What happens to vision during normal aging?
Normal Aging and Vision
- Floaters – Strands of protein in vitreous
- Dry Eye – Poor quality of tears or insufficient tears produced by the lacrimal glands
- Increased need for light – An 80-year-old will need 10 times more light as compared to an average 23-year-old
- Increased susceptibility to glare
- Reduced dark/light adaptation
- Reduced contrast sensitivity – A 75-year-old needs 2 times more contrast, and a 90-year-old will need 6 times more contrast
A study by the Smith-Kettlewell Institute, called the SKI Study, focused on vision function for performance in ADLs and IADLs. There were a few conditions that they identified.
Presbyopia. It is an age-related accommodative decline in amplitude. It means when we, as individuals, hit the age of 40 and above, and I am right there, we will need glasses to read.
Floaters. These are stands of protein in the vitreous. These may look like cobwebs or worms when looking at the sky. It reflects those proteins onto the retina because the vitreous is not as dense, as the vitreous gets more fluid-like as one gets older.
Dry eye. Dry eye is not a serious medical condition but can be very debilitating. There is poor quality or insufficient tears produced by the lacrimal glands. If the client tells me they have dry eyes or if I read this diagnosis in the medical chart, I immediately jump to the 20/20/20 rule. For every 20 minutes of sustained near vision with tasks like looking at a screen (which has been our life during the pandemic), the individual needs to look 20 feet away for 20 seconds and blink. Blinking stimulates the lacrimal glands to secrete tears.
Increased need for light. There is a high need for light as we age. And that is because the pupil diameter gets smaller and smaller as we age—an 80-year-old needs 10 times more light compared to an average 23-year-old. There is also increased susceptibility to glare because the cornea and the lens are losing their smoothness.
Reduced dark/light adaptation. There is diminished dark-light adaptation because the neural impulse is generated when light strikes the photochemicals in the photoreceptors, which must be reinstituted. When there is a delay, we have reduced dark and light adaptation. Again, if you walk into a dark theater, it takes you a few minutes to get accommodated, and vice versa when going into the light. This adjustment gets longer over time with reduced dark/light adaptation.
Reduced contrast sensitivity function. A 75-year-old needs two times more contrast, and a 90-year-old needs six times more contrast.