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Diabetic Retinopathy

Diabetic nephropathy is retinopathy, caused by complications of diabetes mellitus.


Presentation

Visual Signs and Symptoms

  • Microaneurysms: In most cases these are the earliest clinical abnormality detected. They appear as minute, discrete, circular, dark red spots near to but apparently separate from the retinal vessels [9].
  • Hemorrhages: They characteristically occur in the deeper layers of the retina, are round and regular in shape, and are called 'blot' haemorrhages. In hypertensive patients, superficial flame shaped haemorrhages may also occur.
  • Hard exudates: These are characteristic of diabetic retinopathy [9]. They result from leakage of plasma from abnormal retinal capillaries and can vary in size from tiny specks to large patches.
  • Cotton-wool spots: Most often seen in rapidly progressive retinopathy and hypertension, these spots represent arteriolar occlusions.
  • Venous beading: Sausage-like dilatation and increased looping of veins indicate widespread capillary nonperfusion.

Presenting Complaints

A patient may initially complain of blurred or fluctuating vision and difficulty in colour perception. This may be more evident in one eye than in the other. The patient may then complain of empty or dark areas and floating spots or lines in his vision. In severe form of this condition, the patient may eventually suffer from complete loss of vision.

Excessive Daytime Sleepiness
  • Long sleep duration (2.37 [1.16-4.89]), high risk of OSA (2.24 [1.09-4.75]), and excessive daytime sleepiness (3.27 [1.02-10.30]) were separately associated with VTDR.[ncbi.nlm.nih.gov]
Papule
  • Systemic findings included multiple, discrete, symmetrical, small yellow papules bilaterally in the axilla and inguinal region. Examination on presentation showed vitreous hemorrhage in his left eye, and vitrectomy was performed for treatment.[ncbi.nlm.nih.gov]
Background Retinopathy
  • One patient had mild background retinopathy on both eyes, with visual acuity of 1.0 and 0.7 after cataract extraction plus intravitreal triamcinolone injection.[ncbi.nlm.nih.gov]
  • Read more on treating retinopathy Background retinopathy Background retinopathy, also known as simple retinopathy, involves tiny swellings in the walls of the blood vessels.[diabetes.co.uk]
  • Proliferative retinopathy develops from background retinopathy and is responsible for most of the visual loss in diabetics. In this condition, new blood vessels grow on the surface of the retina and optic nerve.[snec.com.sg]
  • The categories of retinopathy are: Background retinopathy Background retinopathy occurs in the early stages and damage is limited to tiny bulges (microaneurysms) in the blood vessel walls.[diabeticretinascreen.ie]
Cotton Wool Spots
  • Cotton-wool spots are areas of microinfarction of the retinal nerve fiber layer that lead to retinal opacification; they are fuzzy-edged and white and obscure underlying vessels.[merckmanuals.com]
  • Screening for retinopathy is undertaken using conventional color fundus photography and relies on the identification of hemorrhages, vascular abnormalities, exudates, and cotton-wool spots. These can sometimes be difficult to identify.[ncbi.nlm.nih.gov]
  • Cotton-wool spots: Most often seen in rapidly progressive retinopathy and hypertension, these spots represent arteriolar occlusions. Venous beading: Sausage-like dilatation and increased looping of veins indicate widespread capillary nonperfusion.[symptoma.com]
  • Cotton wool spots 2. Venous beading 3. Intraretinal microvascular abnormalities (IRMA) in at least 2 contiguous overlapping photographic fields 4.[bu.edu]
Retinal Hemorrhage
  • We present the case of an early stage diabetic retinopathy patient presented with retinal hemorrhages in the superior temporal area and disc hemorrhages of disc nasal area. The patient was diagnosed with mild NPDR on fundus examinations.[ncbi.nlm.nih.gov]
  • The first signs of nonproliferative retinopathy are Capillary microaneurysms Dot and blot retinal hemorrhages Hard exudates Cotton-wool spots (soft exudates) Hard exudates are discrete, yellow particles within the retina.[merckmanuals.com]
  • Moderate-to-severe retinal hemorrhages and/or MA’s Patients were excluded if they had undergone previous PRP or had a macula-threatening TRD.[bu.edu]
  • Macular edema or retinal hemorrhage may be visible on funduscopy. Diagnosis Funduscopy Color fundus photography Fluorescein angiography Optical coherence tomography Diagnosis is by funduscopy.[merckmanuals.com]
  • Fig. 1 A photograph of a normal retina Fig. 2 Photograph of a retina showing proliferative retinopathy – (v) growth of new unnatural blood vessels, (h) retinal hemorrhage.[betterhealth.vic.gov.au]
Macula Edema
  • The swelling in the macula (edema), can be caused by a few leaking vessels or many scattered throughout the macula. This may cause slight to very severe blurring of vision.[arleoeye.com]
  • When the macula swells with fluid, a condition called macula edema, vision blurs and can be lost entirely.[thevisioncarecenter.com]
  • Macula edema is noted when areas of your retina are shown to contain spaces filled with fluid. Treatment and Drugs In mild cases, treatment for diabetic retinopathy is not necessary.[umkelloggeye.org]
  • The detection of people with untreated vision-threatening retinopathy (defined by the presence of PDR or macula edema) is of concern, given that it is recommended that all people with diabetes have their eyes examined every 1 to 2 years ( 30 ).[doi.org]
Visual Acuity Decreased
  • Her visual acuity decreased to 0.5 OU, and ophthlamoscopy showed severe DME in both eyes.[ncbi.nlm.nih.gov]
  • Postoperatively, visual acuity decreased to no light perception because of neovascular glaucoma complications and lack of proper follow-up.[ncbi.nlm.nih.gov]
Social Isolation
  • Significant visual deficit from diabetic retinopathy can lead to social isolation of older individuals by limiting driving, the ability to leave the home or remain in the home safely, and the ability to watch television or read.[ncbi.nlm.nih.gov]
Altered Mental Status
  • General anesthesia or sedation can mask a hypoglycemia-altered mental status. Acute hypoglycemia might result in permanent brain injury.[ncbi.nlm.nih.gov]

Workup

Work up includes a complete history and physical examination. The following tests should be conducted:

Laboratory Tests

  • Complete blood count
  • Resting blood sugar
  • Fasting blood sugar
  • HbA1c levels
  • Liver function tests

Imaging Studies

  • Flouroscein angiography: This is a test in which pupils are dilated and photographs of the vessels are taken. Then a radiocontrast dye is injected and photographs are taken again once the dye has perfused to all eye vessels. 
  • Optical Coherence Tomography (OCT): OCT provides us with cross sectional images of the retina which help on both identifying retinal thickening, if any, as well as monitoring the progress of treatment. 
  • B-scan Ultrasonography may also be done.

Test Results

Test results indicate the type and degree of severity of diabetic retinopathy and appropriate treatment can be started.

Treatment

Medications

Multiple doses of intravitreal injections of anti-VEGF drugs such as bevacizumab show good results [10]. Similar dugs like Ranibizumab and a corticosteroid Triamcinolone may also be given.

Photocoagulation

In cases of nonproliferative DR, laser photocoagulation may be used to treat macular edema due to vascular leakage.
In patients with proliferative diabetic retinopathy, panretinal photocoagulation is used to spare the macular area and treat the entire diseased retina.

Vitrectomy

This procedure may be used in some patients with proliferative diabetic retinopathy.

Cryotherapy

This procedure may be used when the patient already suffers from other eye diseases like cataracts, etc.

Blood sugar level control

This is the primary mode of controlling the progression of retinopathy. By bringing blood glucose to normal levels, edema and other such conditions involved in diabetic retinopathy can be lessened.

Prognosis

The longer a person has diabetes, the higher his chances of developing diabetic retinopathy [8]. If a person has been diagnosed early, he would have well defined leakage and good perifoveal perfusion. His vision loss would be mild and exudates would be minimal. In such cases, prognosis is favourable as with the right control and treatment, the progression of the disease may be halted.

If on the other hand, a patient with diabetic retinopathy also has hypertension and/or kidney disease, and has already suffered from irreversible macular ischemia and edema, prognosis is bad.

Complications

Complications include all the factors that may worsen the ischemic state of the eye such as:

Etiology

As the name indicates, the primary cause of diabetic retinopathy is diabetes. In type I diabetes mellitus, chances of developing this condition is comparatively less. In patients with type II diabetes mellitus, however, incidence of this condition is directly proportional to disease duration.

Other causes include hypertension and hyperlipidemia which may exacerbate preexisting diabetes and increase the risk of developing diabetic retinopathy. Studies reveal that pregnant women that have this condition have a 4-5% chance of progression to a more severe stage.

Epidemiology

Diabetes is responsible for approximately 8000 eyes becoming blinded each year, meaning diabetes is responsible for 12% of blindness [2].

A recent estimate of the prevalence of diabetic retinopathy in the US showed a high prevalence of 28.5% among those with diabetes aged 40 years or older [3]. Clearly the longer a person has diabetes, i.e the older a person is, the more likely he is of developing retinopathy.

Sex distribution
Age distribution

Pathophysiology

The retinal vasculopathy of diabetes mellitus can be classified into background (preprofilerative) diabetic retinopathy and proliferative diabetic retinopathy [4].

Pre-Proliferative Diabetic Retinopathy

Hyperglycaemia induced intramural pericyte death and thickening of basement membrane leads to vascular wall incompetence. These damages change the formation of the blood-retinal barrier and also make the retinal blood vessels more permeable [5]. Smaller vessels may occlude and the weakened walls of the larger vessels may dilate. As a result microaneurysms and macular edema occurs.

Proliferative Diabetic Retinopathy

Retinal ischemia can result in up-regulation of pro-angiogenesis factors such as VEGF and lead to retinal angiogenesis [6]. Retinal neovascularization may be accompanied by the development of a neovascular membrane on the iris surface, presumable secondary to increased levels of VEGF in the aqueous humor [7]. Gradually, scar tissue develops which may cause retinal detachment and/or build up of intraorbital pressure leading to glaucoma and optic nerve damage.

Prevention

  • […] conclusion regarding an overall benefit of intervening on blood pressure solely to prevent diabetic retinopathy.[doi.org]
  • Treatment with laser photocoagulation is effective at preventing severe vision loss; thus, diabetic patients should be referred for regular screening by an ophthalmologist.[ncbi.nlm.nih.gov]
  • That’s why it’s vital that you know why you’re at risk of eye problems and what you can do to prevent them.[diabetes.org.uk]

Summary

Diabetes mellitus is a metabolic disorder that results in excess glucose in the blood. This excess amount of glucose causes widespread complications.

The most common and potentially most blinding of these complications, however, is diabetic retinopathy (DR) [1]. In this condition, a person retinal vessels suffer ischemia and damage due to high blood glucose levels resulting in visual loss and in the worst case - blindness.

Patient Information

Diabetic retinopathy is a complication of long standing, and often uncontrolled, diabetes mellitus. It is caused due to raised glucose levels in the blood which damage the blood vessels of the eyes, leading to first blurred vision and finally blindness.

If you are diabetic and feel that your visual power has decreased, you should schedule a consultation with an eye specialist immediately.

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Last updated: 2019-07-11 21:08