Pernicious Anaemia Society
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Some information please

I have recently gone on B12 injections every 3 months. My GP believed my B12 was caused by metformin so had to admit six months ago I never took it as it gave me stomach problems . The information I need is does anyone know if retinopathy can be caused by B12 deficiency? I am diabetic but it isnt severe but on my last screening I was diagnosed with Background diabetic retinopathy. I dont believe the cause is diabetes but even though I have searched I can find that B12 causes vision problems but not any particular eye problem like glaucoma or retinopathy. Thankyou

9 Replies

Hi tracywilliams03 I to have had the same dilemma.

I was diagnosed with P.A. (a form of B12 deficiency) over 45 years ago and I remember my then doctor telling me that when the nurses gave me my monthly cyanocobamalin injection that they would "look into my eyes". They never did - even longingly :) I even asked one nurse why she didn't "check my eyes" and she said she's never been told to nor had heard that she should do.

Two years ago I was diagnosed with Type 2 diabetes and within weeks was sent for a retinography test which came back reporting damage to my left eye. So, which caused what? The P.A. I'd had for over 40 years or the "new" diabetes?

I too queried the effect Metformin has on B12 levels but it doesn't really apply to me because of the injections.

I guess the jury's out on that one but I wish you well.

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Thanks for replying Clive. I am new to B12 deficiancy and dont know if I have PA. Unfortunately my primary care team blame it all on diabetes. I have been up and down B12 for about 5 years, so the Nurse has put me on an injection every 3 months. I dont have clue where I am with the retinopathy and B12 deficiancy.

I am treated as a type 2 diabetic but mine is hereditary and not recognised in the UK as anything other than type 2 which gets a bad press. My Grandma, my mum, her five sisters my two sisters and I and all my female cousins are diabetic and although some are overweight most are average or even underweight. I never really took my diabetes seriously did not bother with screening, I am blind as a bat anyway so often have an optician looking unlovingly into my eyes ;)

But my diabetic nurse had a rant at me (thorougly deserved) so I had a retinopathy screening and although clinically diagnosed as diabetic retinopathy I am not so sure.

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Whilst B12 can lead to sight problems the most commonly associated condition is glaucoma due to effects on the blood supply to the optic nerve.

There is a huge overlap in the symptoms of B12 deficiency and diabetes and symptoms of B12 deficiency often get overlooked as a result but in the case of the retinopathy I'm afraid it really is more likely to be the diabetes.

The mechanism for causing eye problems is similar overall - via effects on the cardio-vascular system - but the exact details of the process are, I think different in diabetes and B12 deficiency.

Were you prescrbed anything in addition/to replace metformin.

Sounds like you have a MODY diabetes variant (there is one that runs in my family but I don't have the gene so ...) Our variant has onset between 30 - 45 and doesn't necessarily respond well to metformin - because it is actually closer to type 1 than type 2 - so responds better to drugs that stimulte what little function is left in the pancreas.

My mother has very bad retinopathy and is blind in one eye and very little site in the other duet to diabetic retinopathy. She has never managed to control her sugar levels well (which may in part be down to having been treated as type 2 most of her life and taking metformin. My brother does much better (and can control his blood sugars quite well on sulphonylurea

These are a few articles on MODY that you might find it useful to share with your GP if you want to get your diagnosis corrected and correctly treated. It is possible to test to see which gene runs in the family but not sure if the NHS do that if you are UK based. You could try for a referral to a specialist though.


Unfortunately diabetes is a very serious condition and you do need to find and take a medication that works for you if you are to stop problems continuing to develop. If you have retinopathy that implies that you already have cardio-vascular problems - your kidney function is at risk etc.


There are a number of forums on JU that deal specifically with diabetes so you may find it helpful to join one of those


Thanks so much. Great info. Someone has mentioned to before about my diabetes being MODY as I said though not acknowledged in the UK and they dont gene test. My mum and her sisters and my Grandma were on insulin. I did not let on u til recently I was nit taking the metformin so no I have no been on an alternative. I try to control it with diet. I eat sensibly and am a partial vegetarian. I eat fudh and fowl but no red meat (another cause of vitamin B12 definciancy). But I eat a lot of fresh vegatables broccoli, cabbage, cauliflower, green beans etc. I have no way if measuring my diabetes so no idea if it us under control. I had my HBA1C 4 months ago and my diabetic nurse said they needed to re do the test becayse there had been a significant rise. I have had the retest but dont see her about the results until the 24th.

But thanks so much for you inforrmation, advice and links. Very much appreciated :)


if your hba1c is raised that means that you are not succeeding in controlling your diabetes through diet and exercise. hba1c is a protein that provides a very good marker as to whether your blood sugars have been elevated over a period of time. This is different from daily monitoring of blood glucose levels which can easily be done at home with a pin-prick test. All the members of my family who have diabetes have used pin-prick tests to monitor their levels - pretty sure that these were on prescription but if not I'm sure that a good pharmacist should be able to recommend something that isn't too expensive.

you are at serious risk of some very unpleasant conditions if you don't get your blood sugars under control - most of which are life threatening. Sorry if that sounds heavy but I just want to make sure you really understand just how serious the situation is.

Suggest that you speak to the diabetic nurse and/or your GP about monitoring and hope that you can find more support on one of the diabetes communities on HU.

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"and dont know if I have PA"

Risk factors for PA and B12 deficiency


When I searched online, I found some articles that linked b12 deficiency with retinopathy.


Thanks sleepybunny. Very helpful. I have diverticular disease, reflux disease and have been on Omeprazole for about 20 years so I think I can rule out pernicious aneamia. Seems like it us simply a case of not being able to absorb B12 becayse of my years on omeprazole and I am inclined to think that background retinopathy is not diabetes related. Once again thanks.


Hi again,

Have you ever had an IFA Intrinsic Factor Antibody test?

This can help to diagnose PA but the test is not always reliable and it is still possible to have PA even if IFA test result is negative (called Antibody Negative PA).

UK b12 documents

1) BSH Cobalamin and Folate Guidelines

Gives advice to UK doctors on diagnosis and treatment of B12 deficiency. I read the whole document.

Flowchart from BSH Cobalamin and Folate Guidelines

2) BNF British National Formulary UK B12 treatment

3) BMJ B12 article

4) More B12 info in pinned posts

B12 books

"What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper. Martyn Hooper is the chair of PAS (Pernicious Anaemia Society).

"Could it Be B12" by Sally Pacholok and JJ. Stuart (USA authors)

I am not medically trained, just someone who has struggled to get a diagnosis.


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