If the surface of the eye (the cornea) is cloudy, this may be corneal edema (fluid accumulation within the cornea). Edema can be the result of a corneal ulcer, glaucoma (increased pressure within the eye), uveitis (inflammation within the eye), or chronic dry eye. These conditions are generally uncomfortable, so you may also see the dog squinting, tearing excessively, or the white part of the eye would appear unusually red. If the cloudiness involves the cornea, you should have your dog evaluated by your vet for proper diagnosis and treatment. Many of the conditions above are very serious and could result in vision loss if left untreated.
If the cloudiness is further back, in the lens of the eye, there are 2 causes:
1. Nuclear sclerosis- this is an extremely common, normal finding and is an age-related change in older dogs. Normal shedding of cells by the aging lens causes a clouding effect of the lens. It doesn't seem to affect vision much and is probably like looking through a dirty window.
2. Cataracts- cataracts can appear initially as focal areas of clouding in the lens and if they progress can involve the entire lens, giving it a solid white appearance. Mature cataracts lead to blindness. Most cataracts are inherited, predisposed breeds include: Miniature Poodles, Cocker Spaniels, Schnauzers, Golden Retrievers, and Boston Terriers. Other causes of cataracts include trauma, diabetes mellitus, uveitis, and low blood calcium levels.
The easiest way to tell the difference is if you shine a light into the eye and are still able to see through the lens enough to get a tapetal reflection (a green/ yellow glow; the tapetum is what makes a dog's eyes glow at night when a light is shined on them)with no opacity in the way, then it is nuclear sclerosis.
No treatment is required for nuclear sclerosis. If you are unable to get a tapetal reflection, I recommend you take her into your vet for a complete eye exam to determine what, if anything, should be done for cataracts. Dogs who lose vision from cataracts adjust very well to their environment in a short time. Obviously, more care must be taken that the dog doesn't wander off, and re-arranging furniture will take some adjustment on the dog's part. There is a surgery available for correction of cataracts called phacoemulsification. An incision is made in the cornea, and an instrument is inserted into the lens that breaks up and vacuums away the cataractous material. Most dogs regain some vision following the procedure, and recovery period (with some eye drops and ointments) is about a week to 10 days.
Hope this was helpful.