Assessment of the Significance of Cystic Changes After Epiretinal Membrane Surgery With Internal Limiting Membrane Removal

Abstract

Purpose To assess the prevalence and significance of cystic changes after internal limiting membrane (ILM) peeling during epiretinal membrane (ERM) surgery. Methods A retrospective review was performed on 64 patients who underwent pars plana vitrectomy (PPV) with membranectomy for idiopathic ERM between January 2010 and January 2012 by a single physician. PPV alone (Group 1, n=32) or in combination with phacoemulsification (Group 2, n=32) were performed. Peeling of the ERM was assisted by triamcinolone, and ILM was peeled up to the vascular arcades with the aid of brilliant blue dye. Results In Group 1, BCVA in logMAR (Snellen) improved from 0.53±0.29 (20/68) at baseline to 0.23±0.22 (20/34) at 6-month follow-up (p<0.001). Two cases (6.3%) developed new cystic changes within the inner nuclear layer (INL); however, there was no significant difference in BCVA at 6-months (p=0.475). In Group 2, BCVA improved from 0.41±0.17 (20/51) at baseline to 0.18±0.15 (20/30) at 6-months (p<0.001). Eight cases (25%) developed new INL cystic changes; however, there was no significant difference in BCVA at 6-months (p=0.894). Conclusions Development of new INL cystic changes following ERM surgery may be a frequent finding, but in contrast to cystoid macular edema, does not appear to affect visual recovery and should be observed. The combination of PPV with cataract extraction may increase the risk of INL cystic changes.

Perioperative intraretinal fluid observed using optical coherence tomography in the epiretinal membrane

“…The incidence rate of postoperative IRF including persistent preoperative IRF was 29.1% at 6 months, and the incidence rate of new IRF was 41% (49 out of 119) in the eyes without preoperative IRF. Previous studies have reported widely varying postoperative IRF incidence rates, 13 to 64% [5][6][7], and new IRF incidence rates, 1 to 15.6% [5,7,8]. It is likely that the highest incidence rate [6] would represent thickening of the macula by both mechanical deformation and presence of fluid, as postoperative macular edema was assessed based on macular thickness measured by OCT and not based on the presence of IRF.…”

“…Frisina et al [5] reported an incidence rate of about 10% for postoperative CME and new CME, as assessed by six radial scans (not a volume scan). Dolz-Marco et al [7] compared the incidence rates of new IRF depending on whether combined phacoemulsification was performed or not, using macular cube scans, and reported the incidence to be 6.3% in the vitrectomy only group and 25% in the combined surgery group. In the current study, when patients were similarly divided into two subgroups, similar incidence rates, i.e., 6.9% among patients who underwent vitrectomy alone and 37.3% among those who underwent combined surgery, were observed.…”

“…Previous studies have reported the incidence of macular edema after PPV. Particularly for ERM, the incidence rates of macular edema after PPV varied between 13 and 64% [5][6][7]. Previously, macular edema was synonymous with macular thickening detected by ophthalmoscopic examinations.…”

“…The presence of IRF was associated with a delay in postoperative visual improvement [5,8]. Additionally, cystoid changes were also commonly observed before ERM surgery [5,7]. In these cases, persistent preoperative IRF would introduce a bias in interpreting the impacts of postoperative IRF, which includes both persistent IRF and newly developed IRF.…”

Characteristics of Epiretinal Membrane Remnant Edge by Optical Coherence Tomography After Pars Plana Vitrectomy

“…Previous studies have demonstrated an association between the external limiting membrane, and ellipsoid zone with the post-operative visual acuity outcomes and metamorphosia. 12-13 Post operative complications of ERM removal such as swelling of the arcuate nerve fiber layer, cystoid macular edema, delayed new-onset inner nuclear layer cystic changes, and extrafoveal macular holes after ERM surgery have been reported and can now be followed by OCT. 14, 15,16 …”