Age-related loss of kidney function ( glomerulosclerosis ) is the most common cause of a hign BUN in pets. I see as much of this kidney disease in shelter dogs and cats as in pampered pets. Over the years, veterinarians have suggested that antigen/antibody accumulation ( immune complexes ), amyloidosis , high protein diets or even leptospirosis ( specific ref ) might be the root cause of kidney decline over time. While that may be occasionally true, no one is entirely convinced that your pet's lifestyle and disease exposure account for the great majority of failing kidneys that veterinarians see. Its not much different in us humans. ( ref)
A retinal detachment occurs when the retina is pulled away from its normal position in the back of the eye. The retina sends visual images to the brain through the optic nerve . When detachment occurs, vision is blurred. A detached retina is a very serious problem that almost always causes blindness unless it is can be from tears or holes in the retina, or from fluid accumulation between the retina and underlying layers. When there is a tear of the retina, liquid from the vitreous may pass through the tear, and detach the retina. As the fluid accumulates, the retinal detachment becomes larger. Detached areas of the retina lose their vision. Most people notice floaters and flashes before the retina detaches. As the detachment occurs, a gradually enlarging dark area may be seen. Anyone with flashes or the sudden onset of a new floater (or floaters) should be examined promptly by an ophthalmologist . The ophthalmologist will search carefully for retinal tears.