Eyes:  illuminating the aging process

Aging causes a gradual decrease in gastrointestinal nutrient absorption, so supplementation with antioxidants important for ocular health is essential for healthy eyes.

While aging is a natural part of life, genetic and environmental factors dictate the aging process and the eyes reflect how well we (and our animal patients) age. Nowhere is this truer than in the lens, which contains cells from every stage of our lives, including even embryonic and fetal cells within the nucleus. The living lens literally encapsulates the aging process, making our eyes the window through which to observe the body’s health. Eyes are exposed to constant oxidative stress from sunlight, allergens, pollution and diet. Every individual ages a little differently and at different rates depending on his or her overall health and genetics. Vision declines gradually with age in some patients, and faster in others.

Cataract” is a term commonly used to describe cloudy eyes, but many abnormalities can cause your patients’ eyes to look opaque. From external (cornea) to internal (lens and vitreous) structures, any of these normally clear tissues can appear cloudy with natural aging.

The aging cornea can accumulate lipid or cholesterol deposits, which are exacerbated if high serum cholesterol and/or triglyceride levels are present. Older dogs commonly develop non-healing (“indolent”) superficial corneal ulcers (erosions). Aberrant calcium deposits can occur, which may trigger corneal ulceration in aged animals; severely affected dogs are usually older and have very deep ulcers or even perforated corneas. Sadly, sometimes enucleation or euthanasia is needed because therapy is not effective or even possible.

Nuclear sclerosis is a hardening of the aging lens nucleus and manifests as a bluish hazy appearance. This does not typically interfere with sight. Cataract formation increases with age. Though older dogs are commonly presented for cataract evaluation, they often have nuclear sclerosis and not cataracts. Elderly dogs have senile retinal degeneration due to rod photoreceptor loss, which causes poor vision in dim light, especially at night.

The vitreous can develop opacities with age through liquefaction (“syneresis”) or by forming multiple “floaters” (“asteroid hyalosis”).

Natural aging in all cells is hypothesized to occur through a variety of pathways, including damage to cell membranes, shortening of telomeres, accumulation of oxidative stress, mitochondrial decline, excessive physiologic stress resulting in damage to the hypothalamus, and many others.

Natural dietary antioxidants protect mitochondria and cell membranes and slow telomere shortening.

  • Grapeseed extract is a potent free radical scavenger that protects lens cells from UV damage.
  • Lutein, zeaxanthin and astaxanthin carotenoids protect against lipid peroxidation, accumulating in the cornea, lens and retina; and act as blue light filters in the retina.
  • Omega 3 fatty acids protect the retina against oxidative stressors, including light and aging.
  • Vitamins C and E protect the retina against blue light damage. Vitamin C is present in the lens and aqueous humor, while vitamin E is highly concentrated in the retina.
  • Alpha lipoic acid potentiates vitamin C and E levels and increases the body’s production of glutathione.
  • Coenzyme Q10 protects against lipid peroxidation, which decreases with aging.

Aging causes a gradual decrease in gastrointestinal nutrient absorption, so as our patients age, daily dietary supplementation with antioxidants that are important for ocular health is an essential strategy for healthy eyes.