Optical Coherence Tomography Findings in Diabetic Macular Edema

Diabetic macular edema (DME) is one of the main causes of visual impairment in patients with diabetic retinopathy (Williams et al., 2004). The common diagnostic tools for assessing macular edema are stereo-ophthalmoscopy and fluorescein angiography. Stereoscopic examination of the fundus at the slit-lamp or on stereoscopic color fundus photographs is the standard method, as defined by the Early Treatment Diabetic Retinopathy Study (ETDRS), for evaluating macular thickening and for starting treatment when the clinical significant macular edema level has been reached (ETDRS Report Number 10, 1991). Fluorescein angiography is a complementary method for further detecting vascular leakage. However, these methods are subjective and seem to be insensitive for small changes in retinal thickness (Hee et al., 1995; Shahidi et al., 1991). In 1991 a revolutionary device was introduced in ophthalmology – optical coherence tomography (OCT) – and it dramatically improved the diagnosis of macular pathology (Huang et al., 1991). OCT provides detailed information about retinal microstructure and measures retinal thickness with high precision and reproducibility (Diabetic Retinopathy Clinical Research Network [DRCRN], 2007; Paunescu et al., 2004; Polito et al., 2005; Puliafito et al., 1995). The recently introduced spectral-domain OCT (SD OCT) machines have numerous improvements that enhance our ability to examine retinal microstructure and obtain more reliable measurements.