The most common problem with the crystalline lens is development of a cataract. The second most common problem is lens luxation. Luxation means to move out of normal position. The lens is held in place by thousands of tiny zonular fibers that hold the lens in its normal position at the periphery or equatorial portion of the lens. These fibers are not normally observed. Variation in tension on these fibers is what occurs when the eye focuses for near vision verses far vision. This is a much greater factor in human beings than with our pets where that function is less developed. This may be because our pets do not have a fovea or macula for the acute vision of their human counterparts for reading, etc. Lens luxation occurs either as an inherited condition often seen in terrier breeds or secondary to other disease processes. The lens can luxate in advanced glaucoma where the eye physically enlarges or from inflammatory processes such as uveitis, of which there are many causes. The lens will either luxate forward, termed an anterior luxation, or backwards, termed a posterior lens luxation. In general, a posterior lens luxation is a more benign process and will often fall back into the lower portions of the posteriorly located vitreous. This may allow for some return of vision. When the lens luxates forward into the anterior chamber it can be a much more significant problem. Anterior lens luxation can block the flow of aqueous humor through the pupil stimulating a secondary glaucoma, termed pupillary block glaucoma. Also, the lens can bump up against the cornea and significantly damage the cells on the inside of the cornea (endothelial cells), causing significant damage. In general, if a lens luxates anteriorly, surgical removal of the lens is recommended to prevent the above problems. The anterior lens luxation can be readily removed with an intracapsular extraction. This means the lens material stays within its outer membrane or lenticular bag. The lens is removed in one piece and is a very successful procedure. With removal of the lens totally, you now have a clear visual access and in many cases, a very reasonable and visual eye, even without a lens being present.