Diabetes mellitus currently affects more than 171 million persons worldwide, and this scale is estimated to touch 366 million by 2030. The eye is the most commonly affected organ by diabetes leading to Diabetic Retinopathy (DR) 1)Wild S, Roglic G, Green A, Sicree R, King H. Global prevalence of diabetes: estimates for the year 2000 and projections for 2030. Diabetes Care. 2004;27(5):1047–1053. doi: 10.2337/diacare.27.5.1047. [PubMed] [CrossRef]. More than 75% of patients who have diabetes mellitus for more than 20 years will have some form of diabetic retinopathy.
According to WHO, 31.7 million people were affected by diabetes in India in the year 2000. This figure is estimated to rise to 79.4 million by 20302)Kaveeshwar SA, Cornwall J. The current state of diabetes mellitus in India. The Australasian Medical Journal. 2014;7(1):45-48. doi:10.4066/AMJ.2013.1979. [PMC free article] [PubMed] [Cross Ref], the largest number in any nation in the world. It is estimated that 15 to 25% of the diabetic population have diabetic retinopathy, and everyone has the potential to develop it over a period of time.
Diabetic Retinopathy is symptomless in its early stage; screening is the only way to identify these patients to prevent them from going blind. Timely treatment can prevent vision loss from diabetic retinopathy. This means that all of the diabetics have to be regularly examined for DR.
What is Diabetic Retinopathy?
Diabetes causes weakening of the blood vessels in the body. The tiny, delicate retinal blood vessels are particularly susceptible. This weakening of retinal blood vessels, accompanied by structural changes in the retina, is termed as diabetic retinopathy. In diabetic retinopathy, the retinal blood vessels may go through a series of changes such as leakage or closure. These changes may progress from one stage to the next 3)Guidelines for the Comprehensive Management of Diabetic Retinopathy in India. A VISION 2020 the Right to Sight India Publication.2008 Jul.
Types of diabetic retinopathy
There are two main categories of diabetic retinopathy,
1. Non-proliferative diabetic retinopathy – when the blood vessels leak and then close.
2. Proliferative diabetic retinopathy – when the new blood vessels grow or proliferate.
Non-proliferative diabetic retinopathy (NDR)
In non-proliferative diabetic retinopathy (also called background retinopathy), the retina may contain capillary leakage, capillary closure, or a combination of the two.
Proliferative diabetic retinopathy (PDR)
Progression to proliferative retinopathy is common with long-standing diabetes. Besides having non-proliferative retinopathy, there may be vessels growing on the retina, and the complications that stem from that condition.
Risk of diabetes mellitus (and therefore diabetic retinopathy)
- A family history of diabetes mellitus.
- Having a high-density lipoprotein (HDL or “good cholesterol”) reading of 35 mg/dL or lower.
- Elevated triglyceride levels (250 mg/dL or higher.
- Having been diagnosed with gestational diabetes or having given birth to a baby weighing 4 kg or higher.
Symptoms of diabetic retinopathy
Diabetic retinopathy often has no early warning signs. There is no pain, and vision may remain unaffected until the disease becomes severe.
If leaking blood vessels cause swelling of the macula (called macular oedema), central vision will become blurred, making it hard to see clearly when driving or reading. Vision may get better or worse during the day, depending on the degree of oedema.
If leaking blood vessels cause bleeding in the eye, symptoms will vary based on how much blood is involved. With relatively limited bleeding, the visual disturbance may appear as spots floating in your visual field. These spots may go away after a few hours.
If bleeding is more severe, vision may suddenly become severely clouded. This can occur overnight during sleep. It may take months for the blood to clear from the eye, or it may not clear at all.
Eye evaluation in diabetic retinopathy
Recording Patient’s History
The onset of the diabetic retinopathy is related to the duration of diabetes mellitus. Hence optometrist or ophthalmologist asks about the duration and family history of diabetes mellitus.
The goal of the eye examination is to evaluate and improve vision, if possible.
Diagnosing diabetic retinopathy
Diagnostic tools such as a slit lamp, ultrasound, and procedures like fluorescein angiography are used, in addition to an ophthalmoscope to assess whether a patient has diabetic retinopathy or other eye problems.
Treating diabetic retinopathy
The laser experience
Laser treatment is usually done in an outpatient setting. The patient is given topical anaesthesia to prevent any discomfort. The patient is positioned before a slit lamp. The ophthalmologist guides the laser beam precisely on the target, with the aid of a slit lamp and a special contact lens. Additional treatment may be required, depending on the patient’s condition. Lasers are also delivered through an indirect ophthalmoscope.
In some patients, there may be bleeding into the vitreous or the vitreous may pull on the retina reducing vision severely. In such instances, a vitrectomy (removal of the vitreous) is the choice of treatment. A vitrectomy is done only after other forms of treatment have been tried and failed to control the progression of disease or progression of visual loss.
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|1.||↑||Wild S, Roglic G, Green A, Sicree R, King H. Global prevalence of diabetes: estimates for the year 2000 and projections for 2030. Diabetes Care. 2004;27(5):1047–1053. doi: 10.2337/diacare.27.5.1047. [PubMed] [CrossRef]|
|2.||↑||Kaveeshwar SA, Cornwall J. The current state of diabetes mellitus in India. The Australasian Medical Journal. 2014;7(1):45-48. doi:10.4066/AMJ.2013.1979. [PMC free article] [PubMed] [Cross Ref]|
|3.||↑||Guidelines for the Comprehensive Management of Diabetic Retinopathy in India. A VISION 2020 the Right to Sight India Publication.2008 Jul|