Diabetic Retinopathy

Introduction

This is the term given to early damage of the retina in diabetes. Your sight should be perfectly good at this stage. A doctor examining your eye will notice tiny abnormalities. The tiny blood vessels in the retina, the capillaries, become damaged, from the diabetes. The blood vessel damage is generally visible on photographs. In the UK, nearly every person with diabetes should have yearly photos taken.

In Birmingham these are taken by about 40 optometrists across the city, but in other places technicians take the photos, often with mobile cameras. The photographs are examined by the optometrist or photographer, and patients with significant damage are referred to hospital clinics. Your pupils have to be dilated  for this examination, and you are often advised not to drive until the pupils have returned to their normal size.

What the doctor sees

A doctor or optometrist may see ‘dots’ and ‘blots’. The dots are some capillaries that have enlarged, that is the the tiny blood vessels enlarge to form microaneurysms. The blots are tiny haemorrhages, that is tiny spots of blood, on the surface of the retina. There are also leaky areas, called exudates.

background diabetic retinopathy...dot and blots

This is the view a doctor sees looking into your eye. The small red dots are ‘microaneurysms’, tiny damaged capillaries. The bigger red blobs are small haemorrhages, little flecks of blood. The white dots are exudates (leakage). Your sight is not affected at this stage.

What does it mean if you have ‘background retinopathy’?

The number of microaneurysms, the little red dots the doctor sees, indicate the likelihood of more severe problems in the years to come.  As the damage is mild at this stage, your sight will be nearly perfect. However, the condition does progress.

It occasionally progresses quickly, but usually changes slowly. If your diabetes and blood pressure are well controlled, and have been all the time you have had diabetes, changes should be very slow are controlled. Unfortunately for many people with diabetes the retinal damage increases, and maculopathy or proliferative retinopathy develop over a few years.

Background retinopathy generally means your diabetes is not controlled as well as it might be. If you have been diabetic 30 years, even with the best control, these may develop. But most people who have background retinopathy have not been diabetic that long, and need better control as per these targets.

Types & progression of background retinopathy

Retinopathy progression appears to follow different patterns. Some patients develop leakage (such as macular oedema), and others develop capillary closure (which also causes loss of sight).

The number of haemorrhages and microaneurysms indicate progression. If they increase in number the retinopathy is getting worse. Dropping blood pressure to the targets above will slow down progression right away. But if there is significant retinopathy, it takes 3 years of low blood sugars (eg HbA1c

Targets

Looking after your diabetes will prevent or delay problems:

lifestyle

  • 30-120 minutes exercise a day ,
  • moderate alcohol consumption only,
  • avoid obesity if possible,
  • balanced diet including
  • 9 portions of vegetables or fruit a day (9 for men, 7 for women),
  • minimal of animal or ‘hard’ vegetable fats,
  • low salt,
  • Alcohol should be limited to one drink or unit a day, six days a week (Mukamal 2004). More than this leads to brain damage.
  • Oily fish such as sardine, salmon, tuna, trout, at least twice a week (small amounts are fine…not a whole salmon!).
  • Fibre and healthy fats in the diet slows down retinopathy. No transfats and minimal saturated fat.

blood pressure

  • 130/80  or preferably less
  • (120/75 ..home monitoring)
  • 125/75 or less if protein in urine present (115/70.. home monitor)
  • ACE inhibitors or Angiotensin Receptor Antagonists unless young/pregnant/very low blood pressure/poorly tolerated
  • The lower the better in macular oedema, as long as you feel well.
  • An ideal pressure is below 115 (systolic, first number) for healthy people.
  • Home monitoring blood pressures should be 10mmHg (systolic) and 5mmHg (diastolic) lower.

HbA1c

  • 7.5-6.5% or less with very few or preferably no hypos. These (or slightly lower) levels are the best to prevent complications
  • If hypos develop, seek expert advice from your diabetes nurse/doctor.
  • if your HbA1c is high (say 11%), then the next step may be to achieve 9%….in other words, and any improvement is helpful, gradually reaching lower levels above.

sudden decrease in HbA1c

  • A sudden improvement in control (HbA1c drop of 3%) will lead to a temporary rapid increase in progression of retinopathy: laser may be needed.
  • Good control is important in the longer term, that is after about 2 years. When people who control their diabetes well will be better off after this period.
  • A temporary increase in retinopathy is most common when starting insulin for the first time, especially if the diabetes is very badly controlled when you start the insulin.

cholesterol

  • statins are recommended whatever the cholesterol, if well tolerated age>40y
  • A fibrate such as fenofibrate is advisable in nearly every person with retinopathy. They reduce retinopathy progression 40% (Fenofibrate 200mg od). We now recommend these for all adult patients, and they can be used in addition to a statin.
  • LDL
  • Avoid if pregnant, GFR
  • If GFR low but still >15, need a lower dose.

smoking

  • smoking  20 a day triples/quadruples retinopathy
  • passive smoking may double retinopathy: room-mates inhale at least 25%

insulin

  • multiple dose insulin, using a protocol such as using lantus (long acting) and rapid acting (novarapid/humalog) is normally superior to twice daily. (This is controversial.)
  • Insulin pumps generally produce better control still, but are harder to use.

education

  • everyone with diabetes should attend an education course, such as DAFNE (insulin) , DESMOND (type 2 at diagnosis), or XPERT (type 2). Primary Care Trusts are obliged to send you on such a course, but very few patients have ever attended one. If you have not been on one, discuss this with your diabetic team. Get a diabetes buddy.

sleep apnoea

  • this contributes to macular oedema and loss of sight (Schwartz, 2006), and many serious problems.
  • It is common in diabetes, particularly if you are overweight. Do you have sleep apnoea?

glucose level

  • 5.0-7.2 mmol/l before meals
  • no serious hypos

Glitazones

  • Rosiglitazone and pioglitazone should not be used if there is significant retinopathy, and certainly not if macular oedema is present, as they increase macular oedema and fluid retention. Lirglutadite and Exenatide are drugs that can be used instead low also lower weight (they are injections.)

hypoglycaemia

insulin users need to avoid serious hypoglycaemia. Expert help is usually needed if episodes are severe/frequent.

neuropathy

issues

many patients receive totally inadequate care BMJ 11. Some call this ‘institutionalised neglect’.

Photo

This photograph shows ‘circinate’ retinopathy. Laser treatment is needed (early maculopathy). Good diabetic control is needed. Circinates further from the macula would be classified as ‘background’ or early none-proliferative retinopathy.

circinate retinopathy...good control is needed to prevent serious eye problems in 3-5 years

Circinate retinopathy…good control is needed to prevent serious eye problems in 3-5 years. There is a circle of exudates surrounding a leaky area, with a dot haemorrhage or microaneurysm in the middle.