Lesson 2: How diabetes affects peoples vision

In this step, we’re going to explore how diabetic eye disease affects people’s lives in different ways, through four fictional case studies. These case studies will help you understand how people experience diabetes and interact with local health services.

As you read through, can you suggest what key steps can be taken at a health system-level or in your local setting to support people with diabetes similar to our cases here?

Jack was diagnosed with type 1 diabetes at the age of 10 and put on insulin treatment. He struggled to maintain a balanced diet, check his blood sugars and ensure he had taken the right insulin dosage. In his teenage years, he skipped meals and even insulin injections. He found going for regular check-ups tedious and began to miss them as well. Once he left home, he started to smoke and his diet worsened, and he forgot a lot of the advice he had received.

At the age of 30, he woke up one morning with a strange floater in his line of sight and after 2 days he decided to seek medical advice. Both eyes had haemorrhages with the right eye worse and he was given appropriate laser treatment but his sight continued to deteriorate. He lost his job and 2 years later, he was certified blind.

Comment on Jack’s case: Diabetic retinopathy is almost never seen in the first five years of diagnosis with type 1 diabetes or before puberty. The National Institute of Clinical Excellence (NICE) in the United Kingdom recommends that people with diabetes receive eye screening five years after diagnosis or at the start of puberty, whichever occurs earlier. This is especially important when blood sugar control is suboptimal either due to eating and exercise habits, irregularity with insulin treatment or poor adherence to medical follow up.

In many low and middle-income settings, the challenges of managing blood sugar include the limited availability and affordability of insulin, lack of cool storage facilities and poor diet. The Diabetes Control and Complications trial was a major clinical study conducted from 1983 to 1993. It concluded that intensive blood sugar control for type 1 diabetes reduces the risk for diabetic retinopathy by 76% and could slow the progression of retinopathy in 54% of cases.

Cristina is 33 years old and her eyesight has got a lot worse in the past few
months. She has had several pairs of glasses prescribed but is still unsatisfied with her vision. Recently, her vision deteriorated even further and she was diagnosed with cataracts in both eyes.

A cataract is the clouding of the lens of the eye, and typically affects people who are over the age of 50 years. As Cristina is relatively young to have visually significant cataracts the Optometrist asked her to have her blood sugars, blood pressure and cholesterol checked by the family doctor. He found that her HbA1c level was high which indicated that she has had diabetes for some time without knowing. Her blood pressure and blood cholesterol were also high. The doctor measured her weight and height and noted that she was overweight.

In the eye clinic, she was referred for retinal examination but it proved difficult to see the retina due to cataracts. Cristina was very anxious about cataract surgery and the potential changes in the retina. Her cataract surgery was delayed due to her poor control of her diabetes and blood pressure. Her vision continued to deteriorate and she became unable to drive and could no longer pick up and drop off her children or go and see her parents. Her life has changed completely. She knows she needs to improve things but is finding it difficult to get started and feels depressed.

Comment on Cristina’s case: Cristina’s story is not unique. Many people do not realise they have type 2 diabetes and are diagnosed only when they already have complications. Gillian needs to change her diet and her lifestyle so the cataract surgery can be done. Just the fact that she has diabetes more than doubles her risk of complications. If she has retinopathy, which we cannot see that at the moment due to the cataract, she might be five times more likely to develop complications than someone without diabetes, so preparation for the surgery will be the key to success.

Early detection for both diabetes and its complications is central to the
outcome a person may experience.

Frank has had type 2 diabetes for about 25 years, but it has never slowed him down. He has always been pragmatic about diabetes and at the time of diagnosis, he changed his lifestyle, started exercising, gave up smoking and only drank alcohol rarely.

None of these changes was easy as he was in a high pressured job and he
had to go out a lot with clients. Since retiring a few years ago, he has become more active by walking to the shops instead of driving and begun to eat more healthily. Therefore he was very surprised when he received a letter after his annual diabetic eye check-up telling him he needed to be referred for further assessment as the retinal changes were becoming more severe. He was aware of some retinal changes, but didn’t know that they can get worse.

In the meantime, his doctor told him that his blood sugar levels are high and that he should start on insulin. Although he has had diabetes for about 20 years, he didn’t expect to need to make further changes. He started insulin therapy which brought his blood sugar levels down very quickly and he got timely laser surgery to save his sight.

Comment on Frank’s case: Duration of diabetes increases the risk of developing diabetic retinopathy. Regular attendance for eye screening and careful self-management of diabetes (e.g. blood sugar control) become even more essential over time. This message is often lost on asymptomatic patients.

Further note: We are now seeing type 2 diabetes at a much younger age. At present retinal screening is offered to children only after the onset of puberty.

The lack of symptoms during the onset of diabetic retinopathy is often misunderstood by people with diabetes.

Mrs Begum is 34 years old, has two healthy children aged 12 and 8 and becomes pregnant with the third one. She’s had one miscarriage in between and no particular reason was found for that. She is of South-East Asian origin and her mother has diabetes as do both of her older siblings who have developed the disease in the past few years.

She does not feel any different to her previous pregnancies and attends her regular follow-up appointment. Tests finds that her urine has an excessive amount of sugar in it and she is asked to come back again, and the result is the same again. An oral glucose tolerance test shows that she has gestational diabetes.

Mrs Begum tries to control it through her diet and tablets but it doesn’t work – her blood sugar levels remain high. She’s told she needs to start on insulin to make sure that she has a chance of having another healthy baby.

At 36 weeks it is decided that she needs to have a planned Caesarean section at 38 weeks as the baby is too big already for its age. She has the baby and then keeps attending for follow-up as her chances of developing diabetes are high. She is not offered any eye screening during pregnancy.

Comment on Mrs Begum’s case: Gestational diabetes is one of the strongest risk factors for the subsequent development of type 2 diabetes. Up to 50% of women diagnosed with gestational diabetes develop type 2 diabetes within 5 years of birth. Pregnancy in women with pre-existing diabetes raises the risk of progression to proliferative retinopathy and these women must, therefore, be offered eye screening during the first antenatal period (8-12 weeks) and again at 24-28 weeks.

It is therefore recommended that Optometrists should conduct diabetic screening for all pregnant women visiting their clinics as the Optometrist might be the first to detect vision-threatening changes in the fundus

In summary, Diabetes is a chronic condition with long term impacts on people and their quality of life. To support people to manage their diabetes, health systems need to be appropriately prepared to provide a range supportive, diagnostic and curative services, including:

• Health education
• Early detection of diabetes
• Regular eye screening
• Early treatment of diabetic eye disease.