People who visit an optometrist may complain that they feel like they're looking through a window that's frosty or fogged up. They may also be having trouble driving at night due to glare, difficulty reading or seeing the expression on another person's face. Some already suspect they have cataracts, and that is a scary prospect to those who are diligent about monitoring their health and are highly active. Boulder, Colorado residents are among some of the largest population in this category. But...what if those that were suffering from these symptoms had the inability to describe their symptoms to someone else? That is the problem that dogs face and the reason why their owners need to be paying attention for them!
Yes, Dogs Develop Cataracts Too
Like humans, the lenses in dogs' eyes undergo changes as they age. Lens tissue breaks down and clumps together, clouding small areas inside the lens. This is known as a cataract, and it scatters any light passing through the lens, preventing sharply-defined images from reaching the retina, which results in blurred vision. Compile that with normal age-related loss of lens elasticity and transparency, and the cloudiness of the lens intensifies, compromising his vision further. Unfortunately, often by the time an owner notices this issue, their dog has a mature cataract that is in need of immediate attention.
Why Immediate Veterinary Care?
Dogs with lenses that are clouded by 30% may display no symptoms; however, by the time the lens has 60% opacity the owner may notice he has trouble seeing when the light is dim or he may show signs of hesitation when climbing the stairs. The sooner the owner notices a cataract the better. If left untreated, the cataract can slip within the lens and float around the eye. If it settles in a spot where it blocks fluid from draining naturally, the fluid builds up and leads to glaucoma, which can result in total blindness. In dogs, mature cataracts can also deteriorate over time and break up, inflaming the eye and causing the dog extreme pain.
Arriving at a Diagnosis
The veterinarian will do a blood workup, biochemistry profile panel and urinalysis, which while nonspecific as it applies to the actual cataract, will determine if the dog has diabetes or hypocalcemia. These are conditions that can lead to cataracts. The vet will also review the dog's medical history, question the owner as to the nature and onset of the symptoms and perform a complete physical examination, putting focus and concentration on the ocular region. If the owner is able and willing, the dog may be referred to a specialist who will use ultrasound or a procedure that measures the electrical response of the retina's cells. This is called electroretinography. These advanced diagnostics can help to confirm whether or not cataract surgery is indicated.
Virtually all dogs develop a condition called nuclear sclerosis after they reach the age of six. This is a hardening of the lens that causes it to appear blue or gray. Nuclear sclerosis does not cause blindness and requires no treatment. In fact, it also occurs in most humans once they reach their 40's. This hardening of the lens and loss of elasticity is not accompanied by cloudiness in humans but does compromise near vision and can result in the need for reading glasses. Dogs do not have near vision acuity to begin with, so they don't experience a decline. So while a human and his dog may both chose cataract surgery at some point, only humans get to benefit from the use of glasses!