This study will test the reliability of an instrument called the Quasi Elastic Laser
Scattering Device (QLS) in detecting early changes in cataract formation.
Surgery is currently the only treatment for cataracts. Many laboratories, however, are
researching drugs to reverse, delay or prevent cataract formation. Anti-cataract drugs
presumably would be most effective given early in the course of disease. When clinical
trials of these drugs are begun, dependable and standardized methods for documenting and
monitoring lens opacities will be needed to test their effectiveness. The QLS was designed
to detect the earliest molecular changes in cataract development. This study will evaluate
the usefulness and reliability of this instrument in measuring these changes.
Normal volunteers and patients with cataracts in this study will have a standard eye
examination, including a vision test and eye pressure measurement. The pupils will be
dilated for QLS testing and for examination of the retina. Photographs of the retina may be
taken. The QLS test uses a very dim laser light similar to that used to scan grocery items
in the supermarket. The laser beam is projected into the lens of the eye, and the scattered
light is collected and analyzed to determine normal and abnormal molecular interactions in
the lens. Two measurements will be done for each eye. The test will be repeated in 6
months to determine reproducibility of the system.
Recently, a device has been created to determine molecular interactions that occur in the
nucleus of the lens, called Quasi Elastic Laser Scattering Device (QLS). Preliminary
studies have shown its potential in the detection of the earliest changes occurring in
cataract, at the stage where anticataract treatment would theoretically be most effective in
reversing, delaying or preventing cataracts. A new miniaturized version of this device has
been developed by NASA using low energy lasers and offered for further development and
testing at the NEI. We therefore propose to conduct a preliminary study to evaluate the
usefulness and reproducibility of this instrument for quantitating lens changes.
Patients 18 years or older will be admitted to this study. There will be no gender or sex
bias in the recruitment.
Three subjects who are normal volunteers below age 40 and three subjects who are normal
volunteers above age 40 will be recruited. These normal volunteers should have clear
lenses with LOCS II clinical score for nuclear opalescence of 0.5 or less.
In addition, 3 subjects who have early nuclear cataract (LOCS II/Nuclear opalescence -2)
will also be recruited for the study.
QLS data will be obtained on each eye of the normal and cataractous subjects in the
No patients who have uveitis, glaucoma and 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.