Diabetes and diabetic retinopathy: Q&A
How Does Diabetes Affect Eyes?
Q: How does diabetes affect your eyes? — L.L., Connecticut
A: Diabetes causes problems in the retina with what are collectively called microvascular abnormalities. The small blood vessels develop microaneurysms and leak blood. New blood vessel growth (neovascularization) occurs. Unfortunately, these blood vessels are weak and also leak. These leaks (hemorrhages) can cause irreversible damage to the retina and permanent vision loss.
Patients with controlled diabetes do better than those with uncontrolled diabetes. However, even a person whose diabetes is under perfect control can still develop diabetic retinopathy — hence, the need for yearly retinal exams. — Dr. Slonim
Q: Does diabetic retinopathy get progressively worse? — F.R.
A: Yes. When left unrecognized and untreated, diabetic retinopathy can get worse and eventually lead to blindness. Diabetic retinopathy can even get worse despite use of the best treatments that currently exist for it. — Dr. Slonim
Q: My father has type 2 diabetes and he is seeing double. We went to the hospital about a week ago and they said the diabetes had affected a nerve to his right eye. Can medicine get his sight back to normal? — W.C.
A: Diabetes can affect any one of the three cranial nerves (nerves that emerge directly from the brain) that are responsible for movement of the eyes. Diabetes is one of the more common conditions associated with paralysis (palsy) of the sixth cranial nerve. Paralysis of this nerve affects the lateral rectus muscle that allows the eye to look outward. There is no specific medicine for this. The paralysis can be temporary and last a few months or it can be permanent. — Dr. Slonim
Q: Can diabetes cause you to have eye infections such as pink eye and frequent styes? — K.M.
A: That's a great question! Yes, people with diabetes are more likely to get bacterial infections, including bacterial pink eye and/or eyelid styes. Diabetes affects the autoimmune system, lowering one's resistance to infection. Keeping your A1c (marker of blood sugar levels) as low as possible and practicing good hygiene such as washing your hands frequently and avoiding touching or rubbing your eyes can help. — Dr. Dubow
SEE ALSO: How to get rid of a stye
Diabetic retinopathy symptoms
Q: I'm 54 and have type 2 diabetes. About two weeks ago I got vertigo, which is when it seemed like my vision changed. My general practitioner sent me to see my eye doctor, who told me I would need to wear eyeglasses all the time and not just for reading and the computer.
My eye doctor said that having my diabetes under control brought on the change in vision. He said that, while numbers are high, this swells the eye. But once blood sugars are stable, the eye goes back to normal.
Is this true or do I need to see another eye doctor? It just seems backwards that if your blood sugar readings are good, your eyes get worse. Hope you can help me. — E.
A: Fluctuating blood sugars are known to cause fluctuating vision. There is a correlation between the change in blood sugar levels and the ability of the crystalline lens in your eye to maintain a sharp focus.
Your eye doctor is correct that vision cannot be corrected until your blood sugars remain stable.
Eye doctors typically will not prescribe a pair of glasses for a diabetic whose sugars are not under control. Your vision during periods when your blood sugar was out of control may have coincidentally been in the normal range.
Once your blood sugars changed or normalized, then your vision changed. Unfortunately, it changed for the worse. — Dr. Slonim
Q: Can a person have diabetic retinopathy without having any noticeable visual difficulties? — V.S.
A: Absolutely. Small leaks in the retina can happen to any person with diabetes, even someone doing a great job of managing sugar levels. These leaks can be in areas of the retina that don't cause any vision symptoms whatsoever. That's why it's super important to have regular, dilated eye examinations. Leaky vessels, if serious enough, can be treated to prevent major vision loss. — Dr. Dubow
Q: My dad is diabetic and for the first time today he experienced a sort of sight loss in his right eye. He said he saw shadows and felt like a little white thread was on his eye. He could see a blood spot right in front of his eye. What does that mean? Is he losing his eyesight from being diabetic? — I.
A: Any type of vision loss in a diabetic or non-diabetic needs to be thoroughly checked out by a qualified eye doctor. Not only can diabetes cause vision loss but so can vascular problems in the eye, which are similar to a stroke in the brain. — Dr. Slonim
Q: I was recently diagnosed with diabetes. I have been nearsighted for 25 years. After I started taking medication, my vision improved to a point where I no longer needed glasses for distance, but my near vision got worse.
Now I am starting to reverse, and I am again starting to use my glasses again (the prescription is not right). Is this typical of the disease? Will my eyesight level out? If so, how long should I wait to get new glasses? — M.H., California
A: As blood sugars go up or down in diabetes, vision can change. If the sugar level changes are minimal, so are the vision changes.
A good rule of thumb for knowing when to get new glasses is to watch your A1c readings (average of three months glucose levels). If you are relatively stable, your glasses prescription will be accurate — especially if your A1c readings remain at or below 7 percent.
You may want to discuss this with the physician managing your diabetes and your eye doctor. They can help interpret your results. — Dr. Dubow
Q: I've been having some cloudy vision and wonder if I should see the eye doctor first or physician first to check for possible diabetes. My maternal grandfather has type 2 diabetes. I also have taken Mestinon in the past for myasthenia gravis, but it seemed to be in remission, so I have not taken it regularly for while. I think maybe computer use is a factor. — D.B., Ohio
A: Chances are that your medical doctor will eventually send you to the eye doctor. I recommend that you see your eye doctor first, since it sounds like your only symptom right now is vision-related.
Problems with myasthenia gravis (a chronic autoimmune and neuromuscular disease) tend to cause double vision or drooping lids (these are the most common symptoms). Your medical doctor can check for diabetes with a blood sugar determination. — Dr. Slonim
Q: I'm almost 30 and I am in decent shape. I eat healthy and work out, but I recently was diagnosed with type 2 diabetes. Now I have noticed changes in my vision, sometimes varying by day or by week.
I currently use light reading glasses while on my computer. I have noticed blurriness at different light levels and distances. What bothers me is that one day I may see fine, and the next day I don't. Can diabetes cause this?
My eye doctor said he couldn't do anything for me until after I control my blood sugar level and keep it at a specific level for extended periods of time. Why do blood sugar levels affect the eyes and vision this way? Thank you in advance for your input and advice! — N.
A: Fluctuating blood sugars and fluctuating vision are connected, because there is a correlation between the change in blood sugar levels and the ability of the crystalline lens in your eye to maintain a sharp focus. Your eye doctor will be unable to adequately correct your vision until your blood sugars remain stable. Eye doctors typically will not prescribe a pair of glasses for a diabetic whose sugars are not under control. — Dr. Slonim
Diabetic retinopathy treatments
Q: I am diabetic and experiencing problems with my vision, such as blurriness. Can this be reversed through medication, proper diet or anything else? In other words, are these eye problems permanent in all instances? — C., South Africa
A: There are a number of possible reasons for blurry vision. The simplest is the possible need for a pair of prescription glasses. More complex reasons include cataracts that can be removed, macular degeneration for which there are treatments and diabetic retinopathy that can be controlled when identified.
It sounds like you need a complete eye examination by a qualified eye doctor to determine the source of your blurred vision. Possible treatments will be determined once the origin of your blurriness is identified. Good luck. — Dr. Slonim
Q: Recently my sister was diagnosed with borderline diabetes. However, during a recent eye exam it was discovered she has leaks in both of her eyes. We will be going to an eye specialist, but I am afraid for my sister. Her doctor is controlling her diabetes with diet and exercise. But I know leaks in the eyes are very dangerous. How successful is the laser surgery for these types of leaks? — J.R.
A: Laser treatments for diabetic retinopathy are very successful but the success rate depends on the size and the location of the leak, the length of time that the leak has existed and the stability of the diabetes. — Dr. Slonim
Contact lenses and diabetes
Q: Are diabetics able to use contacts? — J.H.
A: Yes, most people with diabetes can wear contact lenses. They must be properly prescribed and managed to make sure the wearer's eyes stay safe and healthy. This means using the correct lenses, the correct care system and having regular visits with the doctor to monitor eye health and vision. — Dr. Dubow
Diabetes and eye exams
Q: I have type 2 diabetes that is under control (daily sugar count is very seldom over 110 first thing in the morning). Is it still necessary to have the dilated eye exam annually? — M.G.
A: Yes! Your eye doctor is an important part of a medical team managing your diabetes.
Damage from diabetes usually shows up first in what are called the "end organs" of the body, meaning the fingers, toes, kidneys and eyes. They can suffer the most from a lack of oxygen caused by too much sugar in the blood.
And damage can happen even with tight glucose control. Retinal damage, particularly leaky blood vessels in the retina, can be treated to avoid major vision loss.
The eyes are the only body organs that have windows (the pupils) to see inside and find out what's going on. A dilated eye exam can help pick up minor changes that can help your doctors know if your diabetes is stable or not. It's truly a peek inside your body — a small price to pay for good health! — Dr. Dubow
Q: I have diabetes. How often should I be checked to make sure my eyes are okay? — E.B., Pennsylvania
A: Diabetes is the number one cause of blindness in the United States. Although diabetics have elevated blood sugar levels, the real damage is done by lack of oxygen. Because the eyes have such tiny blood vessels and yet need a lot of blood (and therefore oxygen), diabetes can cause a great deal of damage.
Diabetes also can cause leaking of blood vessels in the eyes, which leads to scarring and loss of vision.
It is extremely important for diabetic patients to see their eye doctor at least once a year to have their pupils dilated and a thorough retinal exam performed. If blood leaks are found, an eye surgeon can seal the leaking vessels with a laser. There also is a technique that uses a laser to destroy "unnecessary" retinal areas to provide more oxygen to the important areas.
Most eye doctors — optometrists and ophthalmologists alike — recommend annual eye exams for people with diabetes, though in some cases more frequent exams are advised. — Dr. Dubow
Q: How does age affect vision? I've noticed as I grow older my sight is getting worse. How often should a person get an eye exam? — C.D., Louisiana
A: Being over 50, I can attest to the fact that the eyes do change with age! They actually change in a number of ways. The most obvious change usually happens between the ages of 40 and 50 when we lose our ability to focus on near objects and small print. This is called presbyopia, and it happens to all of us at some time. Progressive eyeglass lenses certainly are a wonderful invention to those of us in this category!
There are other changes as well:
The liquid that fills the back of the eye (vitreous) changes in color and density, causing our vision to dim and colors to appear less bright.
Our tears change, causing many of us to have problems.
The skin around the eyes loosens, causing some eyelid droopiness.
The pupils get smaller and don't react as fast, making it more difficult to see clearly in dim light and adjust to lighting changes.
Sounds grim, huh? Well, in truth, most people do just fine with these changes. The important thing is to have your eyes checked yearly to watch for diseases that can cause real problems with your vision (and your health), such as diabetes, high blood pressure, macular degeneration and glaucoma. — Dr. Dubow
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Page updated September 2020