When blood glucose levels are chronically elevated, damage can occur to the tiny blood vessels in the eye leading to diabetic retinopathy. The vessel wall is weakened, which allows blood and other fluid to leak out onto the retina. If this leaking is severe enough, it can cause permanent loss of vision. Sometimes swelling in an area of the eye called the macula causes diabetic macular edema. In its most advanced form, diabetic retinopathy causes new abnormal blood vessels to grow on the surface of the retina, which can lead to scarring and cell loss. In addition, fluctuation in glucose levels can cause the lens in the eye to swell. This results in the lens changing shape and can change your refractive error or glasses prescription. In other words, your glasses that worked well one day, may not work as well on another if your blood glucose levels are swinging.
The body wants blood glucose maintained in a very narrow range and insulin is one of the hormones that help regulate this. Insulin is a molecule produced by the pancreas and it is the signal for muscle, fat, and liver cells in the body to absorb glucose from the bloodstream to be used for energy. Insulin is so important in the body because we cannot survive without glucose and it acts like a key that unlocks the cells to let glucose enter them.
As mentioned above, insulin is produced by the pancreas, which allows glucose to enter the cells throughout the body. In a healthy person, this process takes place without any problems.
In type I diabetes, the pancreas in unable to produce insulin, which causes glucose to remain in the bloodstream (hence the elevated blood sugar readings) and unable to enter cells. Injecting insulin is literally lifesaving therapy to these patients.
In type II diabetes, insulin is produced and actually binds to the insulin receptor of the cell, but the cell does not get the correct signal to open the glucose channel and allow glucose to penetrate. Again, the glucose will remain in the bloodstream, unable to be used for energy production in the body and high blood sugar readings will result.
The eye is the only place in the body where we can non-invasively view blood vessels and how healthy they are. So viewing the retinal blood vessels tells us a lot about your overall health and wellness. By having an annual comprehensive checkup, diabetic complications (as well as other conditions) can be caught early and addressed. If complications are seen in the eye, chances are there could be issues in other parts of the body including, nerve damage (neuropathy), kidney damage (nephropathy), cardiovascular disease, and foot damage. As eye care providers, we are able to communicate our findings to your primary care provider, endocrinologist, and other specialists as needed allowing everyone to work together to care for you. We love being a part of your health care team!