What is the difference between nuclear sclerosis and cataracts

For prognostic purposes, the latter is perhaps the most critical distinction. Incipient cataracts are early opacities that involve less than 10 to 15 percent of the eye and do not affect vision.

Immature cataracts are opacities that are more marked but still incomplete. The lens begins to swell, sight is often affected, and the fundus may be partially obscured ophthalmoscopically. Mature cataracts often produce complete lens opacity, clefts and intumescence lens swelling.

In the hypermature stage, degradative enzymes are released from degenerative and ruptured lens fibers, and cause further proteolysis within the lens. The lens capsule begins to shrink and the anterior chamber deepens. Liquefaction and resorption of the cataract may result in areas of the tapetal reflection becoming visible.

As hypermature cataracts advance, the lens nucleus may sink ventrally, resulting in a "Morgagnian" cataract. It is impossible to accurately forecast the rate of cataract progression.

Acquired cataracts may mature over months to years, while diabetic cataracts seemingly develop overnight and may mature in a matter of weeks. Some affected animals undergo lens capsule leakage and cataract resorption. Others have cataracts that, once mature, remain stable indefinitely.

Nuclear sclerosis does not significantly impair vision. But cataracts — the most common cause of blindness in dogs — can, depending on their size and stage. While cataracts that are adequately large or axial to obstruct the passage of light to the retina, the degree of vision loss is variable, and it can be difficult to correlate with ophthalmic findings. Cataracts can also predispose the animal to other serious eye problems. The chief sequela to hypermature cataract is lens-induced uveitis, which results from the leakage of antigenic material from the lens into the anterior chamber.

Anterior uveitis causes blepharospasm, conjunctival hyperemia, miosis, aqueous flare, ciliary spasm and hypotony. If left untreated, chronic uveitis can lead to glaucoma, retinal detachment and permanent blindness. Cataract surgery is indicated whenever lens-induced uveitis is present. Ophthalmologist Carmen Colitz also recommends surgery when cataracts are in the mid- to late-immature stage, are progressing rapidly, or when vision loss seems to have exceeded 40 percent.

Surgery performed early has improved the success rate of more than 95 percent, she estimates. Surgery done in the hypermature stage carries an to percent success rate, due to increased risk of developing glaucoma and retinal detachment postoperatively. Prior to recommending surgery, electroretinography ERG should be performed to assess retinal function.

Uveitis and any underlying medical conditions, such as diabetes mellitus, should be stabilized before surgery. And when cataracts are the result of a patent hyaloid artery, surgery in young animals should be postponed until these embryonal structures regress. The surgical procedure, phacoemulsification, involves ultrasonic destruction of the lens.

The softened lens material is then aspirated from the capsule. An intra-ocular lens is implanted within the empty capsule, restoring refractive and focusing ability. In rare cases, such as lens luxation, removal of the lens capsule is also indicated. Some ophthalmologists suture in an intraocular lens. Postoperative medications should be administered to reduce the risk of complications like infection, inflammation, bleeding and scarring. In some cases in which cataract surgery is not indicated or not an option, topical mydriatics can be used to improve vision.

As for the question of when to refer a patient with cataracts to an ophthalmologist, Colitz recommends: "Refer them to a specialist as soon as you first notice a cataract because you can't predict how quickly it will progress. However, it is important to visit your veterinarian if your pet has cloudy eyes so more serious conditions such as cataracts and glaucoma can be ruled out.

As an animal ages, fibers on the outer edge of the lens compress the inner lens causing it to harden and become opaque. This aging change of the lens in known as nuclear sclerosis. The most common symptom of nuclear sclerosis is cloudiness and bluish discoloration in the eye. Although both eyes are usually affected, pets with the condition rarely experience severe loss of vision.

Although the symptoms of cataracts and nuclear sclerosis may be similar, they can impact your pet in very different ways. Articles Search our articles or browse by category below. Browse Our Library. Cataracts vs. What Are Cataracts?

Near vision is used for tasks like reading, working on a computer, or knitting. This can easily be corrected with a pair of reading glasses with the proper prescription to correct for the effect of the lens hardening. In contrast, nuclear cataracts affect distance vision more than near vision. One effect of cataracts is that they can make driving more difficult.

If you have nuclear cataracts, you may have the following symptoms:. The material that forms the lens of the eye is composed of proteins and water.

The fibers of lens material are arranged in a very orderly pattern, which allows light to pass through. As we age, new fibers form around the edges of the lens. This pushes the older lens material toward the center of the lens, causing the center to be denser and cloudier.

The lens may also take on a yellowish color. The proteins in the lens start to clump, scattering light instead of allowing it to pass through. Cataracts cause about half of all blindness in the world, and nuclear cataracts are the most common type.

Cataracts can be a normal part of aging, but they can also occur earlier due to exposure to UV light, smoking , and steroid use. Diabetes is also a risk factor for cataracts. An eye doctor, ophthalmologist, or optometrist can check for nuclear sclerosis and cataracts by examining the eye carefully. Clouding and yellowing of the nucleus may be identified during a routine eye exam. If the hardening and cloudiness turns into nuclear cataracts, your vision and condition will slowly worsen over time.

But it may be years before you need to have the lenses replaced. Serious complications of cataract surgery are uncommon. If complications do occur, they can lead to vision loss. Complications may include:. In some people, the pocket of tissue in the eye that holds the new lens in place posterior capsule can become cloudy and impair your vision again following cataract surgery.

Your doctor can correct this by using a laser to remove the cloudiness. This allows light to travel through the new lens unimpeded. The lens hardening can impair near vision, but this can be corrected with reading glasses. If the hardening of the lens progresses to cataracts, replacing the lenses through surgery is generally safe and reverses vision loss. If you notice changes in your vision, especially sudden changes, have an eye exam.