大量玻璃体积血对兔视网膜电图检查的影响

目的研究大量玻璃体积血对兔眼视网膜电图检查的影响。方法(1)用物理学方法测量血液对白色闪光的透过率;(2)在经玻璃体气体压缩术形成的兔眼玻璃体腔中注入0.5ml自体血，利用强闪光视网膜电图(electrical resistance gauge,ERG)技术和光强度振幅曲线的计算分析ＥＲＧ的变化；测定玻璃体切除术消除积血前后ERG。结果随着浓度和厚度的增加，血液对光线的透过率呈指数下降趋势。玻璃体积血使常规ERG检查波形消失，用增强3.5log单位的强闪光刺激可以引出ERG波形。玻璃体切除术后ERGb波可逐渐恢复。结论血液对白色闪光有较强的吸收能力，光线被玻璃体内积血吸收可以导致常规ERG波形消失，此时应用强闪光ERG可以测得接近于正常的ERGb波最大反应，提示视网膜功能并未因玻璃体大量积血而发生不可逆病变。玻璃体切除术清除积血后，ERG波形缓慢恢复。(中华眼底病杂志,1998,14:104-107)     

Nonrecordable Electroretinogram in Vitreous Hemorrhage

A 32-year-old male sustained a dense vitreous hemorrhage following a scleral buckle procedure for a traumatic retinal detachment in his right eye. The bright-flash ERG was nonrecordable on two occasions. At pars plana vitrectomy, a dense vitreous hemorrhage was removed, and the retina was noted to be attached. The patient sub-sequently regained good vision with progressive recovery of the ERG over several months. Although a nonrecordable bright-flash electroretinogram is usually a reliable indication of a detached or severely impaired retina, recordings should be interpreted with caution in cases of dense vitreous hemorrhage, particularly if ocular penetration has occurred.     

Origin of simple glial epiretinal membranes in an animal model

Severe vitreous hemorrhage was simulated by the injection of 0.2 ml fresh uncoagulated autologous blood into the vitreous cavity of eight rabbits. Four weeks later, hemoglobin released from lysis of the original intravitreal clot had formed a thick layer on the retina. At this stage, many macrophages were conspicuous on the retinal surface and, in addition, in seven of the eight eyes, small cellular membranes were found by scanning electron microscopy. Light and transmission electron microscopy showed these membranes to be derived from accessory glial cells and their progeny. The membranes resembled the simple epiretinal membranes that occur in human eyes.     

A study of the ability of tissue plasminogen activator to diffuse into the subretinal space after intravitreal injection in rabbits

PURPOSE: Intravitreal injections of tissue plasminogen activator have been used to lyse fibrin from blood in the subretinal space, despite the lack of proof that tissue plasminogen activator can diffuse across the retina. We tested whether tissue plasminogen activator injected into the vitreous could penetrate the neural retina and enter the subretinal space. METHODS: We injected a mixture of 50 microg of tissue plasminogen activator (70 kD) labeled with fluorescein isothiocyanate and rhodamine B isothiocyanate-labeled dextran, which has a lower molecular weight (20 kD), into the midvitreous cavity of one eye in each of 18 rabbits. The eyes were enucleated after 3, 6, and 24 hours, and cryosections were examined with epifluorescent microscopy to determine the distribution of the labeled molecules. We also evaluated tissue plasminogen activator pharmacokinetics in one eye each of 18 rabbits in which a subretinal clot was induced by injecting autologous blood (50 microL) into the subretinal space through the sclera. Fluorescein isothiocyanate-labeled tissue plasminogen activator was injected into the vitreous 2 days after induction of the subretinal clot. RESULTS: Fluorescein isothiocyanate-labeled tissue plasminogen activator was present at the vitreal surface of the retina in a linear array in all 36 eyes studied, whereas the rhodamine B isothiocyanate-labeled dextran had diffused throughout the neural retina in the same sections. No fluorescein isothiocyanate signal was observed in the neural retina or in the subretinal clot. Vitreous hemorrhage caused by retinal perforation was observed in all eyes with intraretinal hemorrhage in which fluorescein isothiocyanate fluorescence was seen in the neural retina and inside the clot. CONCLUSION: Intravitreal tissue plasminogen activator did not diffuse through the intact neural retina to reach a subretinal clot. This study demonstrates no scientific rationale for the intravitreal tissue plasminogen activator treatment of submacular hemorrhage without vitreous hemorrhage presumably caused by an overlying retinal break.     

Intravitreal gas injection for the treatment of experimental vitreous hemorrhage in rabbits

PURPOSE: To determine the effectiveness of intravitreous gas injection in the management and clearing of experimental vitreous hemorrhage. METHODS: A total of ten New Zealand white rabbits received an injection of 0.4 ml of autologous blood into the vitreous of the right eye. After 24 hours of the vitreous hemorrhage simulation, six eyes were randomly assigned for treatment with na intravitreous injection of 0.2 ml of 100% perfluoropropane gas (C3F8) (group A), while four eyes received a control injection of an equivalent volume of balanced salt solution (group B). The persistence of vitreous opacification, which was graded at pre-established time points during 32 days of follow-up, was evaluated on the basis of visibility of retinal details in each of the four quadrants. RESULTS: In the gas-treated group (A), a partial view of the retina in the four quadrants was possible at 15 days, while at 32 days, the vitreous cavity was completely free of blood in all eyes, allowing unobstructed observation of the fundus. No retinal details could be observed in the control group after 32 days of follow-up. CONCLUSIONS: Gas injection proved effective in the treatment of experimental vitreous hemorrhage. It was significantly better than the injection of balanced salt solution, according to criteria of extension, intensity, and clearing time. Its technical facility, lack of complications, and low cost encourage additional research into gas injection to add knowledge to this initial study and to clarify its potential usefulness to treat persistent vitreous hemorrhage as well as to elucidate some unique pathophysiology features of blood catabolism in the vitreous.     

玻璃体积血对兔眼视网膜影响的研究

目的　观察兔眼玻璃体积血后不同时间视网膜电图（electroretinogram，ERG）及超微结构的变化，为玻璃体积血治疗及预后评估提供实验依据。方法　新西兰大白兔32只，右眼均为实验眼，自体全血0.2 mL玻璃体内注射构建玻璃体积血模型，左眼为空白对照眼。随机分为4组，分别于造模后3 d、7 d、14 d及30 d选取一组常规检查后记录ERG的变化，随后处死动物立即摘取眼球制备标本观察超微结构。结果　实验性玻璃体积血3 d后常规ERG波形消失，造模后7 d逐渐出现。强闪光源刺激下，造模后3 d实验眼ERG的b波振幅与a波振幅与对照眼相比均明显降低（均为P＜0.01）。a波振幅在造模后30 d明显恢复，与对照眼无明显差异（P＞0.05），较造模后14 d差异有统计学意义（P＜0.05）；b波振幅在造模后7 d时开始回升，与对照眼无明显差异（P＞0.05），较造模后3 d差异有统计学意义（P＜0.05），造模后14 d及30 d接近正常。扫描电镜显示实验眼造模后3 d无玻璃体后脱离（posterior vitreous detachment，PVD）发生，造模后7 d部分性PVD占1/8，完全性PVD占1/8，造模后14 d部分性PVD占2/8，完全性PVD占5/8，造模后30 d部分性PVD占1/8，完全性PVD占7/8；对照眼各阶段未见PVD发生。结论　玻璃体积血后约1周可轻度可逆地影响视网膜功能并加速导致PVD形成，为实验及临床判断玻璃体积血后视网膜功能变化和临床玻璃体手术治疗的时间窗的选择提供了参考。     

Rhegmatogenous retinal detachment and retinal tear with intravitreous hemorrhage

A retrospective study was conducted on a series of 28 eyes with primary retinal tears associated with vitreous hemorrhage. At initial presentation, the retina was detached in 17 eyes and attached in 11. In the series of eyes with an attached retina, the vitreous hemorrhage was massive in 5 eyes (45%), the average number of retinal tears was 1.36. All eyes showed a retinal tear located in the upper quadrants. Three patients (27%) experienced recurrent vitreous hemorrhage after sealing of the retinal tears. In the series of eyes with a detached retina, the vitreous hemorrhage was massive in 5 eyes (29%) and the average number of retinal tears was 1.9. The retinal detachment was located in the upper quadrants in 16 eyes (94%). Clinical evidence of proliferative vitreoretinopathy was noted, at initial presentation, in 6 eyes (35%). Permanent retinal reattachment was achieved in only 12 eyes (70%). All surgical failures were related to proliferative vitreoretinopathy. In the present series the prognosis of primary retinal tears with significant vitreous hemorrhage was guarded because of recurrent vitreous hemorrhages. The prognosis of primary rhegmatogenous retinal detachments with significant vitreous hemorrhage at initial presentation was guarded because of the high incidence of proliferative vitreoretinopathy.     

Terson's syndrome. Clinicopathologic correlations

In seven cases of Terson's syndrome, an elevated, dome-shaped, membrane was detected in the posterior pole by ophthalmoscopy, echography, or during pars plana vitrectomy. Light and electron microscopic examination of two additional eyes obtained postmortem from an acute case of Terson's syndrome revealed that the posterior vitreous face was elevated by blood and that the internal limiting membrane of the retina was intact and in its normal position. In two chronic cases, a dome-shaped epiretinal membrane was excised from the macula during vitrectomy. Light and ultrastructural studies demonstrated that the membranes consisted of glial cells and basement membrane material. The dome-shaped structure observed in eyes with Terson's syndrome is due to the formation of a subhyaloid hemorrhage. The partially detached posterior hyaloid face created by this hemorrhage provides a scaffold for cellular proliferation and the development of an elevated epiretinal membrane in long-standing cases. Echographically, this membrane resembles a retinal detachment in B-scans, but can be clearly distinguished from retina with standardized A-scan.     

Experimental studies of retinal glial cell proliferation on retinal surface

Our previous reports described the formation processes of epiretinal membranes composed of retinal glial cells in the experimental vitreous hemorrhage. This report presents the pathological changes of retinal glial cells, inner limiting membranes and vitreous body in the early stage of experimental vitreous hemorrhage. Using an operating microscope, 0.3 ml of autologous whole blood was injected through the pars plana into the vitreous cavity of albino rabbits. The eyes were enucleated at 3, 7, 10, 14 and 28 days after injection. Three days after injection, normal vitreous structure disappeared and vitreous fibers condensed. Seven days after injection, red blood cells were found on the retinal surface. The inner limiting membrane, composed of lamina rara and lamina densa, had a normal appearance. Where the red blood cell were present on the retinal surface, the lamina rara of the inner limiting membrane became thin. Fourteen days after injection, where glial cells showed upheaval, lamina rara disappeared and lamina densa became thin. Afterward, glial cells extruded their cytoplasmic processes onto the retinal surface. Twenty-eight days after injection, the inner limiting membranes were normal in appearance except for the area of glial cells penetrating the inner limiting membranes. The results suggested that, in vitreous hemorrhage, glial cell proliferation onto the retinal surface is an active reaction in order to engulf the debris of the red blood cells.     

眼外伤所致眼内病理膜的彩色多普勒超声诊断特点

目的探讨眼外伤所致眼内病理膜的彩色多普勒超声诊断特点。方法回顾性病例研究。选择2013年1-12月因眼外伤行眼部彩色多普勒超声检查的患者1 156例（1 162眼）,对其彩色多普勒超声诊断特点进行总结和分析,部分病例经手术确定诊断,判断彩色多普勒超声诊断的准确性。结果1 156例（1 162眼）的超声诊断包括玻璃体积血（1 071 眼）、眼内炎（78眼）、玻璃体后脱离（624眼）、视网膜脱离（521眼）、脉络膜脱离（221眼）、脉络膜上腔积血（117眼）等。眼外伤所致的玻璃体内膜状病变的彩色多普勒超声诊断特点为单一疾病表现典型,但多数患者存在2种或2种以上病变。应用彩色多普勒超声检查,在参考二维超声检查结果的同时,根据视网膜、脉络膜的血供特点,可以在错综复杂的眼内条带状回声中分辨出脱离的视网膜和脉络膜,为手术和治疗提供可靠的依据。本组部分病例经手术治疗。总体超声诊断与临床和手术诊断的符合率为99.1%。结论应用彩色多普勒超声检查眼外伤所致玻璃体内膜状病变是一种经济、简便、无创、可重复性好的诊断方法,根据视网膜和脉络膜的血流特征分析方法,可以提高超声诊断的准确性。     

Morphological study of epiretinal membrane following posterior penetrating injury in the monkey eye

Posterior vitreous detachment (PVD) and epiretinal membranes occur in a number of vitreoretinal diseases. We have developed an experimental model in which we can provide the morphologic correlation of these dynamic processes. The method provides the opportunity to study epiretinal membrane formation with the scanning electron microscope (SEM); with SEM, some epiretinal membranes that could not be readily detected either clinically or by routine light microscopy can now be identified and studied in detail. We performed an experimental posterior penetrating injury with injection of autologous whole blood or blood and lens material into the vitreous. Five eyes with posterior vitreous detachment but no retinal detachment were selected for SEM. A reduction in the cortical vitreous filaments and the presence of epiretinal membranes was apparent with SEM. In most areas the epiretinal membranes were separated from the internal limiting membrane by a narrow cleft; however, limited attachment sites between the epiretinal membranes and retina were observed in areas overlying retinal blood vessels. In two eyes we observed microscopic retinal folds beneath the membranes, demonstrating a possible morphologic correlation between epiretinal cellular contraction and traction on the retina.     

Echography of optic disc related pathology in diabetic retinopathy

Combined A- and B-scan examination of eyes with diabetic retinopathy and opaque media provides information about the presence and density of vitreous hemorrhages, can detect membranes inserting into the optic disc or the retina and differentiate them from retinal detachment. Absolute and relative indications for echographic examination are listed and some echograms concerning vitreous hemorrhage, proliferating membranes and traction retinal detachment are presented. The value of both A-scan standardized echography and contact B-scan technique for previtrectomy evaluation is stressed.     

Clinical and histological findings after intravitreal injection of bevacizumab (Avastin®) in a porcine model of choroidal neovascularization

Purpose: To examine the effect of intravitreally injected bevacizumab (Avastin^®) on the histological and angiographic morphology of choroidal neovascularization (CNV) in a masked and placebo‐controlled animal study. Methods: Choroidal neovascularization was induced surgically in 11 porcine eyes by perforating Bruch’s membrane with a retinal perforator. After closure of the ports used for the vitrectomy, which was performed to facilitate the Bruch’s membrane rupture, 0.05 ml of either bevacizumab or Ringer‐Lactat (placebo) was injected into the vitreous cavity. Eyes were enucleated after 14 days. Fundus photographs and fluorescein angiograms (FAs) were obtained immediately prior to enucleation. Sections of formalin‐ and paraffin‐embedded eyes were examined by light microscopy and by immunohistochemical staining. Results: Placebo‐injected eyes exhibited the highest propensity to leak, with five of six eyes leaking on FA, whereas only one of five bevacizumab‐injected eyes exhibited leakage. On histological examination, all 11 eyes contained CNV membranes of similar size, regardless of treatment. The number of vascular endothelial cells was significantly reduced (p = 0.03) in CNV membranes from eyes that had been injected with bevacizumab when compared with CNV membranes from placebo‐injected eyes. There was a trend towards more retinal pigment epithelium cells (p = 0.16) and fewer glial fibres (p = 0.08) in membranes from bevacizumab‐treated eyes compared with placebo‐treated eyes. Bevacizumab was identified immunohistochemically in the inner limiting membrane (ILM) and to a lesser degree in the remaining retina. Strong staining was also detected in both retinal blood vessels and entire CNV membranes with no cellular predisposition. Vascular endothelial growth factor expression was found in the CNV membranes, in the ILM, in the ganglion cell layer, in Müller cells throughout the neuroretina and in retinal blood vessels. Conclusions: Bevacizumab significantly reduced the proliferation of vascular endothelial cells in CNV membranes and showed a strong trend towards a reduction of leakage from these membranes. After a single injection, bevacizumab did not exhibit a size reducing effect on CNV, but it was still present in the membranes 14 days after intravitreal injection.     

玻璃体切除治疗复发性出血性玻璃体视网膜疾病

目的探讨玻璃体切除术对复发性出血性玻璃体视网膜疾病的临床效果。方法对43例(44眼)玻璃体积血施行三通道经睫状体平坦部玻璃体切除术,联合膜剥离,水下透热,眼内光凝(或经巩膜冷凝),并根据病情选用眼内长效填充材料。结果视网膜静脉阻塞18眼,外伤性玻璃体积血9眼,视网膜裂孔致玻璃体积血6眼,静脉周围炎5眼,增生性糖尿病视网膜病变3眼,蛛网膜下腔出血合并玻璃体积血(综合症)2眼,老年性黄斑变性1眼。术后随访2～24月,44眼视力均有不同程度的提高,随访视力较术前相比差异有统计学意义(P<0.05),视力0.05以上者36眼(81.82%),0.2～0.8者27眼(61.36%)。结论复发性出血性玻璃体视网膜疾病经药物治疗无效,B超显示出现玻璃体后脱离或B超显示伴有牵引性视网膜脱离者,玻璃体切除术是消除玻璃体积血并使视网膜复位的有效方法。     

Bright-flash electroretinography for the evaluation of eyes with opaque vitreous.

Standard retinal function tests are of limited value in assessing retinal function in eyes with opaque vitreous. We developed a method for obtaining an electroretinogram (ERG) from eyes with significant vitreous opacity by utilizing a much brighter than normal stimulating light. Of 115 eyes with vitreous opacities and good ERG responses to this bright-flash photostimulator, 47% would have been nonrecordable with a conventional ERG light source. Bright-flash ERG was often helpful in evaluating eyes with vitreous opacities for vitrectomy and was sometimes the only source of information regarding potential retinal function.     

Treatment of experimental vitreous hemorrhage with tissue plasminogen activator

Tissue plasminogen activator(tPA) is a fibrin-specific fibrinolytic agent that has recently been shown to be effective in accelerating the clearance of hyphema. Intravitreal injection of tPA can promote rapid lysis of experimental intravitreal fibrin clots. The purpose of this study was to investigate the efficacy of intravitreal tPA injection for the treatment of vitreous hemorrhage in normal phakic non-vitrectomized rabbit eyes. Vitreous hemorrhages were produced by intravitreal injections of 0.05 ml of autologous whole blood in 25 rabbit eyes with intact vitreous. The injection of 25 or 100 micrograms of tPA in 15 eyes resulted in the clearance of vitreous hemorrhage in 99 +/- 19 or 34 +/- 6.5 days, respectively. This was significantly faster than in the control eyes in which the clearance was not seen until 131 +/- 17 days later. No tractional retinal detachment was observed.     

Vitreous floaters

The vitreous changes in 148 eyes with sudden onset of floaters were evaluated biomicroscopically and documented photographically using an El Bayadi-Kajiura aspherical preset lens mounted on a photo slit lamp. Posterior vitreous detachment (PVD) was found in 83% of the eyes. In those eyes, the primary causes of floaters were prepapillary glial tissue on the posterior hyaloid membrane and minimal vitreous hemorrhage. In eyes with no PVD, intravitreous fiber-like opacities corresponding to the patient's symptoms were present in the posterior vitreous cavity near the retina. These opacities were found on the plicated membranes of Cloquet's canal, or were associated with liquefaction of the gel. The symptoms of patients 50 years of age or older were related to the acute onset of PVD in 95% of the cases. The complaint of multiple small floaters was frequently associated with vitreous hemorrhage and retinal breaks.     

玻璃体腔注C3F8治疗实验性兔玻璃体出血

目的 研究膨胀性气体Ｃ３Ｆ８对玻璃体出血机化有何影响。方法 新西兰大白兔８只,全麻下双眼抽取前房水０．１ｍｌ,平坦部注射自体抗凝血０．１ｍｌ。４８小时后,抽取眼前房水０．１ｍｌ,随机在各兔右眼或左眼注Ｃ３Ｆ８气体０．３ｍｌ于玻璃体腔内。另眼注０．１ｍｌ。４８小时后,抽双眼前房水０．１ｍｌ,随机在各兔右眼或左眼注Ｃ３Ｆ８气体０．３ｍｌ于玻璃体腔内。另眼注０．１ｍｌ的生理盐水作对照。术后散瞳查眼底及玻璃体。观察玻璃体出血和气体吸收情况。结果 注气眼与对照眼玻璃体出血的消退在时间上有显著性差异,Ｐ〈０．０５。对照眼最终有３只眼发生牵引性视网膜脱离。注气眼出血完全吸收后,均未发生视网膜脱离。未发生视网膜了眼,两组ＥＲＧ均正常,无明显差异。而有网脱的眼,ＥＲＧ明显下降。结论 Ｃ３Ｆ８气体在玻璃体手术和黄斑裂孔视网膜脱离的     

Avulsed retinal veins without retinal breaks

A localized segment of a retinal vein can be avulsed or torn from the retina by vitreous traction without a concurrent retinal break or tear. Eight eyes in eight patients (five women and three men, 20 to 69 years old) with avulsed retinal veins without retinal breaks showed a wide range of underlying retinal abnormalities, including background diabetic retinopathy, pars planitis, and involutional proliferative retinopathies. Such avulsed retinal veins often cause recurrent vitreous hemorrhage. Despite vitreous hemorrhages in six of the eight eyes, the visual prognoses were excellent in all eyes. An avulsed retinal vein must be considered in the differential diagnosis of those patients with proliferative retinopathies who have vitreous hemorrhage.     

外伤性视网膜脱离的玻璃体手术治疗

目的:评价外伤性视网膜脱离的玻璃体手术治疗方法及疗效。方法:对24例(24眼)外伤性视网膜脱离患者行常规经平坦部玻璃体切除、膜剥离、松解性视网膜切开、眼内激光、硅油或长效气体眼内填充等治疗,部分病例联合巩膜扣带术;随访3～24mo,观察疗效。结果:24眼术后视网膜均复位,视力均有不同程度的提高,随访期间,19例视网膜保持平复,5例复发视网膜脱离,其中3例经再手术视网膜复位,另2例因眼球萎缩未再手术。结论:外伤性视网膜脱离多伴有浓密的玻璃体积血、视网膜嵌塞及严重的增殖性玻璃体视网膜病变(prolifera-tivevitreoretinopathy,PVR),通过适时的玻璃体手术能获得比较满意的治疗效果。