The Truth Behind Grey Eyes In Aged Dogs

As your dog gets older, you usually tend to notice visible symptoms of their aging such as loss of hair, slower movements, weight changes etc. But one common characteristic that we clearly notice is that relating to their eyes, that turn into a bluish-grey colour. Most people may just assume that it is a cataract, as it commonly appears in humans as they age too. However, this is a misconception.

Cataracts focal and diffuse opacities in the eye that are caused due to changes to the nature of crystalline proteins in the lens. These proteins tend to ‘clump up’ together, eventually forming a cloudy opacity. The lens changes from its usual, transparent nature to an opaque one. The reason behind this is due to a variety of factors including traumatic, congenital, metabolic issues and pathophysiological mechanisms that result in obstructions to visual pathways and lead to succeeding vision deficits. These can occur in dogs at any age and are often common in specific dog breeds. For example, Siberian Huskies, American Cocker spaniels and Boston Terriers are genetically predisposed to cataracts. These can lead to serious blindness once the cataract matures, followed by other complications such as secondary glaucoma, lens dislocation and chronic intraocular inflammation (uveitis).

While the chances of developing cataracts might actually be more in dogs suffering from ocular inflammation or metabolic diseases such as diabetes, not every cloudy eye indicates the presence of a cataract. It is more likely that your dog has developed a condition called Nuclear Sclerosis or Lenticular Sclerosis. This develops in their lens as its fibres become degenerative over time and start to compress. The lens’s nuclear density increases as well leading to its translucency, reducing the sharpness of vision. However, as in the case of cataracts, it does not lead to complete blindness. The bluish grey haze only mildly impairs vision, still allowing them to see their surroundings normally. While cataracts have multiple different stages of progression and can either form slowly or rapidly, lenticular sclerosis tends to develop slowly over time as the dog itself ages. The image clearly indicates that lenticular sclerosis (A) can easily be differentiated from cataracts due to their distinct clinical features and characteristics.

Subsequently, the prognosis to treat these conditions would evidently differ as well. While lenticular sclerosis does not really require any treatment unless it causes extreme discomfort, having a cataract may require the dog to undergo surgery, called phacoemulsification, involving the removal of the cataract. In other cases, a topical treatment with anti-inflammatory drops can be provided to prevent any cataract related ocular disease.

Hence, make sure that your dog undergoes routine checks and periodic ophthalmic examinations. Veterinarians tend to test their tapetal reflex, eye functionality and appearance via slit lamp biomicroscopies and an ophthalmoscopy. If there appears to be any cloudy formation in their eyes, make sure to consult a professional before you arrive at any conclusions, as appearances can often be misleading.

Bibliography:

1. https://www.petmd.com/dog/conditions/eye/c_dg_cataract
2. https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-topics/canine-cataracts
3. https://www.voreyevet.com.au/uncategorised/nuclear-sclerosis-or-cataracts-which-is-it/
4. https://todaysveterinarynurse.com/wp-content/uploads/sites/3/2020/05/Grogan_Cataracts_TVNSummer2020.pdf
5. https://assets.ctfassets.net/4dmg3l1sxd6g/48cUiOTGRg7jnEJhp8cA8/33c5a39f6a3a80f6f90a043bde03d838/prop_differentiating-nuclear-sclerosis-from-cataracts-26796-article.pdf
6. https://pubmed.ncbi.nlm.nih.gov/15762923/