New Treatments for Vision Loss in Diabetes

 

“You should have your eyes checked every year,” is a familiar refrain for the 26 million diabetics living in the United States.   The recommendation for annual dilated eye examinations is so well ingrained in the psyche of diabetic patients that it might as well be printed on the front of their glucose monitors.  What isn’t so well appreciated by diabetics, however, is that a revolution in the management of diabetic vision loss is quietly taking place, promising to disrupt a traditional model that has existed for decades.  Thanks to new diagnostic technology and therapeutics, this revolution has changed the conversation in diabetes from that of slowing vision loss to maximizing vision gain.

Although there are many reasons for vision loss in diabetes, by far the most common cause is diabetic retinopathy, characterized by progressive damage to the retina and its blood supply due to elevated blood glucose.  Almost all diabetics develop diabetic retinopathy, a fact which makes it the largest cause of blindness among working age adults.  Although frequently symptomatic, patients with diabetic retinopathy may accumulate retinal damage for years without noticing a change in their vision.

The traditional approach to diabetic retinopathy began in the 1970s and 80s with the completion of two national clinical trials: the Diabetic Retinopathy Study (DRS) and the Early Treatment of Diabetic Retinopathy Study (ETDRS).  These studies demonstrated the value of using laser light to selectively burn the retina in order to slow the progression of vision loss.  Since that time, millions of diabetics have benefitted from these laser therapies.  However, even with therapy, these patients continue to lose vision.

One explanation for this continued vision loss was the difficulty in diagnosing diabetic retinopathy.  Ophthalmologists have traditionally relied on retinal examination and photography for diagnosis, both of which lack the resolution to adequately measure microscopic changes taking place in the retina.  However, thanks to the recent development of an imaging technology called Optical Coherence Tomography (OCT), doctors have been able to visualize the sequence of diabetic retinal changes at a nearly cellular level.   This OCT imaging allows eye care providers to catch vision threatening retinopathy in earlier stages and monitor it more effectively than ever before.

 

Doctors have also updated their therapeutic armamentarium for dealing with diabetic retinopathy.  Traditional laser treatment causes irreversible burns of the retina, permanently decreasing vision in the area of the burn.  Newer therapies, however, are not destructive to the retina.  One such therapy involves the injection of medications into the eye that reduce retinal swelling and improve central vision.  One such medication, ranubizumab (Lucentis©), is FDA approved specifically for this purpose.  In FDA trials, this drug was shown to improve vision by greater than two lines on the eye chart in patients with swelling of their retina due to diabetic retinopathy.  Other medications, when used off-label, are thought to have similar effects on the retina as well.

Another novel, non-destructive therapy for diabetic retinopathy is MicroPulseTM laser, which uses shortened durations of treatment to stimulate the retina rather than burn it.  Early studies of this technology have demonstrated absence of retinal damage following laser treatment, although improvement in vision has yet to be proven in large clinical trials.

There is a revolution happening in the management of diabetic eye disease.  Thanks to recent advances in technology and treatment, the sobering verdict of diabetic retinopathy has changed.  No longer are patients confined to the certainty of vision loss, but instead have the possibility of better vision today and for years to come.