Relationship between macular hole size and the potential benefit of internal limiting membrane peeling

Microstructural and hemodynamic changes in the fundus after pars plana vitrectomy for different vitreoretinal diseases

BACKGROUND

Pars plana vitrectomy is the standard treatment for several vitreoretinal diseases. Continuous improvements in ophthalmic surgical techniques have led to excellent postoperative recovery of the anatomic structure of the fundus. However, postoperative visual outcomes are not always satisfactory.

METHODS

A literature search of articles published before 31 December 2022 was conducted on PubMed using the following keywords: "diabetic retinopathy," "rhegmatogenous retinal detachment," "idiopathic epiretinal membrane," "idiopathic macular hole," "vitrectomy," "optical coherence tomography," "optical coherence tomography angiography," "microstructure," "microstructural," "hemodynamic," "hemodynamics," and "microcirculation." Additional studies were identified by hand-searching references for relevant studies. Articles were screened for language, repetition, and relevance to the direction of study. Studies with a sample size ≥ 7 and the final follow-up time ≥ 4 weeks after vitrectomy were included in this review. Only articles published in English were included. Articles not related to our topic were excluded. Reviews and single case reports were excluded. We structured this review by disease category. The thickness of the retina and choroid, the area of the foveal avascular zone, the vessel density of the retinal and choroidal capillary plexus, and the potential association of related parameters with postoperative visual outcomes are the main outcome measures of studies included in this review.

RESULTS

A total of 48 studies were included in this review. There were contradictory results regarding the association between postoperative microcirculatory parameters and visual acuity in patients with diabetic macular edema, with some studies concluding that improvement in perimacular microcirculation may be an important factor that affects visual acuity, and others concluded that postoperative improvement in visual acuity was not related to changes in macular blood flow. The results of studies on the relationship between postoperative microstructural and microcirculatory parameters and visual acuity in rhegmatogenous retinal detachment, idiopathic epiretinal membrane, and idiopathic macular hole eyes have been inconsistent. In gas tamponade macula-off rhegmatogenous retinal detachment eyes, postoperative best-corrected visual acuity has been reported to correlate positively with vessel density of deep capillary plexus and negatively with foveal avascular zone area of superficial capillary plexus and deep capillary plexus. In silicone oil tamponade macula-off rhegmatogenous retinal detachment eyes, best-corrected visual acuity has been reported to be positively correlated with the retinal thickness of the parafoveal 3 mm temporal quadrant and positively correlated with the vessel density of the superficial capillary plexus in the foveal, parafoveal, and perifoveal area. In addition, best-corrected visual acuity was worse and associated with reduced thickness of the inner retina, ganglion cell layer, outer plexiform layer, and outer nuclear layer in silicone oil tamponade rhegmatogenous retinal detachment eyes compared to gas tamponade. Postoperative best-corrected visual acuity in idiopathic epiretinal membrane eyes was positively correlated with the foveal avascular zone area but negatively correlated with full retinal thickness and inner retinal thickness in the foveal and parafoveal areas. Improvement in postoperative best-corrected visual acuity in idiopathic macular hole eyes was associated with reduced inner retinal thickness and reduced foveal avascular zone area.

CONCLUSIONS

Microstructural and hemodynamic changes are involved in the recovery process after PPV for different vitreoretinal diseases. The thickness of each retinal layer in different regions of the macula, foveal avascular zone area, and vessel density of different retinal capillary plexuses in different macular regions may be potential prognostic factors for postoperative visual recovery. However, the results of the existing literature are inconsistent and require further study.

[Step-by-step creation of internal limiting membrane fragment for surgical treatment of large idiopathic macular holes]

AIM

to develop a surgical procedure for large idiopathic macular holes (MH) that would involve creation of an original internal limiting membrane (ILM) flap to close the hole with.

MATERIAL AND METHODS

Nineteen patients aged from 59 to 71 years with stage 3 idiopathic MH (by J. Gass) were enrolled. Besides standard ophthalmic examination, spectral optical coherence tomography and microperimetry were performed in all cases. The patients were followed up 2 weeks and then 1 and 3 months after surgery. Surgical procedure was notable for an original ILM flap created in a way that resembles removing petals from a flower. The new method implies that the ILM is peeled off all the way round the MH except for the foveolar area and one particular ILM fragment, which is only partially separated from the retina, from the periphery towards the MH, stopping at some 0.1-0.2 mm from its margin. This last fragment is then inverted to cover the MH.

RESULTS

All surgeries were completed without complications. Visual acuity has gradually increased over the follow-up period in all patients: from 0.1-0.4 to 0.3-0.7 (0.39±0.15 on the average; Sivtsev-Golovin chart). Foveal anatomy has also improved: complete closure of the MH was achieved in 8 patients, partial - in 11. Moreover, all patients demonstrated a shift of the retinal fixation point towards the center of the fovea for 153-369 mm, at that, their fixation has stabilized and absolute central scotomas disappeared.

CONCLUSION

The method developed is a promising treatment for large idiopathic macular holes. Further studies are required.

Cells at the vitreoretinal interface in small full-thickness macular holes

PURPOSE

To report on total number, distribution, and type of cells at the vitreomacular interface in small full-thickness macular holes.

METHODS

Internal limiting membrane specimens were removed from 20 consecutive patients with macular holes <250 μm at times when pharmacologic vitreolysis was not available. Specimens were flat mounted and investigated by phase contrast and interference microscopy and immunocytochemistry. Clinical data were documented including optical coherence tomography analysis using the caliper function. Thirteen antibodies were used for glial cells, hyalocytes, macrophages, retinal pigment epithelial cells, different types of collagen, alpha-smooth muscle actin, and proliferating cells.

RESULTS

There was a positive correlation between macular hole size and cell density at the internal limiting membrane (Spearman's Rho: r = 0.519, P = 0.019). Mostly, single glial cells were found on the internal limiting membrane. In five patients, cell clusters were present. There was a strong immunoreactivity for glial cell markers. Immunoreactivity of hyalocyte markers, alpha-smooth muscle actin, and Ki-67 was found in cell clusters but otherwise sparse.

CONCLUSION

Single cells of glial origin without signs of proliferation or contraction are present in eyes with small full-thickness macular holes. In some eyes, however, clusters of cells can be seen, capable of proliferation and exerting tangential traction. Our findings emphasize the need for better visualization of the vitreoretinal pathology by optical coherence tomography, especially to distinguish between single cells and cell clusters.

Vitreous proteomic analysis of idiopathic epiretinal membranes

To understand the molecular mechanisms of idiopathic epiretinal membranes (iERMs), the vitreous proteomes of patients with iERMs were investigated. The vitreous proteome in patients with iERMs (n = 8) and donor samples (n = 8) was analysed using reversed phase high-performance liquid chromatography (RP-HPLC) coupled with electrospray ionization tandem mass spectrometry (ESI-MS/MS) and GeneGo Metacore™. This research followed the tenets of the Declaration of Helsinki for the use of human subjects. In this current study, 226 significant changes in protein abundance (abundance ratio >2, p < 0.01) were identified in the vitreous proteome of iERM patients compared to normal control vitreous, including 122 proteins that were present at lower levels and 104 proteins that were present at higher levels. In the iERM vitreous samples, complement components, inflammation-related proteins and matrix metalloproteinase were present at higher levels, while normal cytoskeleton proteins were present at lower levels. The top GeneGo pathway was "immune response", the top process network was "inflammation", and the top KEGG pathway was "coagulation cascades". The essential 2-node proteins of the network were estrogen receptor 1 (ESR1) and p300. Among those found at higher levels, ubiquitin-conjugating enzyme E2O (UBE2O) and complement C4A (C4A) were the most abundant proteins, and could be detected in each of the iERM vitreous samples. It can be concluded that iERMs are a complicated pathological process involving inflammation, immune response, and cytoskeleton remolding. UBE2O and C4A may be candidate biomarkers for iERMs.

Oct-based interpretation of the vitreomacular interface and indications for pharmacologic vitreolysis

PURPOSE

To review the role of optical coherence tomography (OCT) in diagnosis and management of vitreomacular disease and the impact of OCT on potential uses of ocriplasmin, a new pharmacologic vitreolysis agent recently approved by the U.S. Food and Drug Administration for the treatment of symptomatic vitreomacular adhesion.

METHODS

Analysis of current literature regarding OCT in diagnosis and management of vitreomacular interface disease.

RESULTS

Posterior vitreous detachment is typically a nonpathologic age-related event. Anomalous posterior vitreous detachment emerges when the vitreous cortex fails to cleanly detach from the macula, optic nerve, or other adherent sites. Focal vitreomacular adhesion is a nonpathologic anatomical designation associated with perifoveal posterior vitreous detachment but normal retinal morphology on OCT. Vitreomacular traction is a pathologic consequence of persistent vitreous attachment with structural disturbance of the macular retina visible on OCT. Full-thickness macular holes are foveal defects continuous through all retinal layers to the retinal pigment epithelium. Vitreomacular traction and macular hole with focal vitreomacular adhesion are indications for pharmacologic vitreolysis.

CONCLUSION

Noninvasive high-resolution OCT imaging has transformed the understanding of vitreomacular interface disease. Careful evaluation of the vitreomacular interface with OCT has increased in importance with the introduction of ocriplasmin for vitreomacular adhesion associated with symptomatic anatomical retinal changes.