use dynamic light scattering (DLS) technology to study normal lens aging and early cataract formation. Cataract is a clouding of the lens that interferes with the passage of light to the retina, impairing visual acuity. DLS uses a low intensity laser light (similar to that used in supermarket checkouts) to measure lens cloudiness. It detects changes in the human lens at the earliest molecular stages of cataract development, when anti-cataract treatment would be most effective in reversing, delaying or preventing cataract formation.

Healthy normal volunteers and patients with age-related cataract between 18 and 80 years of age may be eligible for this study. Participants undergo the following tests and procedures:

Medical history

Eye examination, including the following:

• Measurement of visual acuity (vision chart)
• Measurement of eye pressure
• Dilation of the pupils for slit lamp (microscope) examination and grading of lens opacity
• Ultrasound examination of the eye to determine distances between cornea, lens (including lens thickness), and retina
• Examination of the retina at the back of the eye
• Dynamic light scattering of the lens (see below)
• Lens photography using a camera with a bright flash

For the DLS procedure, the patient sits in front of the DLS device with his or her chin placed on a chin rest and fixes on a yellow target in the center of the camera lens. When the eye is properly aligned, DLS measurements are taken on the lens.