Drugs to treat diabetic retinopathy
There are 3 drugs. Eylea is very slightly longer lasting. Avastin is the cheapest and almost certainly just as good as Lucentis which is in popular use. The procedure is discussed.
The drugs reduce macular oedema (leakage in the cnetral retina) and proliferation (blood vessel growth) in diabetic retinopathy, but their effect usually wears off. To keep good sight in the long term, the diabetes, blood pressure (BP) and smoking must be controlled: the drugs are very useful for use whilst patients are trying to control their diabetes and BP targets
The risk of anti-VEGF treatment is small
- 1/1000 serious infection
- Very small risk of other less serious problems such as cataract and retinal tears.
- About 50% of people develop a rise in eye pressure that needs anti-glaucoma eye drops for a few months, or perhaps longer.
- 16% develop a significant pressure rise, needing drops and diamox tablets (diamox is best avoided in renal failure patients)
- in some studies 7% develop a serious pressure rise that may require glaucoma surgery (this is about half of the 16% above) Eye 14
- sometimes the eye pressure is permanently raised, although on some occasions it is just temporary
- the pressure rise may develop in a week (and is so is likely to be troublesome). But it may not present until 4 weeks. If you have a normal or near-normal pressure at 4 weeks you are unlikely to develop severe glaucoma later.
- The pressure rise is not always related to the patient..we have had one patient who had both eyes injected (on separate occasions), but only one eye developed a pressure rise.
- The benefits wear off if injections need to be repeated.
- See some results...benefits may last 2 years. Other results, no long term gain.
- Expect a bigger pressure rise with the second eye
Renal Failure or Diamox allergies
Diamox is a drug given to lower eye pressure, and is used in a lower dose with renal failure, If this drug cannot be avoided, you must take precautions..as your your ophthalmic team may not realise you aware you have renal failure.
As intratvitreal steroids may put up your eye pressure, the treatment is generally avoided in glaucoma patients. However, on most occasions the pressure rise can be treated, although rarely surgery is needed.
- Anti-VEGF injections started early before severe macular oedema develops will maintain good vision.
- Although for good sight without injections good diabetic control, low blood pressure, not smoking, (targets) is needed.
- Occasional laser will be needed.
- A little chronic macular oedema can be accepted and not treated if the diabetes is well controlled. But if the diabetes, BP, and smoking are not controlled, the condition will get worse, so treatment will ideally start before the condition gets too severe.
- If there is absolutely no response as measured by the OCT injections, and if the patient has had cataract surgery, intravitreal steroids may be best. If the patient has not had cataract surgery then surgery and Iluvien might be best.
- Similarly if the condition is severe, intravitreal steroids may be best; if the patient has had cataract surgery, intravitreal steroids may be best. If the patient has not had cataract surgery then surgery and Iluvien might be best.
- Anti-VEGFs injections will usually stop proliferative retinopathy. In th UK they are used in addition to laser; if there is a vitreous haemorrhage and flat retina (the haemorrhage stops the laser working); or if most of the retina is lasered. Many richer countries rely mainly on injections, and UK retina experts would like to move in this direction.
- Eyes with vitreous traction may develop more traction on the retina.
Unfortunately the effect of these drugs is just weeks. Here is my interpretation of Macugen's (an older drug now withdrawn) results:
Visual acuity improved whilst the injections are given, but starts to deteriorate when they are stopped. However, if the blood pressure is lowered aggressively and diabetic control improves, ophthalmologists hope for much longer benefit.
All these are injections in the eyeball itself, all with a risk of glaucoma. Triamcinolone is a regular fluid injection, Osardex and Iluvien are slow-release inserts.
- triamcinolone is useful for short term use, particularly for post-cataract macular oedema. There is a considerable risk of glaucoma, see details.
- Triamcinolone 40ml, 0.1ml=4mg
- So need 2mg = 0.05mls, same volume as Lucentis and Eyela, same size syringe
- Shake first just before draw up as there would otherwise be an uneven distrribution of the drug
- Osardex helps, but 100% patients develop cataracts, and there is a considerable glaucoma risk, details. It lasts 16 weeks.
- Iluvien is licensed for use after the cataract has been removed, details. It lasts 3 years.
This is essential even with the new drugs. See targets