Folding the internal limiting membrane flap under perfluorocarbon liquid in large, chronic and myopic macular holes.

PURPOSE: The purpose of the present paper is to describe a surgical technique aimed at creating multiple layers of Internal Limiting Membrane (ILM) using Perfluorocarbon Liquid (PFCL) in order to favour the closure of large, chronic and myopic Macular Holes (MH). METHODS: Thirty patients belonging to 3 subgroups: large (> 500 µm), chronic (> 12 months) and myopic (> - 9 diopters), MHs, underwent surgery and completed 6 months follow-up. The ILM was engaged and peeled 360° around the MH, hinged to the rim and folded over the hole. A PFCL bubble spanning the vascular arcades was then injected and the ILM is grasped repeatedly to fold the distal edge towards the MH centre, creating multiple ILM layers over the MH. RESULTS: MH closed in 26/30 cases (86.6%) with no significant difference among subgroups. Vision improved 2.57 ± 1.56 Snellen lines from LogMAR 1.50 ± 1.19 to 1.19 ± 1.32 (p < 0.01). Ellipsoid Zone (EZ) interruption width reduced from 1129 ± 439 µm to 258 ± 507 µm (p < 0.001) and correlated to pattern of MH closure, post-BCVA and line improvement (p < 0.001 in all cases). DISCUSSION: The use PFCL allows multiple ILM layers and resulted in a high closure rate. Pattern of MH closure differs from those previously described leaving a plug of ILM tissue that interrupts retinal architecture often only in the inner layers. PFCL gravity and hydrophobicity displace aqueous while the intensely polar opposite faces of the ILM attract each other. The folded ILM plugs MH and bridges the gap and may help glial cell proliferation and migration.

Does the Bursa Pre-Macularis protect the fovea from shear stress? A possible mechanical role.

Purpose of present study is to evaluate whether the Pre-Macular Bursa (PMB) modifies Wall Shear Stress (WSS) at the retinal surface during saccadic movements. We created a mathematical model consisting of 25,000 grid cells and simulated a horizontal saccade spanning 50° in 0.17s, both in absence and in presence of the PMB. Wall Shear Stress SS was computed throughout the retinal surface and the posterior pole was divided into 3 Zones comprising 400 nodes each: Zone 1 (radius 3.5 mm; 0°-17°) corresponding to the PMB area; Zone 2 (concentric annular area 5 mm in radius; 22°) and Zone 3 (concentric annular area 5.5 mm; 28°). The PMB reduced WSS significantly at the macula and increased it in the immediate surroundings. Average WSS in Zone 1 was 1.53 ±â€¯1.01 (max 4.23 Pa) with PMB Vs 6.94 ±â€¯9.23 (max 35.83 Pa) without. Zone 2 WSS was 9.39 ±â€¯10.33 (max 48.36 Pa) with PMB Vs 6.95 ±â€¯9.40 (max 38.60 Pa) without Zone 3 WSS was 8.41 ±â€¯10.03 (max 43.16 Pa) with PMB Vs 6.88 ±â€¯9.42 (max 39.43 Pa) without (p < 0.001 in all cases). The PMB significantly reduces WSS over the retinal surface underlying the bursa region; conversely, WSS slightly increases it in the immediate neighboring areas.

Macular hole closure patterns associated with different internal limiting membrane flap techniques.

PURPOSE: To compare the anatomic and functional outcome of two variants of the inverted internal limiting membrane (I-ILM) flap technique for idiopathic macular holes (IMH) larger than 400 µm. METHODS: Twenty-seven consecutive patients undergoing PPV for IMH were randomly assigned to different variants of I-ILM technique: the Cover group included 14 patients in which the I-ILM was folded upside-down over the MH as a single layer while the Fill group enrolled 13 patients in which the I-ILM was folded within the MH in multiple layers. RESULTS: MH closed in 12/14 Cover and in 13/13 Fill eyes (84.6 vs. 100%, p = 0.14; n.s.). Vision at 1 month was Snellen 0.44 ± 0.17 vs. 0.28 ± 0.21 (p = 0.05) and 0.48 ± 0.20 vs. 0.37 ± 0.25 (n.s.) at 3 months. IS/OS line interruption width was 463 ± 385 vs. 602 ± 210 µm, respectively, at 1 month (n.s.) and 602 ± 210 vs. 563 ± 209 µm at 3 months (n.s.). The Cover group showed outer retina cystic changes more often (p < 0.01). MH over 700 µm closed in 0/2 and in 2/2 cases, respectively, in the Cover and Fill groups (0.045). CONCLUSIONS: Cover and Fill I-ILM techniques allowed similar closure rates and post-operative vision at 3 months. The Cover group showed better anatomical restoration and vision at 1 month while the Fill technique might be more efficient in closing larger MHs.

Human Vitreous Collagen Fragments Dimension As a Function of Vitrectomy Cut Rate.

Purpose: To study the dimensions and distribution of human vitreous collagen type II fragments collected after vitrectomy performed at varying cut rates and to evaluate if increasing the cut rate produces smaller collagen fragments, thus reducing retinal traction and/or viscosity. Methods: Fluid was collected during core vitrectomies performed for macular surgery at cut rates from 1000 to 16,000 cuts per minute (CPM) and immediately refrigerated. Protein fractions were separated by molecular weight (MW; >100 kDa, 50-100 kDa, 50-30 kDa, 30-10 kDa, and <10 kDa) through centrifugal filters. The Human Collagen II ELISA Kit colorimetric assay was then used to measure the COL2A1 in unfiltered and filtered samples. Results: Vitreous samples collected after vitrectomy performed at 16,000 CPM contained a higher concentration of protein with MW over 100 kDa than at any other cutting frequency (P < 0.01). No significant differences were found in fractions collected with a MW between 50 and 100 kDa. Collagen type II fragments over 100 kDa were significantly more represented than smaller fragments at each cut rate. The proportion of smaller (50-100 kDa) collagen fragments compared with those over 100 kDa was higher at 2000 CPM than at higher cut rates. Conclusions: Vitreous samples collected at different cut rates do not contain a significantly different proportion of collagen type II fragments of the tested MW. The extreme variability of vitreous flow through the cutter port may explain the uncertain predictability of collagen fragment MWs. Translational Relevance: Increasing the cut rate does not produce vitreous fragments of proportionally smaller dimension. It is necessary to achieve an invariant instantaneous flow through the cutter port in order to decrease retinal traction during vitrectomy.

Autologous internal limiting membrane transplant for recurrent idiopathic macular holes.

PURPOSE: To report a series of recurrent idiopathic macular holes treated by means of a free autologous internal limiting membrane flap and compare visual and anatomic results to a control group undergoing further internal limiting membrane peeling and novel gas tamponade. METHODS: Retrospective surgical series of 15 consecutive patients receiving autologous internal limiting membrane flap compared to 14 patients operated on for internal limiting membrane peeling enlargement. Autologous internal limiting membrane flap was created after brilliant blue G staining, internal limiting membrane lifting, perfluorocarbon bubble injection and creation of a wide internal limiting membrane free flap translocated underneath perfluorocarbon liquid, to the macular hole bed. Both groups were tamponated with 20% SF6 and positioned face down for 4 h a day for 3 days. RESULTS: Macular hole closed in 14/15 (93.3%) patients of the autologous internal limiting membrane group and 9/14 (64.2%) controls (p < 0.05). Visual acuity increased from 0.05 ± 0.03 to 0.23 ± 0.13 Snellen in the autologous internal limiting membrane group and from 0.05 ± 0.03 to 0.14 ± 0.10 Snellen of controls (p < 0.05 for both). Vision of the autologous internal limiting membrane group improved more than controls at 1 month (p = 0.043) and 3 months (p = 0.045). Inner segment/outer segment interruption at 3 months was smaller in the autologous internal limiting membrane group than controls, reducing from 1230 ± 288 µm at baseline to 611 ± 245 and 547 ± 204 µm at 3 months versus 1196 ± 362, 745 ± 222 and 705 ± 223 µm, respectively (p < 0.05). CONCLUSION: Autologous internal limiting membrane flap can effectively close recurrent idiopathic macular holes with a higher closure rate, smaller residual inner segment/outer segment line interruption and higher visual acuity at 3 months than previous standard of care.

Autologous internal limiting membrane flap for retinal detachment due to posterior retinal tears over choroidal atrophy in highly myopic eyes.

PURPOSE: To review a series of highly myopic eyes with retinal detachment undergoing pars plana vitrectomy with autologous internal limiting membrane (ILM) flap placed over posterior retinal breaks located in areas of choroidal atrophy. METHODS: Retrospective review of 13 consecutive patients receiving pars plana vitrectomy with ILM flap over causative breaks, compared with 19 controls receiving the same surgery with ILM peeling but no ILM flap. Main outcome measures included anatomical success rate, visual acuity, number of surgeries and the rate of silicone oil removal. RESULTS: Patients in the ILM group required 2.08±0.37 interventions versus 2.58±0.75 in the control group (p=0.037). One (1/13; 7.6%) patient in the ILM group required additional unplanned surgery versus 8/19 (42.10%) in the control group (p=0.038). Final anatomical success rate defined as attached retina after silicone oil (SiO) removal was 13/13 in the I-ILM group and 14/19 (73.6%) in the control group (p=0.052). No patients (0/13) in the I-ILM group retained SiO at the end of follow-up versus 4/19 (21.1%) patients in the control group (p=0.061). Best-corrected visual acuity at the end of follow-up was logMAR 0.65±0.36 (20/91 Snellen) in the ILM group and logMAR 0.89±0.44 (20/158 Snellen) in the control group (p=0.20). CONCLUSION: Autologous ILM may help seal posterior retinal breaks and improve the surgical prognosis of retinal detachment due to breaks located over areas of choroidal atrophy within the myopic staphyloma.