(RxWiki News) For some with diabetes, changes in blood sugar can distort vision because of leaking blood vessels in the eyes. An eye medication has shown long-term promise in treating this visual impairment.
Diabetes patients can develop a condition called diabetic macular edema (DME) in which fluid leaks into the macula, the center of the retina that allows for sharp, straight-forward vision. The fluid swells the macula, which then blurs vision.
In 2012, the Food and Drug Administration approved ranibizumab (brand name Lucentis) to treat this condition. A new study has shown that the medication can effectively improve and maintain vision over the course of three years, and that as vision improves, fewer injections of ranibizumab are needed.
"Tell a doctor if your vision blurs, especially if you have diabetes."
Dr. Ursula Schmidt-Erfurth, from the Department of Ophthalmology at the Medical University Vienna, and colleagues followed up on a year-long study of diabetes patients with DME designed to evaluate the effects of ranibizumab.
Dr. Schmidt-Erfurth and her team tracked patients for an additional two years. These patients had received either ranibizumab injections alone, ranibizumab injections and laser treatment or laser treatment alone.
Of the 303 subjects who finished the initial 12-month investigation, 208 completed the extension study. The researchers determined ranibizumab dosing at their own discretion.
Over the two-year extension study, Dr. Schmidt-Erfurth and colleagues noted an overall maintenance of best corrected visual acuity (BCVA), which is best distance vision with eyeglasses or contact lenses.
Laser therapy can be used to reduce moderate vision loss in patients with clinically significant macular edema. The authors of this study noted that prior laser-treated patients, who were eligible to receive ranibizumab treatment in this extension study, showed a progressive improvement of BCVA over three years.
When the retina swells from DME, it does not function as well and vision declines. The retina is the light-sensitive tissue at the back of the inner eye. It converts images to electric signals and sends them via the optic nerve to the brain.
Ranibizumab has been shown to decrease retinal thickness. Patients treated with ranibizumab in the core and extension studies had an average reduction of central retinal subfield thickness (CRST) of 127.8 μm (micrometers) at the one year mark and 142.1 μm at three years. Patients in the ranibizumab/laser group had a mean CRST reduction of 139.7 μm at one year and 145.9 μm at year three.
In this extension study, the average number of ranibizumab injections (0.5 mg dose) declined as sight improved among patients. From day one to month 11, patients received an average of about 7.5 injections. In the final year, the average number of injections was 2.5 for the laser and medication group and 2.9 for the medication alone group.
Most people who have diabetes have nothing more than minor eye disorders, according to the American Diabetes Association. Still, about 3.9 million adults diagnosed with diabetes reported trouble with their vision in 2010.
“Ranibizumab was effective in improving and maintaining BCVA and CRST outcomes with a progressively declining number of injections over three years of individualized dosing,” the authors wrote. “Ranibizumab was generally well tolerated with no new safety concerns over three years.”
The FDA has reported that the most common side effects reported in patients treated with this medication include bleeding of the conjunctiva (the tissue that lines the inside of the eyelids and covers the white part of the eye), eye pain, floaters and increased pressure inside the eye (intraocular pressure).
The FDA previously approved ranibizumab to treat wet (neovascular) age-related macular degeneration (AMD), a condition in which abnormal blood vessels grow and leak fluid into the macula.
This study was published online in February in Ophthalmology and sponsored by Novartis Pharma AG, Switzerland, which markets Lucentis.