|
|
|
Vitrectomy for Nontractional Diffuse Diabetic Macular Edema: Study Design and Preliminary Results of the VIDE Study
Diabetic Retinopathy Highlights from Retina/Vitreous Free Papers
| Sunday, November 12, 2006 |
| Barbara Parolini, MD, Giacomo Panozzo, MD
No data is available describing the natural history of diffuse diabetic macular edema (DME), resulting in some questions as to whether the results of the Early Treatment of Diabetic Retinopathy Study (ETDRS) are applicable to this disease state. For example, grid laser photocoagulation is known to be ineffective for diffuse DME.
1-year data from a prospective, randomized clinical trial of nontractional diffuse DME in 107 eyes were reported. Visual acuity (VA), optical coherence tomography (OCT), A1C, creatinemia (a measure of kidney function), and microalbuminuria were tested every 3 months. Eyes with visual acuity <39 ETDRS letters were randomly assigned to pars plana vitrectomy (PPV) or observation.
Contrary to expectation, PPV did not durably improve vision. At 1 year, VA improved by 10 ETDRS letters in 22% of patients treated with PPV and in 19% of deferrals, but VA remained stable in 56% of patients treated with PPV and in 72% of deferrals, while 37% of deferrals with low VA at baseline spontaneously improved. Patients with A1C≥9% had much worse VA and worsened edema than patients with A1C<9%. Edema was stable in both groups. To demonstrate efficacy, it is necessary that patients show improvement exceeding the 15%-20% natural fluctuations in VA. Nontractional diffuse DME is a stable condition related to glycemic control; PPV showed a nonsignificant effect compared to deferral of treatment.
Dr Aiello asked whether diffuse DME was defined by fluorescein angiography. Dr Parolini replied that OCT had been used to diagnose diffuse DME. Dr Aiello stated that thick retinas may respond to treatment differently than leaking retinas. Dr Parolini stated that this study was a follow-on study of vitrectomy, triamcinolone, and laser in eyes with DME. Dr Haller asked whether cataracts affected visual acuity results. Dr Parolini stated they did not. Dr Haller noted that DME is relatively slowly progressive, and that one can wait to treat it. |
|
|
