Evaluation of Artifacts Associated with Macular Spectral-Domain Optical Coherence Tomography

Correlation between central subfield thickness, visual acuity and structural changes in diabetic macular edema

“…A successful treatment is often anatomically defined as a reduction of intra or subretinal fluids, which results in a reduction of thickness in the ETDRS subfields. Such measures are also important in defining the criteria for inclusion or exclusion in clinical trials, as well as in patient´s care, helping on therapeutic decisions and follow-up of the patient's response (13) . Browning et al suggest the retinal thickness (RT) to be assessed by the CST due to high reproducibility, being based on more scans than the central foveal thickness (CFT), and having higher correlation with other measures of the central macula (14) .…”

“…This statement is corroborated by Alasil et al, who point out that the CFT measure may be more subject to decentralization errors in patients with poor fixation and the CST receives contributions from the parafoveal region, assuming the CST as a better indicator of visual function (12) . Han and Jaffe show that changes in RT within the central 1 mm are more clinically relevant as they relate to changes in the VA, are less susceptible to artifacts and the central thickness measurement can be more reliable than scans performed in peripheral areas (13) . OCT enables to evaluate the edema morphological feature and classifies it in three patterns: cystoid macular edema, serous retinal detachment, and diffuse edema.…”

OCT in the Management of Diabetic Macular Edema

“…An important limitation, however, of the automated quantitative OCT scans is segmentation breakdown in which the inner or outer retinal boundary is incorrectly identified resulting in abnormal retinal thickness measurements. This has been found to occur in up to 37 % of scans of the central 1 mm in both the Cirrus and the Spectralis OCT machines [11]. Thus, careful evaluation of the OCT data is important in preventing these errors from making diagnostic mistakes in patients with DME.…”

“…b DME with disruption of the ELM and IS-OS ellipsoid layer laser and anti-VEGF therapy. The presence of vitreoretinal traction and/or an epiretinal membrane, associated with a loss of the foveal depression and the presence of a taut, thickened posterior hyaloid, has been associated with edema that may be refractory to medical therapy and may respond better to a pars plana vitrectomy with peeling of the posterior hyaloid [11].…”

Neovascular Age-Related Macular Degeneration

“…This grid gives an overview of the current state of edema in each of the subfi elds, most importantly in the foveal central millimeter subfi eld. All devices have the possibility to correct the foveal position and the automatically segmented thickness values to avoid errors by technical artifacts that are very common in nAMD because of bad patient fi xation and various morphologic patterns [ 10 ]. In general, thickening and thinning retina are activity signs -thickening indicates exudation and thinning progressive retinal cell loss in atrophy and fi brosis.…”