Abstract
Purpose: :
To determine how often subclinical diabetic macular edema (DME) increases in thickness to a clinically apparent level of macular edema or is treated during a 2 year period.
Methods: :
Study participants with subclinical DME, defined as absence of edema on biomicroscopic exam of the macular center with a center point thickness on optical coherence tomography (OCT) between 225 and 299 microns, were enrolled among 18 community-based and institutional clinical sites in the Diabetic Retinopathy Clinical Research Network (DRCR.net). Annual follow-up visits 1 and 2 years after enrollment included OCT to identify eyes that had an increase in center point thickness of at least 50 microns and progressed to a thickness of at least 300 microns (OCT progression). Data was collected on any treatment that was delivered for DME during the 2 year study. The primary outcome variable was OCT progression or treatment for DME.
Results: :
Both eyes among 613 study participants (1,226 eyes) were screened to identify and enroll 4.0% of these eyes (49 eligible eyes among 44 study participants). The cumulative probability of meeting the primary outcome was 28% (95% CI: 15%, 39%) by 1 year and 38% (95% CI: 23%, 50%) by 2 years (Figure 1).
Conclusions: :
Subclinical DME appears to be relatively uncommon. With at least annual follow-up, screening for subclinical DME does not seem warranted among most eyes with no evidence of DME on clinical examination. This study suggests that between one-quarter and half of eyes with subclinical DME will progress to more definitive thickening or be judged to need treatment for DME within 2years after its identification.
Keywords: edema • retina • diabetic retinopathy