What Is DME?
The macula (the central part of the retina located near the site where the optic nerve connects with the eye) allows you to see fine details clearly. In some people with diabetes, the tiny blood vessels in the retinal tissue become damaged and develop leaks. When this happens, the fluids that leak from the blood vessels cause the macula to swell. This condition is known as macular edema.
Left untreated, macular edema can cause loss of vision, making activities like threading a needle, reading a book, or distinguishing faces difficult or impossible. Vision loss is most pronounced when the center of the macula (fovea) is involved.
DME Standards of Care
For more than a quarter of a century, laser treatment of the retina has been the standard of care for diabetic macular edema involving the fovea. Its effectiveness was proven in a landmark 1985 study, conducted by the Early Treatment Diabetic Retinopathy Study (ETDRS) Research Group, which showed that laser therapy substantially reduced the risk of vision loss and improved the chances for vision improvement in some people with clinically significant DME.
More recently, findings from a 2008 study by the Diabetic Retinopathy Clinical Research Network showed that while laser photocoagulation does improve visual acuity in about 30 percent of people with DME involving the fovea, about 50 percent continued to show central retinal thickening (a sign of macular edema), and approximately 20 percent experienced worsening vision when compared with their baseline measures.
Researchers have continued to investigate other treatments for DME that might produce better results. In that regard, findings from a seminal study led by researchers at Johns Hopkins' Wilmer Eye Institute, were reported in 2010 in Ophthalmology. For this study, investigators followed 691 people (854 eyes) with type 1 or type 2 diabetes and DME involving the fovea. The participants, whose average age was 63, were randomly assigned to receive one of the following treatments:
- sham injections plus prompt laser treatment (293 eyes)
- ranibizumab injections (Lucentis, 0.5 mg) plus prompt laser treatment (187 eyes)
- Lucentis injections (0.5 mg) plus deferred laser treatment (188 eyes)
- corticosteroid injections (triamcinolone, 4 mg) plus prompt laser treatment (186 eyes)
The investigators found that at one year, intravitreal Lucentis with either prompt or deferred laser treatment produced substantial improvements in vision, and the results were significantly better than those seen with laser alone. Approximately half the eyes receiving ranibizumab injections, with either prompt or deferred laser treatment, could read at least two more lines on the ETDRS eye chart or read smaller letters than they could before treatment.
By comparison, about 30 percent of eyes that received laser treatment and sham injections or received laser treatment with triamcinolone injections showed the same degree of improvement.
The results pertaining to vision loss also were impressive for the Lucentis-laser groups. Fewer than 5 percent of eyes in the Lucentis-treated groups experienced a loss of two or more lines on the ETDRS chart, compared with 13 to 14 percent of eyes that received laser treatment with or without triamcinolone.
Complication rates were higher among triamcinolone-treated eyes. Most notably, over two years 59 percent of people in the triamcinolone group who had not previously undergone cataract surgery developed cataracts that required surgery compared with 14 percent of those treated with laser only or laser plus Lucentis. In addition, increased intraocular pressure (a risk factor for glaucoma) was more common in triamcinolone-treated eyes than in Lucentis-treated or laser-only treated eyes: 50 percent, 9 percent, and 11 percent, respectively.
Endophthalmitis, a serious eye infection, though rare, occurred in two eyes treated with Lucentis (less than 1 percent) and two eyes treated with laser only.
What This Study Means
This study is likely to change the way that DME is treated. If you have DME, ask your doctor if this new treatment approach might be appropriate for you.
Eye Injections to Treat DME Related to Diabetic Retinopathy
In February 2015, the U.S. Food and Drug Administration (FDA) approved Lucentis (0.3 mg) to DME. (This drug is also approved to treat age-related macular degeneration and macular edema associated with retinal venous occlusive disease). Common side effects include bleeding of the conjunctiva (tissue that lines the eyelids and covers the white part of the eye), eye pain, floaters, and increased intraocular pressure. Serious side effects include retinal detachment and endophthalmitis (infection within the eyeball).
The FDA expanded the use of aflibercept (Eylea) to treat diabetic retinopathy in patients with diabetic macular edema in March 2015. This medication also is approved to treat wet AMD (age-related macular degeneration) and DME/macular edema secondary to retinal vein occlusions. Eylea is administered by a physician as an eye injection once a month for 5 months and then once every 2 months. Appropriate measures to control blood sugar, blood pressure, and cholesterol levels should be used as well.
Common side effects of Eylea include:
- Bleeding of the conjunctiva
- Eye pain
- Increased intraocular pressure
- Vitreous detachment
- Serious reactions (eye infections [endophthalmitis], retinal detachment)
Updated by Remedy Health Media