Abstract
Purpose:
To test prospectively the hypothesis that pars plana vitrectomy alters choroidal thickness and morphology in patients with epiretinal membranes.
Methods:
25 patients with epiretinal membranes were imaged prior to and one week after pars plana vitrectomy using a prototype spectral-domain optical coherence tomography (SD-OCT) system. This system operates at 1060-nm wavelength and enables imaging of both the retina and the choroid over a 36×36° field of view at a speed of 60.000 A-scans/second. The retina, the choroid and both the Haller’s and Sattler’s layer can be automatically segmented, mapped and averaged across the Early Treatment Diabetic Retinopathy Study (ETDRS) grid.
Results:
All 25 patients with epiretinal membranes could be imaged successfully with high resolution and speed. Average subfoveal retinal thickness before and after surgery was 389 μm (range, 193 to 464 μm, SD ± 20 μm) and 339 μm (range, 165 to 436 μm, SD ± 23 μm), respectively. Subfoveal choroidal thickness averaged 327 μm (range, 172 to 441μm, SD ± 22μm) before and 326 μm (range, 170 to 462 μm, SD ± 25μm) after surgery. Neither thickness maps nor averaged thickness values showed statistically significant changes in choroidal thickness after surgery (P>0.05). Haller’s and Sattler’s layer thickness values were also unaltered by pars plana vitrectomy (P>0.05). Qualitative analysis of choroidal thickness maps allowed to evaluate relations between choroidal thickness distribution and vitreoretinal pathology.
Conclusions:
3-dimensional 1060-nm optical coherence tomography enables high resolution imaging of the choroid over a large field of view. Choroidal mapping has added to our understanding of possible correlations between vitreoretinal morphology and choroidal thickness distribution. Choroid thickness and morphology are not altered by pars plana vitrectomy in patients with epiretinal membranes.