Lloyd P Aiello, MD, PhD
The staggering number of patients with diabetes implies that every ophthalmologist in the US would need to see 1 patient every 24 seconds every hour of every day of every year to keep up with all the patients who need eye examinations and treatment. Thus, anything that can be done to reduce this workload is helpful.
Good diagnostic procedures are the foundation for appropriate and timely treatment selection. Diagnosis begins with a careful patient history and the careful administration of a standardized test for visual acuity. Optical coherence tomography (OCT) is an exciting, rapidly evolving imaging modality for macular edema. OCT quantifies retinal thickness, assesses vitreomacular interface abnormalities, and evaluates changes in retinal thickness over time. OCT images can be obtained in a matter of seconds, shortening exam times. However, these anatomic measurements are not a surrogate for measuring visual acuity.
Evidence-based diagnostic and therapeutic standards for macular edema do exist, but new treatments for macular edema are in clinical trials. These new treatments fall into 2 categories: laser treatments and pharmacologic treatments.
Focal/grid laser photocoagulation, the standard treatment for diabetic macular edema (DME) requires a large number of laser burns and is time-consuming to perform. The new pattern scanning laser (Pascal laser) permits multiple laser burns to be delivered with a single press of the footswitch in a pattern selected by the ophthalmologist. The Diabetic Retinopathy Clinical Network compared mild macular grid laser to modified Early Treatment Diabetic Retinopathy Study focal/grid laser and found that mild macular grid laser is not an effective treatment for DME.
Pharmacologic treatments currently in clinical trials for macular edema include anti-VEGF agents, antisignaling agents, and steroids. Pegaptanib, ranibizumab, and bevacizumab are examples of anti-VEGF agents. Recently, it has been shown that ranibizumab can reduce retinal thickness and increase visual acuity in macular edema. Ruboxistaurin is an example of an antisignaling agent. Dr Aiello was an investigator in Phase III studies of this drug that have been published recently (PKC-DRS2 Group. Effect of ruboxistaurin on visual loss in patients with diabetic retinopathy. Ophthalmology. 2006 Sep 19.). Triamcinolone, fluocinolone, and dexamethasone are examples of steroid treatments for macular edema. Dr Aiello recommended that unproven new treatments should be used with caution pending definitive pivotal trial results.
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