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Novel microscope-integrated OCT now allows targeted intraoperative high-resolution real-time imaging. In comparison to conventional surgical microscopes, intraoperative real-time OCT visualisation of retinal layers and vitreous body provides valuable information for surgical decision-making. In addition, simultaneous OCT imaging of retinal structures displayed within the funduscopic view through the eye-piece of the microscope allows direct guidance of instrument-tissue interaction and surgical manoeuvres. As a result, targeted iOCT imaging enables enhanced precision and the development of real-time guided surgical techniques at micron level., Competing Interests: Berater- und Referententätigkeit: Carl Zeiss Meditec., (Thieme. All rights reserved.)

Purpose: To evaluate the different mechanisms of retinal detachment recurrence after retinectomy for rhegmatogenous retinal detachment (RD) complicated by proliferative vitreoretinopathy (PVR) and to study its outcome and prognosis., Methods: Retrospective, multicenter study conducted between January 2009 and November 2016. Retrospective review of 56 patients with recurrent RD (RRD) after a first relaxing retinectomy., Results: The secondary retinal attachment rate was 58.9% (33/56 cases). The various mechanisms of RRD were mainly related to PVR (52/56 cases: 93%). This PVR was anterior in 10 cases (21%), posterior in 31 cases (60%), and combined anterior and posterior in 11 cases (21%). The RRD mechanism was not PVR in 4 of the 56 cases. Some of the RRD mechanisms were specific to retinectomy: fibrosis of the edge of the retinectomy (26 cases: 46.4%), beyond-the-edge proliferation (8 cases: 14.3%), and severe inferior retinal folding (2 cases: 3.6%). In the 2 cases of severe inferior retinal folding, the retina could not be reattached. The anatomical outcome and the mechanism of RRD (anterior PVR, posterior PVR, or combined anterior and posterior PVR) were not correlated (P = 0.12). Visual acuity was significantly better only in patients with complete secondary success, that is, having an attached retina after silicone oil removal: mean preoperative visual acuity was 2.01 logarithm of the minimum angle of resolution versus 1.01 logarithm of the minimum angle of resolution postoperatively (P = 0.019)., Conclusion: Proliferative vitreoretinopathy caused most of the recurrences, and the anatomical outcome did not depend on the type of PVR involved. Only complete secondary success (attached retina after silicone oil removal) was accompanied by visual acuity improvement.

Purpose: To compare intraocular pressure, anterior segment optical coherence tomography, and ultrasound biomicroscopy parameters over 3 months after panretinal photocoagulation (PRP) for proliferative diabetic retinopathy after 1 of 2 sittings by conventional laser (half PRP) and a single sitting of Pattern Scan Laser (PASCAL) PRP., Methods: This was a prospective, randomized, interventional study. All tests were performed at baseline, and at 1, 6, and 24 hours, and 1, 4, 8, and 12 weeks after PRP., Results: The intraocular pressure at 1 hour and 6 hours after PRP was significantly raised in both groups. Mean intraocular pressure was 21.17 ± 4.01 mmHg after PASCAL and 17.48 ± 3 mmHg after conventional laser at 1 hour, P < 0.001. On anterior segment optical coherence tomography, conventional laser PRP caused a more significant narrowing of angle-opening distance (AOD750) and trabecular-iris space area (TISA 500), P = 0.03 and 0.04, respectively, on Day 1. Ultrasound biomicroscopy showed a significantly narrow angle in both groups on Day 1. A significant increase in ciliary body thickness was observed in both groups, with 57.1% of PASCAL and 100% of conventionally treated eyes showing ciliary effusion on Day 1 that decreased but persisted for the next 3 months., Conclusion: Performing PRP in sittings, prescribing previous glaucoma medications in patients at risk, and recording intraocular pressure an hour after the PRP could decrease complications.

We used magnetic resonance imaging (MRI) to assess how a patient's posture affects intraocular gas changes and whether the postoperative prone position is required after pars plana vitrectomy (PPV) with gas tamponade for rhegmatogenous retinal detachments (RRDs). Eight patients with RRDs who underwent PPV combined with cataract surgery with gas tamponade were prospectively included. They underwent MRI examination both in the prone and supine positions. We separated the retina into four parts: superior-posterior, superior-anterior, inferior-posterior, and inferior-anterior. We then calculated the gas contact rate as (the length of the retina contacting the gas in each retinal part) divided by (the length of each retinal part) × 100% in both the prone and supine positions. The mean gas contact rate of the superior-anterior part of the retina was significantly higher (P = 0.006) in the supine position than in the prone position. The mean gas contact rate of the inferior-anterior part of the retina was also significantly higher (P = 0.0004) in the supine position than in the prone position. We believe that if all retinal breaks were located anterior to the equator, the supine position may provide better tamponade gas coverage for the breaks than the prone position. Although potential postoperative complications caused by the supine position require careful attention, our result may shorten the duration of postoperative prone position and may decrease the patients' discomfort after PPV with gas tamponade for RRDs.

Purpose: To determine whether there were any adverse consequences from seeing vitreoretinal surgery patients on the second rather than the first postoperative day., Methods: A retrospective review of vitreoretinal surgical patients from a single surgeon seen on the second, but not the first day after surgery. Preoperative, intraoperative, and postoperative findings were recorded with attention to adverse or safety events., Results: One hundred thirty-four patients were identified, representing a variety of vitreoretinal pathology and surgical procedures. All patients received a technician phone call on the first postoperative day inquiring about pain and vision. Six patients had an intraocular pressure over 30 on the second postoperative day, all managed medically. Only one patient was seen on the first postoperative day because of pain and elevated pressure. There were no cases of endophthalmitis., Conclusion: Postoperative vitreoretinal surgical patients can reasonably be seen on the second postoperative day, when logistics dictate, allowing them to be seen by their operative surgeon in a more convenient location.

Objective To evaluate the efficacy of maximal pneumatic retinopexy (PR) and subretinal fluid (SRF) drainage combined with scleral buckling (SB) in the treatment of complicated rhegmatogenous retinal detachment (RRD). Methods Patients with RRD who underwent maximal PR and SRF drainage combined with SB from June 2007 to June 2012 were included in this multicenter retrospective study. The outcome measures were the primary and final operation success rates and best-corrected visual acuity (BCVA). Results In total, 159 consecutive patients were included. The mean follow-up period was 13.76 ± 1.97 months. Primary operation success was achieved in 146/159 (91.82%) eyes. After salvage management, the final reattachment rate increased to 98.11%. All eyes had improved BCVA, with 62/159 (38.99%) attaining BCVA of ≥20/40. Conclusions Maximal PR and SRF drainage combined with SB achieved satisfactory anatomical and visual recovery in relatively complicated cases of RRD. The decreased need for vitrectomy makes this surgical approach more widely available.

Purpose: Preliminary assessment of a new prototype ultrasound-based hypersonic vitrector (HV) by qualitatively examining the histopathological changes in the retina and vitreous body after pars plana vitrectomy (PPV) and its ability to fragment vitreous collagen., Methods: Fourteen porcine cadaveric eyes, 20 eyes in live swine and six human cadaveric eyes underwent PPV using the HV or a pneumatic guillotine vitrector (GV). An additional 4 porcine crystalline lenses were touched with either the HV or GV for 1 minute. Following PPV, human vitreous was removed and processed for electron microscopy (EM). Eyes and lenses were fixed and sectioned for light microscopy (LM)., Results: There were no macroscopic retinal or optic nerve defects associated with either HV or GV PPVs. Cadaveric retinal specimens showed separation of the inner limiting membrane (ILM) and vacuolization and fragmentation at the nerve fiber layer (NFL) and the ganglion cell layer (GCL). ILM fragmentation and separation were found after PPV in live swine with both vitrectors. Small disruptions of the posterior capsule or structural lens defects were found after HV touch. The EM analysis revealed more fragmentation of human vitreous collagen fibrils after HV compared to GV PPV., Conclusions: LM and EM analysis of retina, vitreous, and crystalline lens after PPV showed similar morphological changes using the HV or the GV. Vitreous fragmentation appeared more effective with the HV. Overall this study suggests that the HV may be a promising new technology. More work is needed to quantitatively assess its safety and efficacy.

Purpose: The aim of this study was to evaluate the relationship between oxidative stress and human vitreous degeneration, using the presence of an evident posterior vitreous detachment (PVD) as a clinical sign and thiobarbituric acid-reactive substances (TBARS) and nitrite as oxidative biomarkers., Methods: We collected 42 vitreous samples from patients undergoing pars plana vitrectomy for two groups of vitreoretinal diseases (macular holes and epimacular membranes). TBARS and nitrite were assessed spectrophotometrically and compared to the presence of an evident PVD, considering other clinical features potentially related to the oxidative stress in the vitreous: diabetes, plasma fibrinogen, type of intraocular lens (IOL), and the vitreoretinal disease requiring the surgery., Results: Vitreous TBARS levels were significantly higher in patients with artificial IOLs compared to those with natural lenses and cataracts (1.39±0.64 versus 0.75±0.45; p=0.003). Furthermore, patients with PVD had a significant increase in vitreous TBARS compared to those without PVD (1.45±0.54 versus 0.53±0.38; p=0.001). The plasma fibrinogen levels explained 17% of the TBARS variance, with a significant correlation between these two markers (p=0.011). No significant differences were observed when nitrites were used as biomarkers., Conclusions: Current IOLs, even with ultraviolet (UV) absorber, do not ensure the same photoprotection offered by natural lenses affected by corticonuclear cataracts. Furthermore, we observed a relevant correlation between the increased presence of peroxidation products in the vitreous and an evident PVD, but the nature of this relationship requires further study.

Surgical emphysema is defined as gas or air trapped in the subcutaneous tissue plane. Here, we report a rare case of bilateral periorbital and cervicofacial subcutaneous emphysema following a vitreoretinal surgery for inadvertent globe perforation during the administration of peribulbar anesthesia. This condition, although self-resolving when restricted to the subcutaneous plane has the potential to spread into deeper tissue planes such as the retropharyngeal space. The presence of crepitus helps to distinguish it from angioneurotic edema. Ophthalmologists must be sensitive to the fact that surgical emphysema can be a very rare, but possible complication of an intraocular surgery following globe perforation.

The authors propose an effective technique to isolate whole, intact vitreous core and cortex from post mortem enucleated porcine eyes. While previous studies have shown the results of such dissections, the detailed steps have not been described, precluding researchers outside the field from replicating their methods. Other studies harvest vitreous either through aspiration, which does not maintain the vitreous structure anatomy, or through partial dissection, which only isolates the vitreous core. The proposed method isolates the whole vitreous body, with the vitreous core and cortex intact, while maintaining vitreous anatomy and structural integrity. In this method, a full thickness scleral flap in an enucleated porcine eye is first created and through this, the choroid tissue can be separated from the sclera. The scleral flap is then expanded and the choroid is completely separated from the sclera. Finally the choroid-retina tissue is peeled off the vitreous to leave an isolated intact vitreous body. The proposed vitreous dissection technique can be used to study physical properties of the vitreous humor. In particular, this method has significance for experimental studies involving drug delivery, vitreo-retinal oxygen transport, and intraocular convection.

The number of elderly patients using anticoagulant and antiplatelet treatment in prevention of thromboembolism has significantly increased in recent years. It was believed for many years that those patients may be at higher risk for hemorhages during ocular surgery. Different strategies were proposed to prevent these complications, including discontinuation of anticoagulants, dose reduction, or substitution with low molecular weight heparin. The objective of this work was to evaluate the results of studies presenting the results of vitreoretinal surgeries in patients continuing antiplatelet and/or anticoagulant treatment. We performed a PubMed search of possible intraoperative and postoperative hemorrhages in patients receiving anticoagulant and/or antiplatelet therapy during vitreoretinal surgery in 2007-2014. In most of the studies reviewed there was no substantial increase in intraoperative and postoperative hemorrhages risks during vitreoretinal surgery. However, in some studies, a substantially increased risk has been identified. We conclude that the available data is insufficient to decide whether to continue or discontinue anticoagulant and/or antiplatelet therapy during vitreoretinal surgery and we recommend an individualized approach in consultation with the patient's medical doctors and anesthesiologists.

Silicone oil has been the only long-term vitreous substitute used in the treatment of retinal detachment since 1962 by Cibis. Nevertheless, its effects on retinal vascular morphology and oxygen supply to the retina are ambiguous in current research. We previously invented a foldable capsular vitreous body (FCVB) to use as a new vitreous substitute in the treatment of severe retinal detachment, but its effects on the retinal vessel were unknown. Therefore, in this study, a standard three-port pars plana vitrectomy (PPV) was performed on the right eye of each rabbit and then silicone oil and FCVB were injected into the vitreous cavity as vitreous substitutes. After 180 days of retention, the retinal vascular morphology did not display any distinct abnormalities, and hypoxia-induced factor-1alpha (HIF-1α) and vascular endothelial growth factor (VEGF) did not vary markedly during the observation period in silicone oil tamponade- and FCVB-implanted eyes. This study may suggest that silicone oil and FCVB tamponade in rabbit eyes did not cause retinal vascular pathologic changes or retinal hypoxia for 180 days.

Purpose: To compare the laser spot quality between the conventional slit lamp pattern laser (PASCAL) and the navigated pattern laser (NAVILAS) for panretinal photocoagulation (PRP)., Methods: Prospective randomized interventional trial of 73 eyes (51 patients) with high-risk proliferative diabetic retinopathy. Eyes underwent PRP using 30-ms pulse duration with either PASCAL (16 eyes) or NAVILAS laser (21 eyes), or 100-ms pulse duration with either PASCAL (16 eyes) or NAVILAS laser (20 eyes). Fundus color images of all quadrants were taken 5 minutes after treatment. Laser burn size (major and minor diameter and area) and ellipticity (ratio of minor to major axis) were analyzed across the retina. Treatment time and pain were compared between both groups., Results: The burn size variation in navigated laser 30 ms, 100 ms, and conventional pattern 30 ms and single-spot 100 ms laser was 22%, 24%, 21%, and 35%, respectively. The variation of the laser burn area near the arcade for NAVILAS and for PASCAL was 29% and 22%, respectively (P < 0.01). Closer to the equator, burns from the NAVILAS showed even smaller variation of 15% compared with 25% with PASCAL (P < 0.005). Laser spots from PASCAL exhibited an increasing elliptical shape toward the periphery, whereas NAVILAS laser spots tended to be more uniform all over the retina. Average treatment duration and pain experience was less with navigated laser compared with pattern laser (P ≤ 0.05)., Conclusions: Navigated laser treatment achieves more uniform laser burns with less pain during shorter treatment duration in comparison with conventional pattern laser., (Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.)

Hydrogels may be the ideal vitreous substitutes due to their wonderful physical features and biocompatibility. However, their drawbacks, short residence time, and biodegradation in vivo, have led to the fact that none of them have been approved for clinical use. In this study, we developed a novel approach of using a foldable capsular vitreous body (FCVB) injected with polyvinylalcohol (PVA) hydrogel as a vitreous substitute for long-term tamponade. The 3% PVA hydrogel that was cross-linked by gamma irradiation showed good rheological and physical properties and had no toxicity in vitro. After 180 days retention, the 3% PVA hydrogel inside FCVB remained transparent and showed good viscoelasticity without biodegradation and showed good biocompatibility and retina support. This new approach may develop into a valuable tool to improve the stability performance of PVA hydrogel as a vitreous substitute and to extend the application function of FCVB for long-term implantation in vitreous cavity.

Purpose: We aim to understand how mechanical causation influences retinal detachment and reattachment processes. In particular, myopes suffer retinal detachment more frequently than emmetropes, and following a retinal detachment, scleral buckling promotes retinal reattachment. We test the hypothesis that stresses arising from saccadic eye rotations are involved in the processes, and that the alteration in the stress due to the change in the vitreous chamber geometry is sufficient to explain the phenomena., Methods: The vitreous chamber of the eye has an approximately spherical shape and it is filled with vitreous humor. We developed a mathematical model, treating the vitreous chamber in emmetropic and myopic eyes as a spheroid and in eyes subjected to scleral buckling as a sphere with a circumferential indentation. We assume that the eye performs prescribed small-amplitude, periodic, torsional rotations and we solve semi-analytically for the fluid pressure, velocity, and stress distributions., Results: The shape of the vitreous chamber has a large effect on the retinal stress. The vitreous and the retina of a highly myopic eye continuously experience shear stresses significantly higher than those of an emmetropic eye. An eye fitted with a scleral buckle experiences large stress levels localized around the buckle., Conclusions: Our results provide a mechanical explanation for the more frequent occurrence of posterior vitreous detachment and retinal detachment in myopic eyes. To understand how the stress distribution in a buckled eye facilitates reattachment, an additional model of the details of the reattachment process should be coupled to this model.

Purpose: Dexmedetomidine is a highly selective alpha-2 adrenergic agonist that has a sedative effect and has been shown to reduce anesthetic requirements. It also has a sympatholytic effect, which may prove useful when used to blunt the sympathetic surge during intubation and extubation. However, its effects on intraocular pressure, hemodynamic stability, attenuation of extubation response, and emergence agitation remain unclear for pediatric patients undergoing vitreoretinal surgery. We focused on these effects in this study., Methods: Sixty ASA I-II patients undergoing vitreoretinal surgery, were anesthetized with sevoflurane 1-2% end-tidal concentration in oxygen supplemented by remifentanil 0.2 μg/kg/min. Intraocular pressure was measured after inhalation of sevoflurane (IOP(Baseline)) and 10 min after intravenous administration of dexmedetomidine 0.5 μg/kg or normal saline (IOP(10min)), after induction of anesthesia. Blood pressure and heart rate were recorded every 5 min during surgery. The incidence and severity of coughing and emergence agitation and untoward airway events after extubation, for example breath holding, laryngospasm, bronchospasm, and oxygen desaturation, were assessed. Extubation time and emergence time were also documented., Results: There was no significant difference in intraocular pressure at the two time points between the groups (p > 0.05). In both groups mean arterial pressure and heart rate decreased from baseline after anesthetic induction (p < 0.05). The increase from intraoperative values in mean arterial pressure and heart rate associated with extubation was diminished in the dexmedetomidine group compared with the control group (p < 0.05). Coughing after extubation was less common (10 vs. 21) and less severe (3 moderate and 7 minimal; vs. 2 severe, 7 moderate and 12 minimal) in the dexmedetomidine group than in the control group (p < 0.05). There were no significant differences between the groups in time to emergence or extubation (p > 0.05). The dexmedetomidine group had a lower incidence of emergence agitation than the control group (10 vs. 43.3%, p < 0.05). The incidence of breath holding, laryngospasm, bronchospasm and oxygen desaturation was not significantly different between the groups (p > 0.05)., Conclusions: Dexmedetomidine 0.5 µg/kg had no effect on intraoperative hemodynamics or intraocular pressure, but attenuated the hemodynamic response to extubation and diminished emergence agitation in pediatric patients undergoing vitreoretinal surgery.

Passengers with intraocular gas are at risk of profound visual loss when exposed to reduced absolute pressure within the cabin of a typical commercial airliner. Information provided on the websites of the world's 10 largest airlines offer a considerable range of opinion as to when it might be safe to fly after gas injection. Physicians responsible for clearing pseassengers as 'fit to fly' should be aware modern retinal surgical techniques increasingly employ long-acting gases as vitreous substitutes. The kinetics of long-acting intraocular gases must be considered when deciding how long after surgery it is safe to travel. It is standard practice to advise passengers not to fly in aircraft until the gas is fully resorbed. To achieve this, it may be necessary to delay travel for approximately 2 wk after intraocular injection of sulfur hexafluoride (SF6) and for 6 wk after injection of perfluoropropane (C3F8).

While the mouse retina has emerged as an important genetic model for inherited retinal disease, the mouse vitreous remains to be explored. The vitreous is a highly aqueous extracellular matrix overlying the retina where intraocular as well as extraocular proteins accumulate during disease.(1-3) Abnormal interactions between vitreous and retina underlie several diseases such as retinal detachment, proliferative diabetic retinopathy, uveitis, and proliferative vitreoretinopathy.(1,4) The relative mouse vitreous volume is significantly smaller than the human vitreous (Figure 1), since the mouse lens occupies nearly 75% of its eye.(5) This has made biochemical studies of mouse vitreous challenging. In this video article, we present a technique to dissect and isolate the mouse vitreous from the retina, which will allow use of transgenic mouse models to more clearly define the role of this extracellular matrix in the development of vitreoretinal diseases.

Diabetic retinopathy remains a major cause of worldwide preventable blindness. The vitreo-retinal interface plays a critical role in the pathogenesis of diabetic retinopathy. The term pharmacologic vitreolysis refers to the use of enzymes to liquefy the vitreous gel, and to induce posterior vitreous detachment (PVD). Intravitreal ovine hyaluronidase injection was effective in clearing vitreous hemorrhage. Several human case series demonstrated that intravitreal injection of autologous plasmin enzyme was a safe and effective adjunct to vitreous surgery for the treatment of diabetic macular edema and proliferative diabetic retinopathy. Recently, it was shown that intravitreal injection of plasmin enzyme without the performance of vitrectomy induced complete PVD and reduced macular thickening due to refractory diabetic macular edema.

Vitreous constitutes about 80% of the volume of the human eye. It is an extended extracellular matrix that is composed of collagen, hyaluronan, and other extracellular matrix molecules, but mostly water. In both health as well as disease, especially diabetic retinopathy (DR), special attention should be drawn to the posterior vitreous cortex and its relation to the retinal surface. The important role of vitreous in the pathogenesis of proliferative DR has already been demonstrated by several experimental and clinical studies. Thus, vitreo-retinal separation by pharmacologic vitreolysis and/or removal by surgical means are appropriate approaches to interrupt the pathogenic contribution of vitreous and prevent progression of diabetic retinopathy to more advanced stages. This review describes various aspects of the molecular morphology and structural anatomy of vitreous and the vitreo-retinal interface, as well as the role of vitreous in the pathophysiology of DR. Lastly, this treatise provides a critical analysis of novel vitreous modulators for pharmacologic vitreolysis in the treatment of DR. Microplasmin is currently the most promising approach to treat vitreoretinal traction by pharmacologic vitreolysis.

Purpose: To quantify the extent of cellular proliferation and immunohistochemically characterize the proliferating cell types in epiretinal membranes (ERMS) from four different conditions: proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy, post-retinal detachment, and idiopathic ERM., Methods: Forty-six ERMs were removed from patients undergoing vitrectomy and immediately fixed in paraformaldehyde. The membranes were processed whole and immunolabeled with either anti-MIB-1 or anti-SP6 to detect the K(i)-67 protein in proliferating cells, in combination with anti-glial fibrillary acidic protein or anti-vimentin to identify glia, anti-ezrin to identify retinal pigment epithelial cells, Ricinus communis to identify immune cells, and Hoechst to label nuclei. Digital images were collected using a laser scanning confocal microscope. The cell types were identified, their combined proliferative indices were tabulated as the average number of anti-K(i)-67-positive cells/mm(2) of tissue, and the number of dividing cells was related to the specific ocular condition and estimated disease duration., Results: ERMs of all four types were shown to be highly cellular and contained proliferating cells identified as glia, retinal pigment epithelium, and of immune origin. In general, membranes identified as PVR had many more K(i)-67-positive cells in comparison to those in the other three categories, with the average number of K(i)-67-positive cells identified per mm(2) of tissue being 20.9 for proliferative diabetic retinopathy, 138.3 for PVR, 12.2 for post-retinal detachment, and 19.3 for idiopathic ERM. While all membrane types had dividing cells, their number was a relatively small fraction of the total number of cells present., Conclusions: The four ERM types studied demonstrated different cell types actively dividing at the time of removal, confirming that proliferation is a common event and does continue over many months. The low number of dividing cells at the time of removal in comparison to the total number of cells present, however, is an indicator that proliferation alone may not be responsible for the problems observed with the ERMs. Treatment strategies may need to take into consideration the timing of drug administration, as well as the contractile and possibly the inflammatory characteristics of the membranes to prevent the ensuing effects on the retina., (© 2011 Molecular Vision)

Background: To determine the therapeutic and diagnostic value of vitreoretinal surgery in various types of severe viral retinitis and endogenous endophthalmitis., Material/methods: Pars plana vitrectomy with silicon-oil tamponade was performed on 12 eyes (12 patients) with severe viral retinitis and endogenous endophthalmitis. The mean age of the patients was 35.2 years (range, 18-56 years). Investigations consisted of chest radiography, RT 23, serology (for toxoplasmosis, cytomegalovirus, herpes simplex virus, and human immunodeficiency virus), and routine blood tests and urinalysis. Examination of vitreous samples consisted of polymerase chain reaction for cytomegalovirus, herpes simplex virus, and Mycobacterium tuberculosis, and cultures for fungi and bacteria. The results were analyzed 7 days and 6 months after surgery., Results: Analysis of vitreous samples showed cytomegalovirus in 3 patients, herpes simplex virus in 2, tuberculosis in 2, and Candida albicans in 5. All patients had improvement in visual acuity and severity of clinical signs seven days after surgery and in 10 cases after long-term follow-up. Final visual acuity was compromised by chronic macular edema, postinflammatory macular scarring, optic atrophy, subcapsular cataract formation, and capsular opacification after cataract surgery., Conclusions: Modern laboratory tests are useful for quick and accurate diagnosis of atypical cases of severe infectious posterior uveitis. Early pars plana vitrectomy with silicon oil tamponade is valuable in diagnosing and treating severe infectious posterior uveitis and endophthalmitis.

Accidental laser exposure to the eyes may result in serious visual impairment due to retina degeneration. Currently limited treatment is available for laser eye injury. In the current study, we investigated the therapeutic potential of bone marrow-derived stem cells (BMSCs) for laser-induced retinal trauma. Lineage negative bone marrow cells (Lin(-) BMCs) were labelled with quantum dots (Qdots) to track the cells in vivo. Lin(-) BMCs survived well after intravitreal injection. In vivo bromodeoxyuridine (BrdU) labelling showed these cells continued to proliferate and integrate into injured retinas. Furthermore, they expressed markers that distinguished retinal pigment epithelium (RPE), endothelium, pericytes and photoreceptors. Our results suggest that BMSCs participate in the repair of retinal lesions by differentiating into retinal cells. Intravitreal transplantation of BMSCs is a potential treatment for laser-induced retinal trauma., (Published by Elsevier Ltd.)

Purpose: To investigate whether pan-retinal photocoagulation (PRP) affects vitreous levels of cytokines and macular thickening in patients with high-risk proliferative diabetic retinopathy (PDR)., Methods: Fourteen patients with bilateral high-risk PDR--which requires pars plana vitrectomy (PPV)--but without a history of retinal photocoagulation participated in this study. Before PPV, one eye received PRP, and the other eye did not. The concentrations of cytokines of vascular endothelial growth factor (VEGF), stromal derived factor-1 (SDF-1), interleukin-6 (IL-6) and regulated upon activation, normal T-cell expressed and secreted (RANTES) were measured in each vitreous sample obtained at PPV. Macular thickness obtained by optical coherence tomography was also monitored during clinical course., Results: After the PRP, macular thickness in PRP-pretreated eye showed temporal increase. Vitreous levels of IL-6 and RANTES in PRP pre-treated eye were significantly higher than levels in control eyes (p = 0.013, p = 0.033). Although macular thickness in control was correlated to vitreous levels of VEGF and IL-6 (p = 0.022, p = 0.003), that in PRP-pretreated eye was closely correlated to IL-6 and RANTES (p = 0.002, p = 0.011). After the PPV, macular thickness in both eye groups improved, and there was no significant difference between both eye groups 3 months after the PPV., Conclusions: In patients with high-risk PDR, PRP cause temporal worsening of macular edema linked with pro-inflammatory cytokines of IL-6 and RANTES, but not with VEGF and SDF-1. Thus, PRP-induced macular edema was caused by inflammation, while visual prognosis after PPV was not influenced by pretreatment of PRP.

Purpose: This paper describes the development and evaluation of a parallel prototype robot for vitreoretinal surgery where physiological hand tremor limits performance., Methods: The manipulator was specifically designed to meet requirements such as size, precision, and sterilization; this has six-degree-of-freedom parallel architecture and provides positioning accuracy with micrometer resolution within the eye. The manipulator is controlled by an operator with a "master manipulator" consisting of multiple joints., Results: Results of the in vitro experiments revealed that when compared to the manual procedure, a higher stability and accuracy of tool positioning could be achieved using the prototype robot., Conclusions: This microsurgical system that we have developed has superior operability as compared to traditional manual procedure and has sufficient potential to be used clinically for vitreoretinal surgery.

Background: The vitreous body is implicated in the etiology and pathology of a variety of retinal conditions. Many such conditions are treated surgically to remove the posterior vitreous from the inner limiting lamina (ILL) of the retina, and there is current interest in the adjunct use of enzymes for this purpose. To evaluate the efficacy of these agents in future preclinical studies, improved preservation and assessment methods were developed to establish a baseline histological profile of the vitreous and retina of the rabbit, to identify and distinguish artifactual vitreoretinal separation from authentic posterior vitreous detachment, and to preserve structural integrity while maintaining antigenicity for immunohistochemical analysis., Methods: Two pigmented rabbits each underwent perfusion with one of three fixatives, either: (1) 10% neutral buffered formalin + cetylpyridinium chloride (NBF/CPC), (2) acid-ethanolic formalin + CPC (AEF/CPC), or (3) formaldehyde-glutaraldehyde + CPC (FG/CPC). An eye fixed in NBF/CPC by immersion, from an additional rabbit, was also included for comparison. Eyes were processed whole through paraffin infiltration. Treatments were assessed by immunohistochemical labeling for retinal and cortical vitreous (CV) markers., Results: In contrast to immersion fixation, perfusion with either NBF/CPC or AEF/CPC maintained vitreous adherence to the ILL during histological processing. NBF/CPC proved best for highlighting intralaminar structure and for labeling type II collagen in the CV, particularly with antigen retrieval. AEF/CPC caused condensation of fibrillar elements in the CV. Collagen XVIII in the ILL was observed with AEF/CPC exclusively. Only retinal vessels near the optic nerve head were labeled for type IV collagen. The labeling of glia was useful for distinguishing between cellular and extracellular elements. GF/CPC hindered detection of collagen II and disrupted posterior segment structure. Expression of type II collagen extended from the ONH directly to CV affiliated with the central canal of Cloquet, a feature characteristic of rabbit eyes., Discussion: Careful tissue preservation and processing techniques minimize artifactual separation of the CV from the ILL. By optimizing the tissue architecture and antigenicity of the vitreoretinal complex, CV may be distinguished from the ILL immunohistochemically. The techniques described may be used to evaluate more effectively the utility of pharmacologic vitreolysis, using experimental animal models.

Purpose: To investigate the movement of intravitreally injected human serum albumin nanoparticles (HSA-NP) with respect to nanoparticle surface charge and retinal injury., Methods: HSA-NPs were developed by a desolvation technique. HSA-NPs were cationized by covalent coupling of hexamethylenediamine on the particle surface. Either anionic or cationic HSA-NPs were injected to determine the effect of surface charge on intravitreal nanoparticle movement. HSA-NPs were injected intravitreally into both normal and laser photocoagulated eyes to examine the effect of the integrity of retinal tissue on the retinal penetration. The retinal penetration of fluorescence labeled anionic HSA-NPs was investigated by confocal microscopy., Results: Anionic particles (-33.3+/-6.1 mV) more easily diffused through the 3-dimensional vitreal network of collagen fibrils than did their cationic counterparts (11.7+/-7.2 mV). In the laser photocoagulated retina, more HSA-NPs were detected in the choroidal space, compared to the normal retina. The immunohistochemical studies indicated that HSA-NPs were taken up into Müller cells., Conclusions: The movement of intravitreal nanoparticles depended on both nanoparticles surface charge and retinal injury. The Müller cells might play an important role in the retinal penetration of nanoparticles. The anionic HSA-NP is a promising drug or gene delivery carrier to the sub-retinal space and RPE.

The inner limiting membrane (ILM) and the vitreous body (VB) are two major extracellular matrix (ECM) structures that are essential for early eye development. The ILM is considered to be the basement membrane of the retinal neuroepithelium, yet in situ hybridization and chick/quail transplant experiments in organ-cultured eyes showed that all components critical for ILM assembly, such as laminin or collagen IV, are not synthesized by the retina. Rather, ILM proteins, with the exception of agrin, originate from the lens or (and) ciliary body and are shed into the vitreous. The VB serves as a reservoir providing high concentrations of ILM proteins for the instant assembly of new ILM during rapid embryonic eye growth. The function of the retina in ILM assembly is to provide the cellular receptor proteins for the binding of the ILM proteins from the vitreous. The VB is a gelatinous ECM structure that fills the vitreous cavity of the eye. Its major structural proteins, collagen II and fibrillin, originate primarily from the ciliary body. Reverse transcription-PCR and western blotting show that the rate of synthesis of structural, monomeric ILM and VB proteins, such as laminin, collagen IV and II is very high during embryogenesis and very low in the adult. The downregulation of ILM and VB protein synthesis occurs during early postnatal life, and both ILM and VB are from then on maintained throughout life with minimum turnover. Our data explain why ILM and VB do not regenerate after vitrectomy and ILM peeling.

Due to its function of light perception, the eye is exposed to high levels of radiation of the optical spectrum. Most of the ultraviolet and infrared radiation is absorbed in the cornea and lens, and mostly only radiation of the visible spectrum can reach the retina. Visible light can cause retinal damage by photomechanical, photothermal, and photochemical mechanisms. The most important mechanism of light damage to the retina under daily conditions or when using ophthalmologic light sources is the photochemical light toxicity caused by light-induced chemical reactions. The extent of damage depends on several factors, such as wavelength, exposure time, and irradiance. Particularly the shorter portion of the visible light spectrum (blue light) is responsible for photochemical damage to the retina.

Purpose: Light can cause phototoxic retinal damage. The aim of this study was to evaluate the risk of retinal hazard by endoilluminators during vitreoretinal surgery., Methods: The spectra, radiance, and irradiance of six light sources with different associated fibre optics (20 G, 23 G, standard collimated, wide-angle diffuse) were measured and compared with thresholds published by international standardisation committees., Results: The spectra of the endoilluminators differed significantly in the short wavelength band. The maximum radiance ranged from 15 mW to 190 mW and the calculated irradiance from 36 mW/cm2 to 1,130 mW/cm2 (distance 5 mm) and from 9 mW/cm2 to 376 mW/cm2 (distance 10 mm). Compared with published thresholds for surgery, time limits ranging from 0.7 min to 264 min (distance 5 mm) and 2.7 min to 1,052 min (distance 10 mm) seem to be safe., Conclusions: Light systems used for vitreoretinal surgery differ considerably in spectra, radiance, and irradiance; these differences have an impact on the maximum tolerable exposure times during surgery.

Purpose: To compare infusion and extrusion fluid volumes with three 25-gauge vitrectomy systems., Methods: The infusion and aspiration rates of 25-gauge systems from Alcon (Fort Worth, TX, USA), Bausch & Lomb (St Louis, MO, USA), and the Dutch Ophthalmic Research Centre (DORC, Zuidland, the Netherlands) were measured in vitro using balanced saline solution with different heights (40, 60, 80, 100, 120 cm) of infusion bottle, cutter velocities (800, 1100, 1500 cuts/ min) and aspiration powers (100, 200, 300, 400, 500 mmHg)., Results: The infusion flow velocities differed among the systems (p < 0.001 for all comparisons [p-values 0.0009-0.0001]). The aspiration rates of the Alcon and Bausch & Lomb systems were lower than that of the DORC system (p < 0.02 for all comparisons [p-values 0.018-0.002])., Conclusions: Infusion and extrusion fluid rates differ among 25-gauge vitrectomy systems. These results may help to optimize ideal aspiration and infusion parameters among 25-gauge vitrectomy systems used to treat vitreoretinal diseases.

Purpose: To evaluate the effect of intravitreal injections of triamcinolone acetonide (IVTA) combined with panretinal photocoagulation (PRP) on visual acuity (VA) and foveal thickness in patients with concomitant high-risk proliferative diabetic retinopathy (PDR) and clinically significant macular oedema (CSMO)., Methods: This retrospective interventional case series included seven eyes diagnosed with both high-risk PDR and CSMO that underwent PRP and a single injection of 4 mg of IVTA. The main outcome measures were VA and foveal thickness, measured by optical coherence tomography (OCT) before treatment and throughout the follow-up period., Results: Median follow-up was 301 days (range 180-715 days). Foveal thickness data were available for four of seven eyes. Before the combined treatment, median LogMAR (logarithm of the minimum angle of resolution) VA and median foveal thickness were 1 (Snellen 20/200, range 20/40-20/800) and 559 microm (range 333-689 microm), respectively. After treatment, median vision improved to LogMAR 0.544 (Snellen 20/70, range 20/40-20/1000) (P = 0.13). Vision improved or remained stable in six of seven eyes. Median foveal thickness at final follow-up was 436 microm (range 259-623 microm) (P = 0.15). Foveal thickness decreased or remained stable in all eyes., Conclusion: The addition of IVTA to PRP in the treatment of eyes with high-risk PDR and CSMO may prevent PRP-induced foveal thickening and loss of vision.

In this paper, we report a case of a post-traumatic Scedosporium endophthalmitis treated with a posterior vitrectomy, followed by intravitreal injections and systemic voriconazole. This is the second documented case of S. apiospermum endophthalmitis treated with voriconazole and the first case with intravitreal injections of voriconazole. A 29-year-old man developed endophthalmitis after being struck in the left eye by a chip from a swimming pool pump. Despite 3 weeks of prophylactic antibiotherapy, his visual acuity remained only for the perception of light and vitreous inflammation increased. A creamy-white fungal mass grew at the inferior peripheral retina and pars plana. The fungus was identified as S. apiospermum. Oral voriconazole, at 200 mg twice-daily, did not bring the infection under control, considering the low plasma and intravitreal concentrations. Before steady-state plasma voriconazole concentrations reached an efficacy level greater than minimum inhibitory concentration of Scedosporium, intravitreal injections of 64 ug/0.1 mL of voriconazole were initiated twice-weekly for 3 weeks. Administration of higher intravenous voriconazole doses (6 mg/kg b.i.d.) for 6 weeks was needed to achieve an antifungal effect without systemic dissemination.

A new self-illuminated and curved vitrectomy probe was designed for better accessibility of the peripheral retina, particularly in phakic patients. This probe has a 20-gauge pneumatic cutter. The curvature at the shaft has a 19.4-mm radius and is 25 mm long. A 2.5-cm piece of polyethylene terephthalate tubing (heat-shrink tubing) is threaded over both the probe and the 0.5-mm diameter fiberoptic light source to assemble the illuminated probe. Use of this instrument avoids inadvertent trauma to the clear lens in phakic eyes and allows the surgeon to illuminate the anterior vitreous with one hand while the other hand can be used to depress the sclera. This instrument complements wide-angle viewing for safe and quick surgical treatment of peripheral retinal pathology in phakic patients.

Objective: To evaluate the staining characteristics of bromphenol blue used during vitreoretinal surgery in humans., Patients and Methods: 13 patients with epiretinal membranes were included. Before and after surgery a complete clinical examination including best corrected visual acuity, funduscopy, fluorescein angiography, OCT (Stratus), Goldmann perimetry and multifocal ERG as well as photography of the macular area was performed. Bromphenol blue was used in concentrations of 0.2% in most patients. Removed epiretinal tissue was evaluated using electron microscopy., Results: Using dye concentrations of 0.2% a good demarcation of epiretinal membranes was seen in 11/13 patients. Staining of vitreous remnants at the vitreous base was seen in all patients. No dye-related adverse events were seen during follow-up in the functional tests (VA, ERG, perimetry) performed. Histological evaluation of epiretinal membranes showed unremarkable aspects of epiretinal cellular layers and unremarkable retinal surface of the internal limiting membrane (ILM)., Conclusion: Bromphenol blue appears to be a very helpful and safe tool in posterior segment surgery. The staining characteristics need to be further evaluated in prospective study settings and larger numbers of patients.

Purpose: To assess the histopathological findings of conjunctival specimens from patients submitted to vitreoretinal surgery with intraocular silicone oil injection., Methods: Prospective analyses of 30 eyes of 30 patients were evaluated. Before the patients underwent removal of the intraocular silicone oil, conjunctival excision was performed and submitted to histopathologic examination., Results: The presence of empty spaces corresponding to silicone oil location was positive in 10 (33%) specimens. The presence of inflammatory cells, vascular congestion, leukostasis, lymphocyte and monocyte infiltrates were positive in 27 (90%) specimens. The presence of silicone oil was positive in 10 (33%) specimens. Therefore, in those patients who undergo vitreoretinal surgery, silicone oil may be present in the conjunctiva or subconjunctival space, even if biomicroscopic examination seems to be normal. According to our knowledge, this is the first study with the purpose to assess the histopathological findings of conjunctival specimens from patients submitted to vitreoretinal surgery with intraocular silicone oil injection., Conclusion: Ophthalmologists should be aware of this possible complication after intraocular use of silicone oil after vitreoretinal surgery.

Background and Objective: Until now, UV lasers could not be applied to vitreoretinal surgery because of the absence of a practical beam guiding system. A flexible, freely mobile hollow core waveguide, capable of delivering UV laser light, was recently developed. We evaluated the feasibility of this UV laser guiding system for vitreoretinal surgery in enucleated porcine and rabbit eyes and in vivo on rabbit retina., Materials and Methods: 193-nm argon fluoride (ArF) excimer laser and a 5th harmonic Nd:YAG laser with the wavelength of 213 nm were used as a light source. A hollow core waveguide was connected to a handpiece with a 20-gauge endoprobe as an instrument for vitreoretinal surgery., Results: Cutting of the retina was possible only with contact technique. With a selected repetition rate of 20 Hz, sharp, full-depth dissection of porcine retinas was achieved only with 1.0 J/cm2. With the repetition rate of 50 Hz, even 0.05 J/cm2 could incise the total thickness of rabbit retina with no histological damage of the underlying retinal pigment epithelium. The ease in using the instrument for vitreoretinal surgery was confirmed by the in vivo experiment., Conclusion: This study revealed the potential use of the new type of the UV laser scalpel, connected to a hollow core waveguide, to perform precise, "cold," and tractionless cutting during vitreoretinal surgery., ((c) 2007 Wiley-Liss, Inc.)

Background: We explored the sympatholytic property of dexmedetomidine, especially its role in intraocular pressure (IOP) reduction, haemodynamic stability, and attenuation of extubation response., Method: In this double-blind, randomized, controlled trial approved by the Hospital Ethics Committee, 60 patients undergoing elective vitreoretinal surgery were allocated to two groups, receiving either placebo or dexmedetomidine. A loading dose of dexmedetomidine 2.5 microg kg(-1) h(-1) (or placebo in same volume) was infused for 10 min immediately before induction of anaesthesia with propofol, followed by a maintenance dexmedetomidine or placebo infusion at 0.4 microg kg(-1) h(-1) till 30 min before the end of the operation. Anaesthesia was maintained with isoflurane, oxygen, and air mixture. IOP was measured before the loading dose and 1 min after tracheal intubation. The mean arterial pressure (MAP) and heart rate (HR) during loading, induction, maintenance, extubation, and recovery period were measured. The degree of strain on extubation was graded from 0 to 5., Results: The use of vasopressor/labetalol/atropine and the reduction in IOP were comparable between the two groups. There was a significant variation in MAP and HR over time within group, but not between groups. The median degree of strain was significantly lower (P = 0.049), and the time to reach Aldrete score of 10 shorter (P = 0.031) in the dexmedetomidine group., Conclusion: Dexmedetomidine can be used without undue haemodynamic fluctuation and can decrease the excitatory response during extubation. The reduction in IOP with dexmedetomidine was comparable with placebo.

Objective: To evaluate peroperative pain management using a flexible spinal anesthesia catheter introduced into the retrobulbar space which allows injections of local anesthetics for vitreoretinal surgery., Methods: Twenty-five patients who underwent vitreoretinal surgery receiving retrobulbar anesthesia with 3.5 ml ropivacaine 0.75%. After injection, a catheter with spinal needle 22G x 1 1/2 (40 x 0.7 mm) was introduced to the retrobulbar muscle cone. The needle was withdrawn and the catheter was fixed. When the patient started to feel pain (grade 3 or higher), 2 ml ropivacaine 0.75% was administrated through the catheter during surgery or 2 ml ropivacaine 0.2% in the postoperative period. The catheter was removed 24- 48h later., Results: During surgery, 1 patient (4%) received a re-injection of 2 ml ropivacaine 0.75% because of pain. Three patients (12%) experienced pain of grade 3 or higher in the postoperative period and needed re-injection of 2 ml ropivacaine 0.2%. Re-injections were an effective method to achieve analgesia. Adverse effects were not noticed., Conclusions: The retrobulbar catheter technique is a procedure which allows multiple re-injections of local anesthetics; it provides adequate analgesia during surgery and rapid, effective and safe postoperative pain management.

A care system to maintain a comfortable prone position after vitreoretinal surgery was developed. Four positions and face-down gear including a TV-watching table were prepared in patients' rooms. Patients could take one position and then change to another position actively as desired. Thirty-nine patients used this system for 4 days after vitreoretinal surgery with intravitreal gas injection. Patients rated the system on a questionnaire. Patients who used the TV-watching table expressed more satisfaction than the patients who did not use it. Also, patients' active selection of various prone postures was important physically and mentally.