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To compare macular pigment optical density (MPOD) in healthy eyes versus eyes affected by primary epiretinal membrane (ERM) in different stages and to assess the relation between MPOD and optical coherence tomography findings.Prospective cross-sectional study of 62 eyes of 62 patients affected by unilateral primary ERM. Contralateral healthy eyes from the same patients were used as a control group. Main outcome measures were MPOD, ERM stage, central foveal thickness (CFT), outer nuclear layer thickness (ONLT), integrity of outer retinal bands, and presence of central bouquet abnormalities.In the study group, mean CFT was 444 ± 75 μm and mean ONLT was 245 ± 40 μm, whereas in the control group, mean CFT was 230 ± 21 μm and mean ONLT was 102 ± 14 μm (P0.001). Mean MPOD was 0.86 ± 0.07 in eyes with ERM and 0.48 ± 0.09 in contralateral healthy eyes (P0.001). Macular pigment optical density was associated with CFT (P = 0.006) and ONLT (P0.001), whereas no significant associations were observed between MPOD and outer retinal bands integrity (P = 0.14) and central bouquet abnormalities (P = 0.08).Macular pigment optical density increased in eyes affected by primary ERM proportionally to CFT and, especially, ONLT. Probably, centripetal forces exerted by ERM contraction on the retinal surface lead to a progressive foveal packing of foveal Müller cells.

Proliferative vitreoretinopathy (PVR) is an abnormal intraocular scarring process that can complicate cases of rhegmatogenous retinal detachment (RRD). Although previous studies have examined the relevance of microRNAs (miRNAs) in ophthalmic diseases, only a few studies have evaluated the expression profiles of microRNAs in subretinal fluid. We hypothesized that the expression profiles of specific miRNAs may change in response to RRD, in the subretinal fluid that is directly in contact with photoreceptors and the retinal pigment epithelium (RPE). We looked for a potential correlation between the expression of specific miRNAs in eyes with RRD and known clinical risk factors of PVR. A total of 24 patients (59 ± 11 years) who underwent scleral buckling procedure were enrolled in this prospective study. Twenty-four undiluted subretinal fluid samples were collected, RNA was isolated and qRT-PCR was performed to analyze the expression of 12 miRNAs. We found the existence of a positive association between the expression of miR-21 (p = 0.017, r = 0.515) and miR-34 (p = 0.030, r = 0.624) and the duration of symptoms related to retinal detachment. Moreover, the expression of miR-146a tended to decrease in patients who developed PVR. Subretinal fluid constitutes an intriguing biological matrix to evaluate the role of miRNAs leading to the development of PVR.