Tomographic Structural Changes of Retinal Layers after Internal Limiting Membrane Peeling for Macular Hole Surgery

Abstract

Purpose: To highlight tomographic structural changes of retinal layers after internal limiting membrane (ILM) peeling in macular hole surgery. Methods: Nonrandomized prospective, interventional study in 38 eyes (34 patients) subjected to pars plana vitrectomy and ILM peeling for idiopathic macular hole. Retinal layers were assessed in nasal and temporal regions before and 6 months after surgery using spectral domain optical coherence tomography. Results: Total retinal thickness increased in the nasal region and decreased in the temporal region. The retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) showed thinning on both nasal and temporal sides of the fovea. The thickness of the outer plexiform layer (OPL) increased. The outer nuclear layer (ONL) and outer retinal layers (ORL) increased in thickness after surgery in both nasal and temporal regions. Conclusion: ILM peeling is associated with important alterations in the inner retinal layer architecture, with thinning of the RNFL-GCL-IPL complex and thickening of OPL, ONL, and ORL. These structural alterations can help explain functional outcome and could give indications regarding the extent of ILM peeling, even though peeling seems important for higher rate of hole closure.

Inner Retinal Layer and Outer Retinal Layer Findings after Macular Hole Surgery Assessed by means of Optical Coherence Tomography

“…Faria and associates found that 6 months after ILM peeling, the RNFL, GCL, and IPL had a decreased thickness in both the nasal (−12.8 μ m) and the temporal regions (−29.6 μ m). As a possible explanation, the authors hypothesized that, after ILM peeling, inner retinal cells were particularly affected by local inflammation, microcirculatory ischemia, and stretching effects [27]. The same group found a shortening of papillofoveal distance and thickening in the outer retinal layers (ORLs) in both nasal and temporal regions during the follow-up [28].…”

Tomographic Structural Changes of the Inner Retina after Internal Limiting Membrane Peeling for Idiopathic Epiretinal Membrane

“…Reductions in RNFL, GCL, IPL, and OPL were observed in both the nasal and temporal subfields, while INL and ONL showed thickening of the nasal subfield and thinning of the temporal subfield. These results might have been caused by release of traction from the ERM after removal and induction of nasal displacement to the inner retina from ILM peeling [10][11][12][13][14][15][16][17].…”

“…The INL and ONL showed nasal retinal thickening and temporal thinning after surgery, which suggests that the effect of nasal displacement in these layers might be greater than that of retinal thinning after ERM removal. Postoperative nasal parafoveal thickening and temporal thinning of the inner retina have been reported in eyes undergoing ILM peeling for ERM [10][11][12][13][14] and macular holes [15][16][17]. The mechanisms responsible for these processes have not been fully identified, but foveal displacement toward the optic disc and shortening of the papillofoveal distance might be responsible [15].…”

“…However, there are concerns that ILM peeling may cause retinal changes, including postoperative swelling of the arcuate retinal nerve fiber layer (RNFL) [4], inner retinal dimples [5], and reduction of the temporal peripapillary RNFL thickness [6][7][8][9]. Thinning of the retina in the temporal subfield and thickening of the nasal subfield of the macula due to nasal displacement of the retina have also been reported [10][11][12][13][14][15][16][17]. These processes have been suggested as secondary changes resulting from axonal transport and contractility alterations in the RNFL due to apoptotic and atrophic degeneration in the peripapillary area [18]; however, the mechanism and related factors for these processes are not definitively known.…”

Multifocal Electroretinography in Assessment of Macular Function after Internal Limiting Membrane Peeling in Macular Hole Surgery

“…Nerve fibers are joined and fixed at the lamina crivosa, and after ILM peeling, a dissociated optic nerve layer has been referred by Tadayoni et al [7]. Also, nasal displacement and contraction of this neural layer and ganglion cell axon allow the underlying macular tissue to react with the alteration of cytoarchitecture of external retinal layers [8]. All these structural alterations may have consequences on postoperative macular function.…”