Diabetic Retinopathy

Overview

Eye Cells

Diabetes

  • A chronic metabolic disease characterised by insufficient insulin secretion (type 1 diabetes) or by a decrease in the effects of insulin on tissues (type 2 diabetes).
  • Insulin is the hormone which regulates the concentration of sugar in the blood. Hyperglycaemia, or high concentrations of sugar in the blood, is a common effect of uncontrolled diabetes and over time can lead to damage to many organ systems.
  • Complications: Diabetes can lead to damage to the heart, blood vessels, the eyes, kidneys and nerves:
    • Increased risk of cardiac disease and of stroke: 50% of diabetic patients die from cardiovascular disease,
    • Neuropathies,
    • Diabetic retinopathy,
    • Renal impairment.(1)

Diabetic retinopathy

  • A degenerative disease of blood vessels of the retina.
  • Occurs in persons with diabetes.
  • Caused by excess concentrations of sugar in the blood, characteristic of diabetes, which damages the small blood vessels which supply the retina with nutrients and oxygen.(2) 

Diabetes

  • A very wide-spread disease: about 350 million persons world-wide are affected (1).
  • Affects about 4% of the population in France, i.e. more than 2.5 million persons (3).

Diabetic retinopathy

  • A major case of decreased visual acuity in 2002: 4.8% of cases of blindness (4).
  • In France, 35 to 40% of diabetic patients have retinopathy, i.e. about 800,000 persons (5).
  • It is one of the most common complications of diabetes (4):
    • 100% of the population of patients with type I diabetes will be affected by diabetic retinopathy after 10 years’ progression of diabetes
    • 33% of the population of patients with type II diabetes will be affected by diabetic retinopathy after 20 years’ progression of their diabetes
  • A disabling complication:
    • 33% of diabetic patients with blindness-related complications will become permanently blind.  
  • Importance of regular checks
    • 10% of diabetic patients have problems of vision.
    • Detection and early treatment of damage to the retina would make it possible to prevent over 95% of cases of decreased visual acuity in diabetic patients (6).

Risk factors

  • Factors which promote the occurrence of diabetic retinopathy and accelerate its progression:
    • Duration of diabetes
    • Poor control of glycaemia
    • Arterial hypertension
    • Smoking
    • Dyslipidaemia
  • Enhanced risk of progression of diabetic retinopathy in pregnancy in pregnant women (2) (4).

Prevention

  • Regular ophthalmology consultations and at a frequency advised by a practitioner:
    • Generally, at least once a year according to recommendations of the French National Authority for Health (HAS). (3)
    • In case of observation of the least visual anomaly.
  • Measurement of glycaemia:
    • Rules of hygiene and diet: Regular physical activity, weight loss in case of overweight, balanced diet
    • In possible combination and under medical advice with medical treatment.
    • Determination of glycaemia curve, if specified by the doctor. (1)

Clinical Presentation

Video 3.1: Non-proliferative retinopathy​

Video 3.2: Proliferative retinopathy​

Non-proliferative diabetic retinopathy

In the beginning, the disease is characterised by an increase in permeability and dilatation of blood vessels, as well as by micro-aneurysms, small haemorrhages, exudates, ischaemia and macular oedema.(2)

Proliferative diabetic retinopathy

With passage of time, micro-aneurysms and haemorrhages become increasingly frequent. The retina is increasingly less well-supplied with oxygen and nutrients. In a compensatory mechanism, new blood vessels form on the surface of the retina. The former are fragile and can cause an intravitreous haemorrhage. Retinal detachment can also occur. (2)

Macular oedema

  • Can occur in the proliferative or the non-proliferative form.
  • Accumulation of fluid or blood in the macula because of the patency of blood vessels.
  • The most common cause of blindness associated with diabetic retinopathy (2)

Video 3.3: Visual symptoms​

Visual symptoms

  • In the beginning, retinopathy often is not accompanied by any visual symptom. With progression of the disease, macular oedema can cause a decrease in visual acuity. 
  • At a later stage, vision can become blurred and the visual field can be sprinkled with black spots or light spots.
  • Decreased vision normally is of progressive and slow onset. Except in case of intraocular haemorrhage or detachment of the retina or where loss of vision is rapid and very pronounced. (2)

Diagnostic

World Cells

Diagnostic approach

  • Importance of regular ophthalmological follow-up for patients who are diabetics. (3)
  • Taking into account systemic parameters (hyperglycaemia, hypertension, etc.)
  • Conduct of a complete ophthalmological assessment with measurement of visual acuity and of intraocular pressure.
  • Diagnosis is established after fundoscopy. (2)
  • Importance of undergoing retinographs (colour photographs of the eye background) (retinography) to evaluate the stage of retinopathy. Possible postponed reading. (3)

Laboratory tests:

  • Fluorescein angiography:
    • Performed using a retinograph of photographs of blood vessels in the retina after administration of a contrast medium.
    • Precautions related to use of fluorescein (allergic subjects).
      • To determine the degree of extension of the retinopathy and perform follow-up of treatment.
  • OCT (Optical Coherence Tomography):
    • Technique based on reflection of infrared light.
    • Is always painless, does not require injection of any contrast medium.
    • Makes it possible to assess the thickness of the retina by providing images in section ranging from the superficial layers to the deepest layers:
      • To evaluate severity of macular oedema and response to treatment. (2)

Treatment

Eye Cells

General measures

It is essential to measure glycaemia and blood pressure. (2)

Management of macular oedema

  • Intravitreal injection of anti-VEGF
  • +/- Subthreshold laser therapy 577 nm

 Management of complications of proliferative retinopathy

  • Laser photocoagulation therapy: pan-retinal photocoagulation (PPR)
    • Indicated in case of a high risk of intravitreal haemorrhage, of major pre-retinal neovascularisation or of neovascularisation of the anterior segment.
    • A therapeutic procedure designed to eliminate blood vessels which have formed in the peripheral retina: consists of projecting a thin and intense light bundle produced by a laser light on the affected areas.
    • Technique enabling to reduce the risk of severe loss of vision.
    • Disadvantages related to destruction of the peripheral retina (reduction of visual field, poor night vision, occurrence or worsening of macular oedema.)
  • Surgical treatment: vitrectomy
    • Reserved for persons with vitreal haemorrhage or a detached retina.
    • Surgery consisting of removing all or part of the vitreous.
    • Designed to remove blood present in the eye, to destroy new-formed vessels and if necessary to re-attach the retina. (2)

References

Cells
  1. Organisation mondiale de la santé. Diabète. Aide-mémoire N°312. http://www.who.int/mediacentre/factsheets/fs312/fr/ . Novembre 2014
  2. Porter RS, Kaplan JL. Chapter 68. Retinal Disorders. The Merck Manual of Diagnosis & Therapy, 19th Edition,  Merck Research Laboratories 2011, p.724-726.
  3. Haute Autorité de Santé. Dépistage de la rétinopathie diabétique par lecture différée de photographies du fond d’œil, Argumentaire. Décembre 2010.
  4. Organisation mondiale de la santé. Prévention de la cécité et des déficiences visuelles.  Maladies oculaires prioritaires. Rétinopathie diabétique. http://www.who.int/blindness/causes/priority/fr/index6.html
  5. Massin P. Nouveautés sur la rétinopathie diabétique. Médecine clinique endocrinologie & diabète. Hors série. Confrontations Endocrinologie - Diabétologie Sud-Franciliennes. Mars/Avril 2006, 32-9.
  6. Rabasa-Lhoret, Avignon F, Monnier L et al. L’impact socio-économique du diabète sucré de type 2. Sang Thrombose Vaisseaux 1999;11:587-95.