Diabetes and Your Eyes — More Than Retinopathy

You probably know that eye damage (retinopathy) is a major complication of diabetes. So when vision blurs, it’s normal to think the worst. But diabetes can cause blurred vision in several other ways, some of which are reversible.


I’m embarrassed to admit I only recently found out that blurred vision is a symptom of diabetes, even without any retinal damage. When blood glucose levels go up, blood gets thicker. Thicker blood pulls in more fluid from surrounding tissues, including the lenses of the eye, impacting the ability to focus.

-- Keep an eye on your vision! Learn about preventive steps and treatments for diabetic retinopathy from retinal specialist Dr. Charles Wykoff. >>

Blood sugar and blurry vision

According to WebMD, [Blurred vision] could just be a temporary problem that develops rapidly and is caused by high blood sugar levels. High blood sugar causes the lens of the eye to swell, which changes your ability to see.

Changing the shape of the lens naturally throws off vision. This can be a chronic, 24/7 kind of problem, or it can occur only after a high-carb meal, when glucose is way up. The Harvard Medical School Family Health Guide says that after-meal blurriness can be prevented by avoiding high-carb meals.

The cure for chronic, all-the-time blurriness is to get blood glucose down to normal range before meals. It may take as long three months of relatively normal blood glucose levels before vision returns to your baseline normal.

Diabetes can also cause blurriness or double vision due to hypoglycemia (low blood glucose). In this case, lens shape is probably not to blame. Low blood glucose can make it hard for the brain to focus on what the eye is seeing. Vision usually returns to normal when glucose levels rise.

If blurriness doesn’t go away when glucose levels are close to normal, you might have retinopathy. That’s a condition in which high glucose levels damage the blood vessels in the retina, or the back of the eye, which can cause blindness. Fortunately, it’s preventable and treatable.

Dilated eye exams

The American Diabetes Association (ADA) suggests that people with diabetes have regular “dilated” eye exams. Dilated means a drop will be put in the eye to open the pupil wide, so an examiner can see all of what’s inside. ADA’s guidelines include:

• An annual dilated eye exam if you are between 10 and 29 years old and have had Type 1 diabetes for at least 5 years. (Those with Type 2 are recommended to receive a dilated eye exam shortly after diagnosis.)

• An annual dilated eye exam if you are 30 or older, no matter how long you’ve had diabetes.

• A dilated eye exam if you are pregnant or planning to get pregnant.

• A dilated eye exam if you experience any changes in your vision.

Other causes of blurry vision

High blood pressure can also cause vision problems by damaging the optic nerve or through brain damage resulting from stroke. High blood pressure is very common in diabetes, so it’s important to keep blood pressure close to normal range as well.

Other eye problems can cause blurriness and blindness. These include age-related macular degeneration (AMD). In AMD, the retina gradually stops working for no clear reason, though some studies have found people with diabetes are more likely to have AMD. According to AMD.org, eating more green vegetables is one way to try to prevent AMD.

Cataracts are strongly associated with diabetes. They are a clouding of the lens in the eye that affects vision. It is thought that proteins in the eye fluid clump up for some reason and cloud the lens. Cataracts are more common in people with diabetes and in smokers. The National Eye Institute says that eating leafy green vegetable and keeping direct sun out of your eyes are good prevention measures.

Steps for eye care

In general, keeping near-normal blood glucose and eating right seem crucial to eye care. Writing in Diabetes Self-Management, Linnea Hagberg, RD, suggests “consuming leafy green vegetables like spinach, kale, collards, and broccoli.”

Hagberg also recommends corn, kiwifruit, red grapes, spinach, zucchini, yellow squash, orange peppers, orange juice, egg yolks, and Vitamin E as being good prevention for AMD and cataracts. For general diabetes eye health, she says:

• Wear sunglasses that protect the eyes from ultraviolet rays.

• Keep blood glucose under control.

• Stop smoking or cut back as much as possible.

• Choose brightly and deeply colored fruits and vegetables as often as possible. Include leafy green vegetables in your meals several times a week.

• Include plenty of vitamin C in your diet by choosing several daily servings of foods such as cantaloupe, strawberries, citrus fruits, kiwifruit, mango, papaya, broccoli, Brussels sprouts, sweet peppers, tomatoes, and cauliflower.

• Eat fatty fish two or three times a week. Limit total fat and commercially processed baked goods and snack foods.

• Have an annual eye exam (unless your doctor advises a different schedule) that includes dilating the pupils.

Have you experienced visual changes at different glucose levels? I’d be interested in hearing about it.

Want to learn more about keeping your eyes healthy with diabetes? Read “Eating for Better Vision and Healthy Eyes” and “Keeping Your Eyes Healthy” and watch “Diabetes and Your Eyes.”

Learn more about the health and medical experts who who provide you with the cutting-edge resources, tools, news, and more on Diabetes Self-Management.
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  • Joe

    Lest we forget, blurred vision that gradually appears can also be a sign that your eyewear prescription has changed, and it’s time to get new glasses/contacts.

  • Jon Hart

    Great reading on your site! I was searching for articles on the effects of anesthesia on BGLs, stumbled on this site. I’ve been elevated post some eye surgeries. I’m a grim tale fighting for my limited sight, and could pose for your diabetic eye damage poster child poster. I had yet another vitrectomy two days ago and have been doing slightly better BGL wise than my prior 10 surgery’s. He had to do another 1000+ laser points inside with a chaser of Lucentis. This is an attempt to save this eye from removal, sigh! (Yes, I use adaptive technologies to participate in this forum) Up until today then it kind of jumped up in the 240 range with a mind of it’s own. The anesthesiologist told me it would probably be elevated after the cocktail he used for the last surgery 3 weeks ago, and it was. This time I had a delayed reaction, over a day? But he told me not to chase it too hard with insulin. It’s still a white knuckled stressful experience to me all the same.
    Like you folks, just when I think I’m doing everything right with diet exercise and dosing, like it’s an exact science (A1C- 6.1- 6.3) since my diagnosis in 2009, yeah right, this hideous disease proves to me it’s a mysterious art form and bucks me on that pesky roller coaster ride. It leaves me thinking darn, is this Flexpen or BG meter broken or something? Not!
    All the calculations of carbs and sliding scale units, sometimes I feel OCD autistic, sigh!
    Another point I’d inject on your excellent article on eye care on blurriness symptoms. In addition to your recommendation of frequent dilated eye exams by a skilled ophthalmologist. I’d suggest your eye exams be earlier in the day, particularly your refractory exams for corrective lenses. schedule your exam on a good stretch of your BGL levels at optimal stable range. Nail your BGL for the exam and those new lenses. Check it in the chair, be on the markThat blurriness that you speak of might very well indicate your being in an un-healthy BGL range in the future. As you mentioned the effect on the inner ocular lens as well as any edema around or behind the retina could change your eyes focal point.
    Best wishes and be well!

    • dorthea jacquette

      I recently found out I’m also diabetic over weight and trying to lose weight…when I noticed problems with my right eye well working …it gets worse especially when my eye under flurence lights and poor light something in my eye stop working properly..like my hard to focus stuck in one position lots of pain in the eye.need help….notice all of that when sugar is low…having problems with people stay I looking at them funny.

  • Roberta

    I have been a diabetic for at least 10 years. It has been out of control up until recently. Normally, when my diabetic levels are high I get blurred vision. Now that my A1C levels have decreased where its getting under control, I am having blurred vision. My numbers for the past couple of months have ranged from 58 to 166. Went to the eye Doctor about my blurred vision and she informed me that she didn’t see any problems, therefore, it must be related to my diabetes being out of control for so long. Now when my numbers are low to normal, I have blurred vision. I am hoping that once I am under control for maybe 6 months that the blurred vision will cease; so far, its only been 2 months under control. The Doctor has increased my insulin dosage to ensure that it stays under control. I don’t agree (although I still do as advised, but when it’s 58, I won’t take any insulin at all.

    • mick

      Hi I gust been diagnosed with T.2 dibeties and have blurey vision can eney one tell me how long it takes to go away???

  • Drew

    Thanks for the great information. Something I’ve been struggling with is blurred vision after drinking tea. Whether it’s green, black, decaf, or even herbal teas, I get blurry vision after drinking tea. I think I get it a little after coffee, but it takes more coffee than tea to make it blurry. I thought it was the caffeine raising my blood sugar, but as I’ve said it even happens with caffiene-free teas. To be sure, I have tested numerous times and my blood sugar has been in normal ranges when the blurriness occurs.

    My endocrinologist and opthamologist both know of my symptoms, medications, suppliments, diet, and health, and don’t have an answer for me. I have had Lasik Eye surgery, and that eye doctor couldn’t figure it out either when I used to see him. Every time I get an exam, I have 20/20 vision or slightly better, even despite episodes of blurriness earlier that week or what have you.

    The blurry episodes haven’t been a problem before being diagnosed with type 1 diabetes. I am 29 and found out about 5 years ago. Not sure when I got the disease, but I believe it to be late-onset around 22 or 23 years old. The sudden problem with diabetes made me think it could be a drug side effect (insulin, or I also take lisinopril and synthroid), but the fact that it occurs within 1/2 to 1 hour after drinking tea makes me think otherwise.

    Blurriness occurs other times when I am not drinking tea, but I haven’t been able to isolate what food, behavior, or physiological condition(s) are associated with those episodes.

    • Jessica

      I have the same thing and no one seems to have heard of this before. Did you figure out why?

      • Drew Stafford

        Thank you both for your replies. Jessica, no I am still struggling to make sense of it. Anymore, my vision blurring has only gotten worse and more frequent.

        Ryan yes, it is even happened with herbal teas, which I do believe contain tannins. I don’t think doctors have reported on low iron, so I wonder if that is a temporary drop until I consume enough iron later on? I will start monitoring this and try to research it!

        While my blood sugar isn’t always in a good range, I monitor six times a day and make corrections even before my next eating. My A1C has been in the upper 6’s the last few years. It is just strange that there’s something other than all the causes listed in this article contributing, yet medical personnel can’t pinpoint it. I really do have a lot of faith in their medical knowledge, so I’m even more perplexed.

  • Christine

    Your articale does not mention it but i have heard that too much sugar can cause yellow eye is that true

  • Jennifer

    I have high blood pressure and family history of diabetes. I recently noticed a change in my vision after eating. I am wondering if this is a sign of diabetes. I have a Dr appt tomorrow and will hopefully find out soon. Your article makes sense and seems to relate to my issues.


  • Lalita

    Hello. Ive been wondering why I seem to get blured vision and find it hard to concentrate at times. I am over weight at 14 st (recently lost near 3st). I try to avoid processed food but recently let that slip a

    • David Spero RN

      Hi Lalita,

      High blood sugars can blur your vision, especially if you notice this after meals. Concentration problems could be a lot of things, but diabetes is one of them. Please focus on getting your diabetes under better control — if you lost 50 pounds, you can certainly lower your blood sugar. And check with a doctor or an eye doctor, because your blurred vision could be something else.

  • Kenny Hickerson

    I am 54 and weigh 126 . I spent 7 years in the NAVY on submarines . Some of the best food is on them. I never thought I would get diabetes . But 3 years ago my feet were burning . I come to find out I had nerapathy in both feet and legs. Now when my sugar goes below 60 my vision gets dark spots . I am going to make a eye doctor visit soon as it seems to getting worse.

  • Jesse

    I am a 23 year old type 1 diabetic, I was diagnosed when I was 13. Between the ages of 18 and 22 my diabetes was completely out of control while I was in college, due complete disregard for my health and heavy drinking. These past 5 months I have been keeping my glucose levels under control and my A1C within target range. I recently went to a retina specialist as advised by my endo doctor, the specialist told me I have thousands of little bleedings in my eye which was caused by years of neglect. He advised me to continue keeping my diabetes under control and will meet with me again in 5 months to check if the bleeding is stabilized or decreased, if not further treatment may be necessary, such as injections. Does anybody else have a similar situation? Can this be reversed or at least stabilized? Needless to say I am pretty scarred about the whole situation.

  • Joseph Illovsky

    I experience blurred vision every time my sugar levels drop, that’s my first sign have to eat. Type 2 diabetic.
    I had lasik 10 years ago, my vision was 20/20. 4 months ago I was squinting constantly, I now needed trifocals, two months later the prescription changed. It’s now another 2 months, and the prescription has changed again. All for the worse. Yet no one can give me a reason. ” everything is normal and my diabetes is under control “

    • Zdenek Hadascok

      Ain’t that something? My vision was getting progressively worse(blurred).Recently I’ve noticed,that my vision significantly improves after eating sugar. Note that I’m not even a diabetic. My blood sugar levels are all normal. Every doctor I’ve talked to said that it’s normal in my age (50).

  • David B Barrol

    I am having Type 2 Diabetes and have been taking Glipizide for a long time. My blood glucose level regularly increases during the daytime, and I am experiencing an obscured vision throughout the previous 2 months. I have consulted Goldberg vision correction centre and going to have my eye surgery on 23rd of this month.

  • Gayle Hardman

    Hi, I am over 55 and diabetic type 2 since 2000…always on Metformin + sometimes another pill added…only.hospital last year and this year + 3 months rehab gave me 70/30 insulin 2x per day …my sight blurred quickly and getting worse with daily insulin use here at rehab…one doc here said some get their usual sight back once body ued to insulin. ..is that true? I know spiked BS levels initially contributed to loss of vision, too, but has been controlled for a bit over 3 months now and no vision improvement. ..thanks, Gayle

  • Ana

    I started eating these protein bars called “ThinkThin”, they have sugar alcohol, 11g in one bar. I started eating them often , maybe once a day for a week and i started noticing by vision going bad. I couldn’t clearly see a face from down the hall when i knew i could just a week ago. Its really just when trying to see from a distance. I’ve stopped eating them for a week now, but my vision is still blurred.

    • john

      Sugar alcohol’s usually have a very small impact on blood sugars. However, different people can react differently to them but 1 bar a day containing 11g should not cause this. If I eat a bunch of sugar free candy with say a total of 40g of sugar alcohols my sugar only goes up a few point as opposed to 100 points or more if it was real sugar. I would think there is something else wrong.

      I would go to your Dr. and tell them about it to see if it is a diabetes related thing or something else. They should send you to an eye specialist, probibly an Ophthalmologist who can really look at your eye health. I wouldn’t wait, eyesight is important and you don’t want to risk loosing it.

      When I was diagnosed with type 2 I had really blurry vision, it took about 2 months to get back to normal, now it stays normal unless I go off my diet for a couple of weeks or more and my blood sugar starts getting up there.

  • Donald Campbell

    I notice when my sugar changes that I get sqiggaly lines in my vision and then I would eat an apple and it would go away. I have always had low sugar but never diagnosed with high sugar. Has anyone ever heard that?

    • Rachel Rodriguez

      Hello, I have been experiencing that since 2009. They usually visit me about 2 times a year and are followed by a headache. I’m told I might have diabetes. I’m checking that on Monday.

  • John Morel

    I have hypoglycemia and my vision is blurry most of the time. I am 61 years old. Today I bought some Ensure and my vision driving home was really bad. I decided to have one of the Ensure while stopped at a red light. No kidding within 30 sec. to a min. My vision cleared up. and I have been home now for about 35 min. And my vision is still way better. No double vision ( what I call ghosting )because it really isn’t double. Wow on the Ensure. I had no idea that my Hypoglycemia would do that to my eyes.

    • I didn’t either, John. Thanks for sharing that. You might want to talk with an eye doctor about it, but if your sugars are normal and your vision is clear, it’s up to you.

  • Troll

    I just found out about having diabetes and have been on Metaformin almost 2 weeks. Now that my glucose levels are going lower my vision is getting blurrier and blurrier everyday. With a high blood sugar I only needed reading glasses. Now I an’t see any distance, too blurry. I’m trying to find out if this is normal and things will change or if I need to seek out medical help right away. Still waiting on my Dr.s response.

    • Hi Troll, this happens sometimes if your eyes got used to the higher sugar. It makes your eyeball bigger, and they will now have to adjust because your eyeball is shrinking a little bit without the sugar pushing it out. This can take weeks to go away. A less likely possibility is that your sugar is going too low. If you’re having sweats or shakiness, check your sugar. You might need a medication change.

  • breanna eke

    I recently got diagnosed. Not sure if Im type 1 or 2 yet. When I was in the hospital I was on an insulin iv/drip and my vision drastically improved over night. I had 20/20 vision for about a week and half. Now I’m back to wearing my glasses. Not really sure what that is about. My endocrin app isnt until next month. My sugars are within normal range throughout the day even though I havent perfected eating completely healthy (had a few slips; just keeping it real). It seems that when my sugar drastically changed from high to low my vision improved. But now that my sugar is more controlled my vision has went back to how it was. Anyways going to my eye doc tomorrow to hopefully get them dilated.

    • Just an FYI–Type I diabetes is known as “Juvenile Diabetes”. It is primarily diagnosed when you are a child. If you are over 18, you were diagnosed with Type II diabetes, which is also known as “Diabetes Mellitus”.

      Editor’s note: Please note that “In the past 25 years, determining what type of diabetes a person has has become more of a challenge. In large part, that’s because more and more children and teenagers are now being diagnosed with Type 2 diabetes — the type that occurred predominantly in adults in generations past. Most of these children and teens are overweight. At the same time, it’s becoming clearer that Type 1 diabetes can occur at any age and sometimes occurs in people who are overweight.”

      • Melissa Simmons

        It’s actually about the functionality of your pancreas. With type 2 diabetes your pancreas produces insulin it just doesn’t go where it needs to. Type 2 can also be genetic or caused from lifestyle habits. Type 1 is when your pancreas does not function at all. Your body produces no insulin and you are completely reliant on injections. ✌️

      • William James Pratt

        I was diagnosed with Diabetes roughly 15 years ago. At that time I started out with meds and eventually was able to control my blood sugars by my diet. At that time I was diagnosed with type 2 diabetes. Which normally means your pancreas still produces insulin. Almost 2 years ago my endocrinologist changed my diagnosis to type 1diabetes because my pancreas no longer produces insulin. From what my doctor has told me that is the main difference between type 1 and type 2 diabetes. I have been insulin dependant now for 10 years, been on an insulin pump for 5 years.

  • Junie Germain

    How long does it take for the blurry vision to go away from having high blood sugar?

    • If you sugar is still high and bounces around, Junie, your vision might not clear up. If you’re talking about blurriness after sugars have come back down, that seems to take 1–3 months.

  • T1DiabeTix

    Yeah, when my blood sugar goes up to about 7 mmol/l or higher, my eyes begin to burn.

  • Rachel Hines

    @jonathangavia:disqus Would like to know how your vision has gotten since your last post 5 months ago. Did you notice that it has gotten progressively better? I am asking because I too am suffering this. Thanks!

  • Unless you are drinking tea that states it is “decaffeinated” black tea has 3x more caffeine than coffee. Just an FYI.

    • Ryan Doyle

      That’s completely inaccurate. A typical cup of black tea has about 1/2 the caffeine as the typical cup of coffee.

      • kdracco

        Unless you are measuring this yourself you are completely incorrect.
        Tea has more caffeine concentrated than coffee does. Regardless of what our opinions are, the
        caffeine is spiking your blood pressure and stressing the blood vessels
        in your eyes. It is why the Tea affects you more than coffee.

  • Betty Anderson

    I have been experiencing blurry vision when my Blood Glucose goes down to around 110. I am taking Metformin 1000mg and my blood glucose is around 140 – 180 right now. So I probably will have to take more after I see my doctor but the fact that when it goes to 110 I get blurred vision makes me worried to take more Metformin. When blood sugar goes back up after eating eye sight is fine (no glasses yet). I know this is not typical but not sure what to do or why it is happening.

    • James Baer

      I’ve been experiencing something very similar. I use injected insulin to control my diabetes, but aside from that fact, I’ve noticed that when I have my blood sugar down in the 90-120 range, my vision is terrible. When it jumps up to the 140-160 range, my vision is normal (or close to it). Having read the article, I’m guessing that it’s because it said that it can take up to 3 months of keeping your blood sugar in the normal range for your eyes to adjust. I see my primary care physician in a week and the eye doctor a few days after that. I plan to ask them about this.

      • Israel

        Hi! did you get a response to this question from your physician?

  • Jeff Anderson

    Got a huge wake up call yesterday morning. I didn’t feel right on Monday and I woke up to a case of double vision. I kept hoping it would normal up but never did. I was late for work and driving in Atlanta traffic with one eye was high adventure.

    As of bedtime it seams a little better. I’ve been being a bad boy on checking my sugars and watching my diet. Eating like I’m 18 again.

    Any guidance on treating this other than getting my sugars down? Thanks in advance.

  • Jim

    I’m diabetic and for the most part it’s under control but I was on an Antibiotic that spiked it so high that I panicked. I have it back under control now (pills not insulin) but when it went up I was able to see clearly without my glasses (reading) and as I got it closer to controlled I had to again rely on them, only issue is that both my eyes have a blur to them and now I have to use my glasses for everything. I have my yearly exam coming up this month but it’s driving me nuts.

    • evon markus (brown)

      I can relate a antibiotic hurt me also in many ways including my left eye both have had issues but the left is the worst 🙁

  • evon markus (brown)

    Eating so little can actually make your diabetes worst ! When you don’t eat your body tried to make up for it and it raises your suger my Dr told me water vegetables and water no fruit nothing with suger watch the carbs to bread or pasta anything like that