Asteroid hyalosis is a degenerative condition of the eye involving small white opacities in the vitreous humor. It is known to occur in humans, dogs, cats, horses, and chinchillas. Clinically, these opacities are quite refractile, giving the appearance of stars (or asteroids) shining in the night sky—except that ocular asteroids are often quite mobile. Ocular asteroids must be distinguished from the more common typical vitreous floaters, which are usually fibrillar or cellular condensates. The cause of asteroid hyalosis is unknown, but it has been associated with diabetes mellitus, hypertension, hypercholesterolemia, and, in certain animals, tumors of the ciliary body. In dogs, asteroid hyalosis is considered to be an age related change. The asteroid bodies are made up of hydroxylapatite, which in turn consists of calcium and phosphates or phospholipids. While asteroid hyalosis does not usually severely affect vision, the floating opacities can be quite annoying, and may interfere significantly with visualization and testing of the retina. While treatment of asteroid hyalosis is usually unnecessary, vitrectomy may occasionally be indicated, for both diagnostic and therapeutic purposes. See also
Synchysis scintillans

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They are notorious for their negative impact on the corneal endothelial lining, which is vital for maintaining a healthy clear cornea. Iris-fixated PIOLs, attached by claws to the mid-peripheral iris by a technique called enclavation. It is believed to have a lesser effect on corneal endothelium. The main complication with this type is their tendency to cause endothelial cell reduction. Sulcus-supported PIOLs, placed in the posterior chamber in front of the natural crystalline lens. This type of PIOLs is gaining more and more popularity. They have special vaulting so as not to be in contact with the normal lens. The main complication with older versions was a small possibility of cataract formation. Blue-light filtering IOLs
Blue light filtering IOLs filter the UV and high-energy blue light present in natural and artificial light, both of which can cause vision problems; however too much filtering of blue light can increase depression, especially in the winter months (SAD). The trademarked "Natural Yellow" material is available in three hydrophilic IOLs. Dr. Patrick H. Benz of Benz Research and Development created the first IOL material to incorporate the same UV-A blocking and violet light filtering chromophore thats present in the human crystalline lens in order to attempt to protect the retina after cataract extraction of the natural crystalline lens. A Cochrane Review found little evidence of important differences between blue‐light filtering and non‐blue‐light filtering lenses for protecting the macula (back of the eye) after cataract surgery. This was due to studies being too small and too short‐term to provide reliable results.