Abstract
Purpose: :
Epiretinal membranes can lead to distortion of the macular region and to vision loss. Surgical traction relief through vitrectomy and membrane peeling can induce restructuring of the retinal layers and functional improvement. The aim of this study was to measure the morphological changes in the neurosensory and photoreceptor layers after epiretinal membrane peeling.
Methods: :
Thirty eyes of 30 consecutive patients were examined before and at days 1, 4 and 7 and at 1, 3, 6, 12 and 24 months following standard three-port 20G vitrectomy and membrane-peeling. Parameters were best-corrected visual acuity (BCVA) and high-resolution optical coherence tomography (HR-OCT) using Cirrus HD-OCT (Carl Zeiss Meditec). Standard central retinal thickness (CRT) of the built-in software was recorded at each visit. Furthermore, the distance between the internal limiting membrane (ILM) and the external limiting membrane (ELM) as well as the distance between the ELM and the retinal pigment epithelium (RPE) was measured manually at two defined sites: at the foveola and at the area of the strongest retinal traction. These values were then analyzed over time and correlated to BCVA.
Results: :
Preoperative BCVA was 20/50, decreased to 20/66 during the first postoperative week and increased steadily until 20/28 at 24 months. Standard CRT decreased from 483 um to 466 at day 1 post-OP and further down to 389, 388, 371 um at months 6, 12 and 24, respectively. After two years, the distance from ELM to RPE as an indirect marker of photoreceptor integrity increased from 83.9 to 88.3 um at the previous locus of most intensetraction and from 89.1 to 95.6 um at the foveola. The release of traction could also be observed in the layer between ILM and ELM: thickness decreased from 431 to 315 at previous traction and from 415 um to 273 um at the foveola.
Conclusions: :
Manual measurement of retinal layers following the release of vitreomacular traction provides valuable insight into the recovery process of retinal tissue. The observed changes may indicate a recovery of the photoreceptor layer integrity, which is accompanied by the increase of BCVA.
Keywords: macula/fovea • vitreoretinal surgery • imaging/image analysis: clinical