Pilot Sudy on Normal and Diseased Corneas with the NASA-

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The transparent cornea, located in the front of the eye, acts not only as a refracting medium to focus light on the retina and help us see, but also serves as the main barrier and wall in the front of the eye. Serious disease of the cornea leads to opacification and blindness. Corneal diseases and injuries are the leading reason for visits to eye care clinics in the U.S. today. These diseases are also some of the most painful eye disorders. Two important areas for research on the cornea are: 1) to explore and understand the molecular basis of corneal transparency, and 2) to analyse the molecular nature of corneal wound healing and inflammation. We have developed a new clinical device to understand molecular changes that occur in the lens, the NASA-NEI Dynamic Light Scatering (DLS) device. Laboratory studies have shown its potential in the detection of the earliest changes occuring in cataracts. Clinical studies on the lens have also shown good test-retest reproducibility, sensitivity to pick up small changes, and safety of the non-invasive, in vivo DLS clinical system. We conducted laboratory studies in animals to determine if the DLS device is also useful to study the cornea. We found that it is also indeed useful in detecting molecular differences in various layers/compartments of the cornea in the normal state. In addition, we found that after corneal injury such as after laser photorefractive surgery, chemical injury and scraping, the DLS could detect changes which are not apparent or detectable using optical devices such as the slit lamp biomicroscope. Hence, the DLS also holds promise as a non-invasive, in vivo device to study the cornea in the normal state as well as in diseased states (such as after injury or surgery or in inherited genetic diseases), and in studies to understand the molecular basis of corneal transparency In this pilot project, we will study the normal cornea in young and older persons (volunteers) as well as cloudy, opaque corneas, as well as determine the safety and reproducibility of the device for corneal use. In preliminary testing, it was determined that the current DLS device used to study cataracts is not properly suited for the cornea. This is because of the difference in thickness between the cornea and the lens (0.5 mm in the human cornea versus 3-4 mmm in the human lens), so that the angle of entry of the Helium Neon Light beam versus the angle of the APD light detector is not correct. Hence a new NASA-NEI DLS device for the cornea needed to be made and is nearing completion.