This is a grayish-white ring-shaped fatty deposit near the limbus that can occur at any age but usually appears in advanced age (Fig. 5.14). Arcus senilis is usually bilateral and is a frequently encountered phenomenon. It occurs as a result of lipid deposits from the vessels of the limbus along the entire periph-ery of the cornea, which normally increase with advanced age. A lipid-free clear zone along the limbus will be discernible. Patients younger than 50 years who develop arcus senilis should be examined to exclude hyper-cholesteremia as a cause. Arcus senilis requires no treatment as it does not cause any visual impairments.
The deposits and pigmentations discussed in the following section do not generally impair vision.
Bilateral gray or brownish epithelial deposits that extend in a swirling pattern from a point inferior to the pupil. This corneal change typically occurs with the use of certain medications, most frequently with chloroquine and amiodarone. Fabry’s disease (glycolipid lipidosis) can also exhibit these kinds of corneal changes, which can help to confirm the diagnosis.
Topical medications containing silver and habitual exposure to silver in elec-troplating occupations lead to silver deposits in the conjunctiva and the deeplayers of the cornea (argyrosis). Systemic gold therapy (more than 1 – 2 g) willlead to gold coloration of the peripheral corneal stroma (chrysiasis).
Any irregularity in the surface of the cornea causes the eyelid to distribute the tear film irregularly over the surface of the cornea; a small puddle of tear fluid will be present at the site of the irregularity. Iron deposits form in a charac-teristic manner at this site in the corneal epithelium. The most frequently observed iron lines are the physiologic iron deposits at the site where the eyelids close (the Hudson-Stähli line), Stocker-Busacca line with pterygium, Ferry’s line with a filtering bleb after glaucoma surgery, and Fleischer ring with keratoconus. Iron lines have also been described following surgery (radial keratotomy; photorefractive keratectomy; keratoplasty) and in thepresence of corneal scars.
This golden brown to yellowish green corneal ring is caused by copper deposits at the level of Descemet’s membrane in Wilson’s disease (liver and lens degeneration with decreased serum levels of ceruloplasmin). This ring is so characteristic that the ophthalmologist often is the first to diagnose this rare clinical syndrome.