Vitreous Removal Research Articles

Vitreoschisis-induced vitreous cortex remnants in proliferative vitreoretinopathy: A comprehensive review from basic research to clinical practice.

Proliferative vitreoretinopathy (PVR) significantly impacts the prognosis of rhegmatogenous retinal detachment (RRD), one of the most critical and increasing causes of vision loss in the Western world. Despite advancements in surgical instruments and techniques, the failure rate due to PVR remains substantial, necessitating additional surgeries and often leading to unsatisfactory visual outcomes. This comprehensive review explores the role of vitreoschisis-induced vitreous cortex remnants (VCR) as a critical, previously under-recognised factor contributing to PVR. Vitreoschisis, a phenomenon where the inner lamellae of the posterior vitreous cortex detach while the outermost layers remain attached to the retina, creates VCR that may contain hyalocytes and serve as scaffolds for fibrocellular proliferation. These remnants are difficult to visualise without triamcinolone acetonide (TA) staining, leading to their frequent lack of recognition in clinical practice. Moreover, removing VCR can be challenging and time-consuming, often requiring meticulous surgical techniques to avoid retinal damage and ensure complete elimination. This review consolidates insights from basic research and clinical practice, emphasising the importance of complete vitreous removal and effective VCR detection and removal to mitigate PVR risks. It highlights the histopathological and clinical evidence supporting the hypothesis that VCR, containing hyalocytes, play a pivotal role in preretinal membrane formation. The review also discusses epidemiological data, surgical management strategies and potential future directions, including improved visualisation techniques and the development of new surgical tools and methods. This review aims to improve surgical outcomes and reduce the frequency and burden of RRD-related complications by addressing VCR as a critical factor in PVR.

Investigation of Differences in the Techniques of Experimental Vitreo-retinal Operations on Laboratory Animals

The continuous development of vitreoretinal surgery makes it possible to provide high-tech care to patients with retinal detachment while minimizing intraand postoperative complications. However, their percentage still remains significantly high. This pushes modern ophthalmological science to new research and search for solutions to existing problems. In this task, laboratory animals, on which the latest advances in medicine have been tested for more than 100 years, help like no one else. Unfortunately, the high cost of experiments often repels and/or pushes them back indefinitely. Given the clinical significance of experimental studies of surgical treatment of retinal detachment, as part of the study of the new hydrogel preparation Vitreolon, an analysis was made of methods for removing the vitreous body and their effect on the result of surgical intervention.Purpose: analysis of differences in vitreous removal techniques in laboratory rabbits.Material and methods. The experiment involved 6 rabbits (12 eyes) with induced retinal detachment. In 6 eyes, vitrectomy was performed using a vitreotome, in the others, using a syringe (21G). Subsequently, tamponade of the vitreal cavity was performed with the new hydrogel preparation “Vitreolon”. Ophthalmological examinations were performed on the 1st day, 1st and 2nd week, 1st and 3rd months after surgery. After that, the eyes were enucleated to conduct a morphological study of macropreparations and histological sections of the eyes.Results. According to the results of ophthalmological and laboratory studies, there was no statistically significant difference between the techniques for removing the vitreous body. One rabbit had hypertension and cataracts, which indicates its individual response to surgery. There were no complications that could lead to early termination of the experiment.

SECONDARY GLAUCOMA AFTER VITREORETINAL SURGERY: A RETROSPECTIVE OBSERVASIONAL STUDY

Introduction & ObjectivesSecondary glaucoma is the most common complication after vitreoretinal surgery. Pars PlanaVitrectomy (PPV) is a common surgical procedure aimed at removing vitreous gel and replacing itwith variety of substances denominated tamponades. Vitreous removal and replacement may causeincreased intraocular pressure (IOP). The IOP can be reduced with medical treatment or surgery.The purpose of this study is to describe the characteristics of secondary glaucoma after vitreoretinalsurgery in National Eye Center Cicendo Hospital from January 2019 - December 2020.
 MethodsThis study was a retrospective descriptive study which data were obtained from medical records.Data such as age, gender, vitrectomy tamponades, IOP, onset of glaucoma, and glaucoma treatmentwere collected.
 ResultsOne hundred fifty-three eyes were referred to Glaucoma Unit with increasing IOP after vitreoretinalsurgery. PPV with tamponade was done in 141 eyes (92.16%) and silicone oil (SO) 1000 centistokes(cSt) was the most used tamponade in 101 eyes (66.07%). Secondary glaucoma with open angle wasthe most common type in 124 eyes (81.04%). Secondary glaucoma developed in 4-7 weeks aftersurgery, with the highest IOP recorded at 31-40 mmHg. The IOP decreased after SO evacuation withinitial glaucoma treatment in 121 eyes (79.09%), and glaucoma surgery was performed in 32 eyes(20.91%).
 ConclusionSilicon oil as a tamponade agent after PPV may cause rise IOP in the post-operative period.Evacuation SO needs to be done after retinal adhesion to prevent secondary glaucoma. Therefore,timely detection and anti-glaucoma treatment are important to decreased IOP, or filtration surgerycan be performed.

Injectable alginate-based in situ self-healable transparent hydrogel as a vitreous substitute with a tamponading function

Retinal detachment and other vision-threatening disorders often necessitate vitreous body removal and tamponade injection for retina stabilization. Current clinical tamponades such as silicone oil and expansile gases have drawbacks, including patient discomfort and the need for secondary surgery. We introduce a transparent alginate-phenylboronic acid/polyvinyl alcohol composite hydrogel (TALPPH) as a novel vitreous substitute with tamponading capabilities. In vitro physicochemical, rheological, and optical characterization of in situ self-healable TALPPH was performed, and long-term biocompatibility was assessed in a rabbit model of vitrectomy retinal detachment. In vivo evaluations confirmed TALPPH's ability to inhibit retinal detachment recurrence and preserve rabbit vision without adverse effects. TALPPH's close resemblance to the natural vitreous body suggests potential as a vitreous tamponade substitute for future ophthalmological applications.

Comparison of 27-gauge beveled-tip and 25-gauge flat-tip microincision vitrectomy surgery in the treatment of proliferative diabetic retinopathy: a randomized controlled trial

PurposeTo compare the effectiveness and safety of a 27-gauge (27G) beveled-tip microincision vitrectomy surgery (MIVS) with a 25-gauge (25G) flat-tip MIVS for the treatment of proliferative diabetic retinopathy (PDR).MethodsA prospective, single-masked, randomized, controlled clinical trial included 52 eyes (52 patients) with PDR requiring proliferative membrane removal. They were randomly assigned in a 1:1 ratio to undergo the 27G beveled-tip and or 25G flat-tip MIVS (the 27G group and the 25G group, respectively). During surgery, the productivity of cutting the membrane, the number of vitrectomy probe (VP) exchanges to microforceps, total operation time, vitrectomy time and intraoperative complications were measured. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) and postoperative complications were also assessed to month 6.ResultsForty-seven eyes (47 patients) completed the follow-up, including 25 in the 27G group and 22 in the 25G group. During surgery in the 27G group, cutting the membrane was more efficient (P = 0.001), and the number of VP exchanges to microforceps was lower (P = 0.026). The occurrences of intraoperative hemorrhages and electrocoagulation also decreased significantly (P = 0.004 and P = 0.022). There were no statistical differences in the total operation time or vitrectomy time between the two groups (P = 0.275 and P = 0.372), but the former was slightly lower in the 27G group. Additionally, the 27G group required fewer wound sutures (P = 0.044). All the follow-up results revealed no significant difference between the two groups.ConclusionsCompared with the 25G flat-tip MIVS, the 27G beveled-tip MIVS could be more efficient in removing the proliferative membrane while reducing the occurrence of intraoperative hemorrhages and electrocoagulation using appropriate surgical techniques and instrument parameters. Its vitreous removal performance was not inferior to that of the 25G MIVS and might offer potential advantages in total operation time. In terms of patient outcomes, advanced MIVS demonstrates equal effectiveness and safety to 25G flat-tip MIVS.Trial registrationThe clinical trial has been registered at Clinicaltrials.gov (NCT0544694) on 07/07/2022. And all patients in the article were enrolled after registration.

Vitreous Cortex Remnants Removal With Beveled Vitrectomy Probe During Vitrectomy For Primary Rhegmatogenous Retinal Detachment.

To introduce a new surgical technique with a beveled vitrectomy probe for the removal of peripheral vitreous cortex remnants (VCR) in primary rhegmatogenous retinal detachment (RRD). This study was a retrospective case series. From September 2019 to June 2022, 54 patients with complete or partial posterior vitreous detachment who underwent vitrectomy for primary RRD by a single surgeon were enrolled. After staining the vitreous with triamcinolone acetonide, the presence of VCR was assessed in detail. If VCR were present, the macular VCR were removed using surgical forceps, and then, a free flap of peripheral VCR was used as a handle for removing peripheral VCR using the beveled vitrectomy probe. Of the total patients, the presence of VCR was confirmed in 16 patients (29.6%). There were no intraoperative or postoperative complications, except for retinal redetachment caused by proliferative vitreoretinopathy, that occurred in only one eye (1.9%). Using a beveled vitrectomy probe was a practical solution for removing VCR during RRD vitrectomy because additional instruments were not needed and risk of iatrogenic retinal damage was low.

High-speed Beveled Tip Versus Standard Tip Vitrectomy Probe: A Prospective Randomized Clinical Trial.

To compare the efficiency of the advanced ultravit beveled vitrector probe (10,000 cuts per minute) to the current standard ultravit highspeed (7500 cuts per minute) vitrector probe. A prospective, randomized controlled trial was conducted on patients undergoing routine vitrectomy surgery for epiretinal membrane, full-thickness macular hole, and vitreous opacities. Patients were randomly assigned to undergo PPV with the ultravit highspeed probe (Probe 1) or the advanced ultravit beveled probe (Probe 2). The main outcome measure was time to completion of core vitrectomy and vitreous base shave. Forty patients were enrolled in this study, 20 in each cohort. The average time to completion of core vitrectomy was 10.4 +/- 1.8 min in the Probe 1 cohort compared to 9.7 +/- 2 min in the Probe 2 cohort (P = 0.21). The average time to completion of vitreous base shave was 9.6 +/- 2.7 min in the Probe 1 cohort compared to 9.4 +/- 1.8 min in the Probe 2 cohort (P = 0.39). In the current study, the advanced ultravit beveled probe was noninferior to the ultravit highspeed vitrectomy probe when looking at the time to completion of core vitrectomy and vitreous base shave. The increased cut rate did not affect the efficiency of vitreous removal.

OPTIC DISK PIT STUFFING-TO DO OR NOT TO DO.

Optic disk pit (ODP) is a subset of spectrum of congenital cavitary anomalies. Optic disk pit maculopathy causes progressive visual deterioration and is addressed with pars plana vitrectomy (PPV) with or without ODP stuffing. We report a case of progressive ODP maculopathy who was taken up for 23-G 3-port PPV, with complete vitreous removal and stuffing of the ODP with autologous sclera and sequential analysis of change in the retinal nerve fiber layer (RNFL) thickness. Spectral-domain optical coherence tomography RNFL analysis at 1 and 12 months follow-up postoperatively showed total RNFL thickness decrease from 130 µm to 103 µm respectively. Hemiquadrant analysis showed slight reduction of superior RNFL thickness from 142 µm to 139 µm. However, in the inferior hemiquadrant, the reduction in mean RNFL thickness seems to be significant from 133 µm to 100 µm at 1 and 12 months respectively. Sector-wise analysis of the RNFL thickness showed maximum reduction in the inferotemporal quadrant and other sectors seemed to be relatively preserved corresponding to the area of scleral stuffing. Retrospective or prospective analysis of RNFL health of patients undergoing surgery for ODP-M with stuffing needs to evaluated.

Complications Related to Air and Perfluorocarbon Gas in Vitreoretinal Surgery

Intraocular gases have been used in vitreoretinal surgery for many years. The aim of this study was to evaluate intraoperative and postoperative complications of gas tamponades used in vitreoretinal surgery. Vitreoretinal surgery is known to induce cataract development. With that, cataract progression is related to lens exposure to intraocular gas, the duration of exposure, patient’s age, and the magnitude of vitreous removal. With exposure to intraocular gas, lens becomes strongly refractive, resulting in high miyopia and temporary visual impairment. The other complications of intraocular gases are gas migration, increased intraocular pressure, corneal complications and recurrent retinal detachment. Nevertheless, gases are frequently preferred tamponade agents in vitreoretinal surgery.

The effect of low-frequency ultrasound on the functional and morphological state of the retina of rabbits

Currently, three groups of scientists are developing the introduction and use of lowfrequency ultrasound in retinal and vitreous surgery. There is not enough data and work to study the effects of this type of energy on the functional activity and structural state of the retina. In this regard, we conducted experimental and diagnostic studies using modern and objective methods. The main purpose of this article is analyzing the parameters of the electroretinogram of the rabbit retina and compare it with histological data after removal of the vitreous body using low-frequency ultrasound and mechanical action. Experiments were conducted on Chinchilla rabbits (n=40). In the experimental group (n=20), vitreous removal was performed using low-frequency ultrasound, in the control group (n=20) using a guillotine mechanism. On the 1st, 7th, 14th and 14th days, the parameters of the a- and b-waves of the electroretinogram were recorded. The structural state of the retina was also evaluated on histological sections. On the 1st day after surgery in both study groups there was a decrease in all parameters of the electroretinogram, the evaluation of histological data showed the presence of edema in most layers of the retina. On days 7 and 14, the parameters of the a- and b-waves were restored, but did not return to normal in both groups, a decrease in edema in all layers of the retina was observed on histological preparations. On day 30, the a- and b-wave indicators returned to normal, which indicates the restoration of the functional properties of photoreceptor cells, bipolar and Muller cells in both groups, the retinal layers were clearly visualized on histological sections without signs of edema. Analysis of electroretinogram parameters and histological data showed that the use of low-frequency ultrasound for vitreous removal can be considered safe and promising for further development.

Vitreoretinal surgery in age-related macular degeneration

The structure of the vitreous body, its interaction with the retinal surface and tractive alterations of the vitreoretinal interface may play arole in the pathogenesis and the development of age-related macular degeneration (AMD). From clinical trials it can be concluded that posterior vitreous detachment (PVD) or vitreous removal may protect against the development of neovascular AMD. Vitreomacular adhesions may promote neovascular AMD and may have an impact on the efficacy and frequency of intravitreal vascular endothelial growth factor (VEGF) inhibition. Therefore, vitreomacular surgery may be considered as atreatment option in selected cases. Peeling of epimacular membranes and the internal limiting membrane (ILM) may contribute to stabilizing visual acuity and reducing the treatment burden of current intravitreal pharmacotherapy. At present, surgical interventions in AMD are mainly performed in cases of submacular hemorrhage involving the fovea. The treatment is not standardized and consists of liquefaction of the blood using recombinant tissue plasminogen activator (rTPA) and its pneumatic displacement, potentially combined with VEGF inhibition. Other submacular surgical strategies, such as choroidal neovascularization (CNV) extraction, macular translocation or transplantation of retinal pigment epithelium (RPE) are currently limited to selected cases as asalvage treatment; however, the development of these submacular surgical interventions has formed the basis for new approaches in the treatment of dry and neovascular AMD including submacular or intravitreal gene and stem cell therapy.

Evaluation of the Efficiency and Safety of a 27-Gauge 20,000 Cuts per Minute Vitreous Cutter.

The aim of this study was to evaluate the efficiency and safety of a 27-gauge (G) 20,000 cuts per minute (cpm) vitreous cutter in clinical settings. This was a retrospective and observational study of 40 eyes of 40 patients with idiopathic epiretinal membrane (ERM). Twenty patients (20 eyes) were treated using a 27G 10,000-cpm vitreous cutter (Advanced ULTRAVIT® Probe, Alcon), whereas the remaining 20 patients (20 eyes) were treated using a 27G 20,000-cpm cutter (Hypervit® dual-blade probe, Alcon). All the surgeries were performed by the same surgeon (YM). The time from the start of vitrectomy to the start of ERM peeling was independently measured by two separate examiners using digital videos of each surgery. The average duration of vitrectomy was calculated for each patient. Additionally, the data of the patients in the two groups were extracted from their medical and surgical records and compared. The time from the initiation of vitrectomy until the start of ERM peeling was 184 ± 56.9 and 152 ± 39.5 s for the 10,000-cpm and 20,000-cpm groups, respectively. The duration of vitrectomy was significantly shorter in the 20,000-cpm group than in the 10,000-cpm group (p = 0.041). Postoperative vitreous hemorrhage was observed in one patient in the 10,000-cpm group, whereas no complications were observed in the 20,000-cpm group. In a clinical setting, the 27G 20,000-cpm vitreous cutter may have a higher safety profile and higher efficacy for vitreous removal than that of the 27G 10,000-cpm vitreous cutter.

Autonomous Needle Navigation in Retinal Microsurgery: Evaluation in ex vivo Porcine Eyes.

Important challenges in retinal microsurgery include prolonged operating time, inadequate force feedback, and poor depth perception due to a constrained top-down view of the surgery. The introduction of robot-assisted technology could potentially deal with such challenges and improve the surgeon's performance. Motivated by such challenges, this work develops a strategy for autonomous needle navigation in retinal microsurgery aiming to achieve precise manipulation, reduced end-to-end surgery time, and enhanced safety. This is accomplished through real-time geometry estimation and chance-constrained Model Predictive Control (MPC) resulting in high positional accuracy while keeping scleral forces within a safe level. The robotic system is validated using both open-sky and intact (with lens and partial vitreous removal) ex vivo porcine eyes. The experimental results demonstrate that the generation of safe control trajectories is robust to small motions associated with head drift. The mean navigation time and scleral force for MPC navigation experiments are 7.208 s and 11.97 mN, which can be considered efficient and well within acceptable safe limits. The resulting mean errors along lateral directions of the retina are below 0.06 mm, which is below the typical hand tremor amplitude in retinal microsurgery.

Hypersonic vitrectomy in intraoperative posterior capsular rupture with retained nuclear fragments.

In our report, we present the hypersonic vitrectomy (Vitesse, Bausch and Lomb) being employed for anterior vitreous liquefaction and removal in posterior capsular rupture. The capsular tear with nucleus drop during conventional phacoemulsification was managed by vitrectomy using the hypersonic vitrector after posterior-assisted levitation followed by intraocular lens (IOL) implantation. The minimal cortical and epinuclear lens particles in the anterior chamber and vitreous were also liquefied with a stoke length of 30 to 40 μm and aspirated via the Vitesse vitrectomy system. The same probe performs the vitrectomy and the nucleus removal. The postoperative period was uneventful with clear cornea, normal fundus, and 20/20 best-corrected visual acuity (BCVA). The hypersonic vitrectomy utilizes the ultrasound power of 29.5 kHz and a stoke length of 0 to 60 μm for liquefaction of the vitreous. It can be a safe alternative for vitrectomy and lens removal in a single setting.

Hypersonic vitrectomy: a novel approach to vitreous removal

ABSTRACT Introduction Pars plana vitrectomy is the basis of modern retina surgery, and for the last 40 years, has been achieved using the pneumatic guillotine cutter. Recently, a new vitrectomy design has been developed: the hypersonic vitrector. This technology utilizes ultrasound energy to liquefy vitreous in contrast to the mechanical segmentation of vitreous strands that characterizes pneumatic cutters. Areas covered This review provides a history of the development of vitrectomy and summarizes the critical elements of effective and safe vitrectomy systems. The article will describe the novel hypersonic vitrectomy design, discuss what the initial pre-clinical and in-human studies tell us about its performance compared to standard pneumatic cutters, and considers its role in the future of retina surgery. Expert opinion Hypersonic vitrectomy is the first novel way to segment vitreous since the development of pneumatic guillotine cutters. It has the potential to make vitrectomy more efficient both by reducing operating times as well as enabling surgeons to remove silicone oil and retained lens material all with one instrument. With concurrent advancements in guillotine cutters, hypersonic vitrectomy has a high bar to clear to demonstrate advantages that would result in widespread adoption.

Successful management of a rare case of endogenous endophthalmitis from soft tissue (gluteal) abscess

Endophthalmitis, an ophthalmic emergency carries poor visual prognosis without prompt diagnosis and treatment. Endophthalmitis is often exogenous and rarely endogenous. In this report, we describe a rare case of bacterial endogenous endophthalmitis in an immunocompetent 51-year-old patient due to methicillin-resistant staphylococcus aureus septicemia from a gluteal abscess. Ultrasonography confirmed endogenous endophthalmitis. The patient was treated with immediate intravitreal antibiotic injections, prolonged intravenous antibiotics in association with pars plana vitrectomy, retinal detachment repair and vitreous debris removal. Successful treatment was confirmed with negative blood cultures and a clear vitreous on b-scan ultrasound and fundus photography with improvement of his visual acuity. This case highlights the importance of consideration of rare infectious foci as etiology and prompts treatment for successful resolution of endogenous endophthalmitis.

The Utility of Peripheral Vitrectomy Featuring Scleral Indentation during Scleral Fixation of Intraocular Lenses

Purpose: We evaluated the utility of peripheral vitrectomy featuring scleral indentation; we compared a group who underwent peripheral vitrectomy to a control group for whom vitrectomy was combined with scleral fixation of intraocular lenses (IOLs) in patients exhibiting IOL dislocations.Methods: From January 2018 to December 2020, 20 eyes of patients evidencing IOL dislocations that underwent total vitrectomy, IOL removal, and IOL scleral fixation were evaluated; peripheral vitrectomy with scleral indentation was performed in 10 patients. All operations were performed by the same surgeon. We excluded patients with follow-up periods less than 6 months, those with a history of retinal and/or glaucoma surgery, and patients with retinal abnormalities or glaucoma that might significantly compromise visual acuity. The postoperative best-corrected visual acuity, intraocular pressure, astigmatism changes, and complications were retrieved from the medical records.Results: Six months after surgery, the best corrected visual acuity was 0.95 (the Snellen measure) in the group who underwent peripheral vitrectomy featuring scleral indentation, and 0.60 in the control group (p = 0.029). The total astigmatism values were 0.48 diopter in the former and 2.80 diopter in the latter group; the difference was significant (p < 0.001).Conclusions: In patients with IOL dislocations who underwent vitrectomy combined with IOL scleral fixation, improvements in visual acuity were further enhanced when peripheral vitrectomy was combined with scleral indentation. Complete removal of the peripheral vitreous may stabilize IOL positioning by the remnant vitreous.

Vitreous Opacity Vitrectomy (VOV): Safest Possible Removal of "Floaters".

PurposePrimary opacities that develop in the aging vitreous, commonly termed “floaters,” were once considered merely a nuisance, not justifying any risk of surgical removal. However, vitreoretinal specialists are increasingly recognizing that extensive symptomatic vitreous opacities (SVO) that substantially interfere with activities that critically depend on vision (daily visual activities, DVA), constituting degenerative vitreous syndrome (DVS, see http://floaterstories.com), warrant removal albeit with minimal risk - but no description of how to reduce vitrectomy risks to least possible has been forthcoming. We here describe such a method.Patients and MethodsThe safest possible removal of extensive SVO as described herein was attained by an operation specifically designed for DVS treatment (vitreous opacity vitrectomy, VOV), rather than as only a means of achieving subsequent retinal surgery in the same procedure, as is usually the case. We retrospectively reviewed the outcomes of 100 consecutive VOV operations (in 81 patients, average age 66) performed with ultra-high speed, 27-gauge vitrectomy probes.ResultsAll eyes rapidly achieved continuously clear vision, and no eye developed a clinically significant complication during a year of follow-up. Three small, existent retinal breaks were discovered prior to peripheral vitrectomy and one apparently iatrogenic retinal tear was found at VOV completion, when each was treated. In the eyes that were not pseudophakic, postoperative nuclear sclerosis progression was successfully managed by subsequent cataract extraction.ConclusionThe goals of VOV for DVS are to safely restore continuously clear vision by performing tractionless vitreous removal with respect to the retina and to reduce the lifetime risk of retinal detachment, both by such vitreous removal and by microscopic examination of the peripheral retina under anesthesia (MEPRUA), guiding appropriate prophylactic retinopexy. The otherwise healthy DVS eyes so treated warrant this specific form of vitrectomy, continually focused on achieving least possible risk, to maintain an acceptable risk/benefit ratio.

Spotlight on the Internal Limiting Membrane Technique for Macular Holes: Current Perspectives.

Pars plana vitrectomy has become the standard procedure for primary macular holes (MHs) repair, including the removal of the posterior cortical vitreous, the stripping of eventual epiretinal membranes, and finally an intraocular gas tamponade. During this procedure, peeling the internal limiting membrane (ILM) has been proven to increase closure rates and avoid postoperative reopening in several researches. In fact, even in large MHs more than 400 µm, the advantage of peeling off the ILM was highlighted by better anatomical closure rates. Nevertheless, some authors suggested that ILM peeling is not always essential, because it generates various side effects in retinal structure and function. Furthermore, the ideal amount of ILM peeling and the most effective strategies for removing the ILM are still subject of research. Different surgical modifications have been reported as alternatives to traditional peeling in certain clinical settings, including ILM flaps, ILM scraping, and foveal sparing ILM peeling. As regards large MHs, the introduction of ILM inverted flap appeared as a game changer, offering a significantly higher >90% closure rate when compared to traditional ILM peeling. Modifications to inverted ILM flap procedures have been claimed in recent years, in order to define the best area and direction of ILM peeling and its correlation with functional outcomes. Moreover, several innovations saw the light in the setting of recurrent MHs, such as ILM free flap transposition, inverted ILM flap combined autologous blood clot technique, neurosensory retinal flap, and human amniotic membrane (HAM) plug, claiming higher anatomical success rate also in those complex settings. In conclusion, the aim of this review is to report how the success rate of contemporary macular surgery has grown since the turn of the century, especially for big and chronic MHs, analyzing in which way ILM management became a crucial point of this kind of surgery.

The rabbits retina functional state after exposure to low-frequency ultrasound: electroretinogram indicators analysis

Relevance. Currently, several groups of scientists are working on the implementation of low-frequency ultrasound in surgery of the retina and vitreous body. But there are not enough articles on the study of the functional activity of the retina when exposed to this type of energy. Electrophysiological research methods make it possible to analyze and evaluate the safety, effectiveness of surgical interventions, the effect of new drugs at the level of neurons and visual pathways. The electroretinography method makes it possible to record the bioelectrical activity of retinal neurons during light stimulation during dark and light adaptation. The aim of the study is to carry out a comparative analysis of the aand b-wave indices of the rabbit electroretinogram after experimental removal of the vitreous body using low-frequency ultrasound and mechanical action. Materials and Methods. Experiments were carried out in two groups of Chinchilla rabbits (n = 40). In the experimental group, surgery to remove the vitreous body was performed using low-frequency ultrasound, in the control group a fragmentator with guillotine mechanism was used. Before and after the surgery (1, 7, 14, 30 days) an electroretinogram was recorded, the parameters of the amplitude and latency of the aand b-waves were measured. Results and Discussion. In both groups, a sharp decrease in all parameters was observed on day 1. Later, on the 7th day, the dynamics of the latency of aand b-waves slightly decreased than the preoperative values. On the 14th day after the exposure, the amplitude and peak latency of the aand bwaves in both groups remained at the same level as on the 7th day. On the 30th day, the indicators increased, which indicates the restoration of the functions of photoreceptors and Mueller cells in both groups. There were no statistically significant differences between the study groups at all periods of the study. Conclusion. The use of low-frequency ultrasound for vitreous removal can be considered safe and has prospects for further development and application.