Treatments for diabetic macular edema

This study compared the different treatments available for diabetic macular edema (DME). It found that VEGF-inhibitors like aflibercept (Eylea) and ranibizumab (Lucentis) were the most effective in improving vision and reducing swelling, but they may have undesirable side effects.

DME is swelling in an area at the back of the eye called the macula. DME can result in visual impairment or loss. DME occurs as a result of diabetic retinopathy. In diabetic retinopathy blood vessels in the retina (part of the eye) become damaged, may become leaky, and may increase in number.

Since the 1980s laser treatments have been used to treat DME. Due to the side effects of laser treatments (such as scar), other therapies have been investigated. More recently, medications that inhibit vascular endothelial growth factor (VEGF), a protein that encourages blood vessel formation, have been found to be useful in treating DME. VEGF-inhibitors include; bevacizumab (Avastin), ranibizumab, and aflibercept. Steroids have also been used in treating DME. Steroids are anti-inflammatory, and inhibit blood vessel formation. Both VEGF-inhibitors and steroids are injected into the back of the eye to treat DME (intravitreal administration) 

This study compared the results of 21 trials examining treatments for DME. 4307 patient eyes were examined. 428 were followed up after 6 months, and 3879 after 12 months. Patients with any type of diabetes were included. At follow-up best visual acuity (BCVA; a measure of vision function), central macular thickness (CMT; swelling), and side effects were examined.

After 6 months ranibizumab improved BCVA the most, followed by bevacizumab. Both were more effective than laser alone. After 12 months aflibercept improved BCVA the most, followed by ranibizumab alone, and ranibizumab in combination with laser.

After 6 months steroids plus laser improved CMT the most, followed by ranibizumab. However, neither improved CMT significantly more than laser alone. After 12 months aflibercept improved CMT the most, followed by ranibizumab alone and ranibizumab plus laser.

The main side effects were increase in pressure in the eye and cataract progression. High pressure in the eye was more common in people treated with steroids plus laser (47.8%) than in those treated with VEGF-inhibitors (4.8%-7.6%). Cataract progression occurred in more people treated with steroids (26.9%) than with VEGF inhibitors (0.5%-8%). High blood pressure, episodes of chest pain (angina), and heart attack were reported in people treated with VEGF-inhibitors. High blood pressure occurred most commonly with aflibercept (12.5%), as did heart attacks (1.9%). Angina occurred the most in people taking ranibizumab (0.8%).

The study concluded that aflibercept was the most effective treatment based on BCVA and CMT changes in 12 months, followed by ranibizumab. The researchers warned that VEGF inhibitors like these should be used carefully because of the risk of side effects like high blood pressure, heart attacks, and angina.

In all of the studies that were examined, people with type 1 diabetes made up less than 20% of participants. Thus the results of this study may not apply equally to all people with diabetes. Furthermore, there are different types of laser treatment used in DME, but the researchers examined these as though they were the same.

Talk to your physician about VEGF-inhibitors if you are diagnosed with DME.