As we all know, there are many eye conditions caused by diabetes.
When we examine and discuss changes and findings with our diabetic patients, while it is not our intention, we can overwhelm them with too much information. Medical jargon is not something you want to be using with patients. We have all seen the way patients misspell medications, allergies, and history on intake forms like “Atendolol,” “Lexsapro,” “immaculate degeneration,” and worse!
Patient education is one of the keys to management and compliance for diabetes. My goal is to educate patients in such a way that they can repeat and explain findings to their family and friends when they go home. This helps with compliance and referrals—it’s a win-win. So here are a handful of analogies I use to explain some of the many eye conditions caused by diabetes to my patients.
1) Myopic Shift and or Diabetic Cataract
Increased glucose levels in the body leads to increased glucose levels in our eyes. This in turns causes the glucose to “force” its way into the lens. The glucose that gets processed inside the lens causes a hyper-osmotic environment, which leads to water diffusion into the lens. Gradient diffusion causes the lens swells up like a balloon, causing a change in refractive state/vision.
So how do we explain this to patients? Compare this to a mirror!
Think of it this way…
The lens in our eyes is like a Ziploc bag of clear water. There are pumps on the surface of bag that pump water and nutrients in and out. When there’s an increased level of glucose or sugar in the body, it causes the lens to swell up like a balloon. At this point, patients can experience a change in their vision. If left untreated, this constant high stress situation can cause changes in lens fibers leading to a cataract. And that cataract—well, now imagine that your Ziploc bag of clear water has become a bag of ice tea, and think about how much more difficult it is to see through it!
Image Source: Dr. Mark Deist
Here are 46 clinical analogies sourced by many of the writers and contributors on NewGradOptometry.com!
2) Pericyte Drop-Out
Pericytes are cells that wrap around the blood vessels ensuring proper stability and control of what goes in and out of the lining. Too much sugar in the bloodstream causes these pericytes to “drop out,” thus compromising the blood vessel lining. The exact mechanism is unknown, but it can be certain that hyperglycemia causes pericytes to drop out.
How on earth do you explain this one to patients!?
Think of it this way…
There are these things called pericytes, which are groups of cells that you can imagine hold down the fort, ensuring a strong barricade between the inside and outside of every blood vessel. When you are overloaded with too much sugar, these pericytes get “poisoned,” and start to drop out and can’t maintain the barricade. Just like the walls of a fort, the blood vessel lining starts to lose its protection and reinforcement, and will start to bulge out like a balloon (microaneurysms). This bulged out portion of the blood vessel is now thinner, weaker, and more susceptible to allowing fluid to leak out (dot/blot hemes).
Image Source: Handbook of Diabetes, 4th Ed., Excerpt #14: Diabetic Eye Disease
3) Subretinal Fluid Leakage
Now we have weakened and leaky blood vessels. As we know, this leakage and fluid builds up within retinal layers, specifically in the inner plexiform layer (IPL) and outer plexiform layer (OPL). As the leakage continues, the layers become thicker and thicker which in turn hinders light transmittance to photoreceptor cells.
So where does this leave us with our patient?
Think of it this way…
The leaking in the retina can be compared to an irrigation system of the lawn on a golf course. The hoses and pipes (blood vessels) provide water to certain parts of the lawn (retina) in a controlled manner. As the hoses and pipes degrade and become leaky, it causes unwanted concentrated puddles in certain areas. This then leads to parts of the lawn to swell up due to increase fluid in the soil. During the early stage of the leaking, the lawn can appear “normal” just like the retina, but if left untreated, the lawn’s root system can weaken thus causing bare spots, or in terms of the eyes, vision disruption. At this point, damage has been done, and fixing things can be extremely challenging.
There’s a “sweet spot” in the back of the eye called the macula. It is what we use to see straight ahead, like when you read letters on the chart. This can be compared to the hole on the golf course. As fluid leaks, it changes the landscape of the retina and can cause fluid to build up in that sweet spot. Just like it would be almost impossible to put a golf ball in a hole overflowing with water, it becomes really hard to see when the macula is filled with fluid.