Cataracts affect over 15 million people worldwide and it is one of the leading causes of blindness. While no one wants cataracts, researchers want to learn more about cataracts. Their work is shedding light on the neurological benefits of cataract surgery, as well as what’s going on in the cellular level that is leading to cataracts in the first place.
Benefits of Cataract Surgery
It’s more than just being able to see better, although that is a major reason to have cataract surgery done. The Adult Changes in Thought (ACT) study done at the Seattle-based Kaiser Permanente Washington, found that those who had cataract surgery done had a 30 percent lower risk of developing dementia and this reduction continued for almost 10 years after the surgery.
While the association between cataract surgery and lessened dementia risk wasn’t determined, researchers think that persons who have the surgery are getting higher quality sensory input as a result of improved vision. This is consistent with the idea that sensory input is important for brain health.
Another reason for the reduction in dementia may have to do with people getting more blue light. There are specific cells in the retina that are associated with cognition and the regulation of the sleep cycle. These cells respond to blue light and cataracts ends up blocking blue light. So, cataract surgery may reactivate those cells, which leads to a reduced risk of dementia.
Protein Ion Channels and Cataracts
As great as it is that cataract surgery can restore vision and reduce the risk of dementia, the question remains what are the biological mechanisms that lead to the development of cataracts. Scientists at the University of Arizona College of Medicine-Tucson are studying this to in order to learn what is going on and to eventually develop nonsurgical treatments for cataracts.
Researchers, lead by Nicholas Delamere, PhD, professor and the head of the Department of Physiology, are studying the role of two protein ion channels, TRPV1 and TRPV4, play in the development of cataracts. It was his lab that discovered that TRPV1 and TRPV4 work together to regulated cell function in the cells of the eye lens.
The eye lens needs to be transparent in order for light to hit the retina and the image to be seen properly. The transparency of the lens requires a precise maintenance of ion and water content. The eye lens can’t maintain ion and water homeostasis, since it is made from tightly packed layers of cells that aren’t able to do this. That’s where protein ion channels come in, since they act as pores in the cell membrane. The protein ion channels allow for the passage of potassium, sodium and calcium in and out of the cell.
While scientist don’t understand how lens transparency is maintained, the development of cataracts is associated with the failure of biological systems controlled by TRPV1 and TRPV4.
Previous research done by Delamere’s lab showed that TRPV1 and TRPV4 in the cells on the surface of the lens act as sensors for the control mechanism that regulate water content in the lens, as well as its size, shape, optical clarity and focusing power. This study is looking at how tiny changes in hydrostatic pressure on the surface of the lens set off TRPV1 and TRPV4 to make homeostasis possible. The goal is to uncover and ultimately understand the mechanism responsible for age-related changes in the lens.
Again, research shows that there is more to a common aliment, like cataracts, than meets the eye.