www.diabeticretinopathy.org.uk

Diabetic maculopathy for professionals

David Kinshuck

 

Introduction

The treatment for diabetic macular oedema (DMO) is changing

Poor diabetic control

Many ophthalmologists have wondered why some patients who present with severe maculopathy do well and some do badly.

  1. If a patient presents with severe maculopathy but their diabetes is reasonably well controlled, (HbA1c < 9% and blood pressure reasonable) and it has been for some time, with laser/anit-VEGFs/further improvement of their diabetic control they may do very well, keeping central vision and be able to read, though often not good enough to drive.
  2. If a patient with similar severe retinopathy presents, and their HbA1c >11%, and their BP 200/120, they are likely to do very badly, even if their control is improved. Good control is essential in the long term, but nevertheless in the short term the retinopathy will get worse. see. Case 57 
  3. An extremely low blood pressure will prevent some deterioration (as low as possible whilst the patient feels well, perhaps <115mmHg systolic.)  BP & maculopathy see 2013
  4. Most patients will be in between, that is there will be some response to laser/anit-VEGFs, but their retinopathy may deteriorate a little as they improve their diabetic control.
  5. Smoking quadruples the retinopathy, and stopping will be extremely helpful.
  6. Statins are now recommended for nearly every type 2 diabetic patients, where well tolerated. They will help exudates disappear, but have much less effect on the oedema itself. (Exudates themselves can cause scarring and loss of sight.) Fibrates may be more effective than statins. Lipid lowering is essential BJO 2010.
  7. Massin (EASDec 2005 meeting)  reported that macular oedema can be temporary. It fluctuates during the day.
    She presented a patient who had macular oedema after laser for proliferative retinopathy (type 1 diabetic, diabetic about 20 years. He did not look after himself..he overworked, ate a little too much, and took no exercise. One eye was treated with triamcinolone twice and improved temporarily each time. Whilst having these injections, he did start to exercise, and lose weight etc, and the macular oedema that was bilateral (despite the triamcinolone in one eye) resolved and his sight improved to 6/12, so he was able to read and drive. (anit-VEGFs would be the preferred treatment now.)
  8. Thus the key is to persuade patients and their professional carers not to allow the HbA1c to rise at any stage of the diabetes, and to aggressively treat blood pressure. In this way if retinopathy does develop it should respond better to laser.
  9. BJO 2011   Reduced renal function case 57.  
  10. Increased macular thickness even in the absence of oedema Eye 2012
  11. sleep apneoa plays a significant role

A treatment plan

Foveal avascular zone (FAZ)/macular ischaemia

If the FAZ enlarges, vision is reduced, see & see. If vision is reduced and there is no oedema clinically, this is the likely cause: a fluorescein angiogram (FFA) will confirm this. Laser is not helpful. Laser is for macular oedema, seen with OCT or clinically with a slit lamp, or FFA. Avastin is less effective if the FAZ enlarges ('ischaemic maculopathy'). The ischaemia leads to foveal atrophy. Fundus autofluoresence is helpful in determining the degree of foveal damage (see 2002) , but is seldom available.

 

The importance of OCT & types of macular oedema

 

 

 

OCTs are very useful to determine which type of macular oedema is present. These are diagrams illustrating the text in a paper by Markomichelakis. There are 3 basic patterns, which often occur in combination: diffuse, cystoid, and serous detachment. This paper really examined uveitis patients, but reported similar findings in diabetic retinopathy.

Sponge type diabetic macular oedema responds better than cystoid  Retina 2013.  Response best sponge (=diffuse on this page) > cystoid > subretinal fluid, and best with short duration of diabetes (photo).

OCT is crucially important in deciding treatment, see see .and is the main guide for the use of anti-VEGF drugs (primarily Avastin)...if the oedema reduces the drug has worked and is a very useful guide.

Extra-foveal vitreous traction is linked to macular oedema. Ophir 2009  This is the case even in non-diabetics Fatum 2009. 33% of patients with diabetic mac. oedema have VMT (Vitreo-macular traction), Eye 2010.

Diffuse oedema responds best to anit-VEGFs. Cystoid usually has a very limited response, and serous detachment also has a poor response. The effect of treatment tis best in the first 6 months and thereafter depends on the injection frequency.

 

Defining and classification of diabetic macular oedema

 

Vitrectomy for diabetic macular oedema (DMO)

It is best used with OCT helps if there is vitreomacular traction (VMT), see, but not eyes with a PVD already (right), but some patients do get worse see. It is only really helpful if the diabetes (HbA1c/BP) is well controlled and the retinopathy is stable...no haemorrhages or exudates etc.

With vitrectomy with VMT. 50% patients gain 2 lines. 33% of patients with diabetic mac. oedema have VMT (Vitreo-macular traction), Eye 2010; vitrectomy may help in this group particularly.

On the other hand, this walled cysts and subretinal fluid as part of the VMT indicate sight will not be improved with vitrectomy. Nottingham 2011: vitrectomy reduces DMO in the short term, but then it recurs.

OCT appearance....vitreous attached to fovea

Left: VMT, vitrectomy may help. Right, a straightforward PVD, vitrectomy will not help reduce macular oedema.

vitrectomy for macular oedeam...thin walled cyst, poor result

 

If the 'wall' of the elevated retina
is too thin,
results will be poor as there is too much atrophy.

macular oedema with subretinal fluid

 

If there is subretinal fluid, surgery will not improve vision.

Intravitreal steroids