Eye Injections Challenge Eye Laser for Diabetic Retinopathy

03 Dec Eye Injections Challenge Eye Laser for Diabetic Retinopathy

There is a small study just published in the journal “Ophthalmology” stating that intraocular injections of Lucentis® were superior to laser photocoagulation for the treatment of diabetic macular edema.  As you read this, don’t forget that the “gold-standard” for treatment of diabetic macular edema is still laser photocoagulation.  These “studies” are very small and not of the caliber needed to change the way we practice, but there is still some merit to the findings.

In this study, 126 patients with diabetic macular edema were split into 3 groups;

1. treated with Lucentis® only
2. treated with laser only
3. treated with laser, then Lucentis

Of the 3 groups, the patients receiving Lucentis®, when compared to the laser only group, had the most improved vision and reduced “thickness” or “swelling” of the macula.  The 3rd group, where laser and Lucentis® were combined, was not significantly better in terms of vision, but the swelling was improved more than laser only.

What Does This Mean? The study indicates that intraocular injections of anti-VEGF therapy are better than laser treatment for diabetic macular edema.  If you watch the internet, many “authorities” will start proclaiming that this is a new, and better, treatment for diabetic macular edema.  But we should be cautious.

First, the best studies require that the “studies” are prospective, randomized and double-blinded.  These studies are prospective (vs. retrospective), randomized to treatments options, and basically, no one knows what treatment is administered, including the doctors and patients.  This helps remove bias and placebo effects.  This also means, in a study like this, “fake” lasers would have been performed along with “sham” injections.  After the study, a code would be cracked to disclose which treatments were given to which patients.

Second, the study is too small and too short to have allow any significant meaning.  “Statistical significance” means that an adequate number of patients were studied such that the results could not have occurred by chance.  I don’t know the actual number of patients needed, but most likely would have involved hundreds instead of tens and would have involved more than one testing center.

We also don’t know if the effects are long-lasting.  We only know there was improvement  in the short period of the study.  Now if the effects are still noted 1-2 years after treatment, for example, then maybe we are on to something.

Last, many aspects of the patient selection and treatment are not standardized.  For example, we don’t know if the patient selection was biased in any way that might favor one treatment over another.  For example, perhaps everyone in one group had better sugar control than the other.

My point is, that studies such as this are suspect due to many shortcomings.  Proper prospective, randomized, double-blinded studies take years to develop, perform and analyze.  The AREDS1 Study is an example.  These studies also take large reserves of cash.

The value of these studies is; however, that if similar “small” studies have similar themes, then these may serve as a nidus to create and form much larger, more formidable studies.  Also, for the clinicians (aka yours truly), it also gives us information about alternative treatments that seem viable.

“Randy”

Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist
Fairfax, Virginia