Re: Arcus senilis - Why is there a clear space between it and its source please

Hi Steven, This is a really good question that would be best served by going to a health sciences library and looking up research journals in the area of Optometry or Ophthalmology. Unfortunately, I have no reference readily available that specifically answers your question. As a clinician, I know why arcus senilis occurs and when it is normal physiology vs. indication of high serum cholesterol/lipids. The exact mechanism of deposition in the corneal stroma I am not certain, and perhaps there are only theories at this point. One thing I can tell you is since the healthy cornea is avascular, cholesterol has to leak or diffuse out of capillaries at the limbus through some sort of passive transport (I would guess) system into the corneal stroma, which is filled with very neatly arranged bundles of collagen fibers which gives the cornea the unique characteristic of being transparent. Best of luck! Kenton L. McWilliams, O.D.