硅油对角膜内皮的影响

目的：探讨硅油在不同情况下对角膜内皮的影响。方法;对１７０只眼行不同手术术前,术后２周,４周,８周及３个月时的角膜内皮细胞密度进行观察记录,同时对硅油人前房的２０只眼进行观察。结果;在眼压控制良好的情况下,有晶体眼行单纯玻璃体和切割术及玻璃体切割硅的填充术,无晶体眼行玻璃体切割硅油填充术。有晶体眼及无晶体眼行硅油取出术手术后各期内皮细胞密度与术前相比均无显著差异,有晶体眼行玻璃体切割晶体切割硅油填     

乳化硅油滴在活体角膜内皮的共焦显微镜表现

目的 采用角膜激光共焦显微镜观察乳化硅油滴在活体角膜内皮面的形态,比较并总结其特点.方法 应用自身对照研究.对近年来在深圳市眼科医院就诊的20例(20只眼)临床硅油乳化的患者采用激光角膜共焦显微镜检查其角膜,分析研究其图像特点,总结乳化硅油滴在活体角膜内皮的共焦显微镜表现.结果 乳化硅油滴在角膜内皮面有着不同的大小和排列方式,镶嵌于角膜内皮面,并伴有角膜内皮细胞的明显水肿增大,内皮细胞的结构不清,仅有模糊轮廓.结论 采用新型的激光角膜共焦显微镜可以观察到乳化硅油滴对角膜内皮细胞的直接损害.该检查是一种对人体无害、可以反复进行,并且连续观察角膜内皮变化的工具,对评估乳化硅油滴对角膜的损害具有重要作用.

Abstract：

Objective To study the emulsified silicone oil droplets in the corneal endothelium by in vivo laser confocal microscopy, compare and summarize its characteristics. Methods The corneas of 20 patients (20 eyes) with silicone oil emulsion were examined by in vivo laser confocal microscopy, analyzed the characteristics of the images, and summarized the performance of emulsified silicone oil droplets in corneal endothelium with confocal microscopy. Results Emulsified silicone oil droplets in the corneal endothelium had a different size and arrangement, embedded in the corneal endothelium and come al endothelial cells associated with increased edema; endothelial cell structure was unclear, with only vague outlines. Conlulusions New type of laser corneal confocal microscope can observe the corneal endothelium damage by emulsified silicone oil drops directly. The inspection is a harmless, can be repeated and continuous observation of corneal endothelial changes in the tools. The laser corneal confocal microscope plays an important role on the assessment of silicon emulsion oil droplets on the cornea in the damage.     

Pseudo-endothelial dystrophy associated with emulsified silicone oil.

PURPOSE: To describe endothelial changes associated with emulsified silicone oil. METHODS: Report of a case. RESULTS: A 77-year-old man had multiple and diffuse clear vesicles on the endothelium of his left eye (LE). The cornea was clear and thin. He had undergone pars plana vitrectomy and intraocular silicone oil injection 5 years before presentation. Specular microscopy revealed numerous small bubbles of emulsified silicone oil and a mild degree of endothelial damage. CONCLUSION: Emulsified silicone oil can adhere to the endothelium and induce an apparent droplet-like endotheliopathy.     

Specular and scanning electron microscopy in diffuse silicone keratopathy

In a 50-year-old man, penetrating keratoplasty was carried out to treat a diffuse silicone keratopathy that developed 2 years after a pars plana vitrectomy combined with an intravitreal silicone injection for a complicated retinal detachment in the only aphakic eye. At 2 weeks after the intravitreal silicone injection, specular microscopy revealed a mild pleomorphism in the corneal endothelium and an endothelial cell loss of 26%. After 5 months, a small silicone drop floated in the anterior chamber and the first signs of diffuse keratopathy were observed. At the same time, specular microscopy revealed severe damage to the endothelial cells and a cell loss of 69%. After the keratoplasty, scanning electron microscopy of the corneal button showed a filamentous structure of the posterior surface of the cornea, with fibroblast-like cells; the endothelial cells were absent.     

Silicone oil in the anterior chamber

A total of 42 cases (42 eyes) with silicone oil in the anterior chamber after pars plana vitrectomy (PPV) and after silicone oil injection into the vitreous cavity (SIV) were analyzed. The main complications caused by silicone oil were corneal endothelial cell damage and secondary glaucoma. Specular microscopy showed decreased cell density, apparent pleomorphism of endothelial cells, and increased corneal thickness. In some cases, edematous and necrotic endothelial cells were found. The characteristic optical artifacts resulting from silicone oil coming into contact with the endothelium, such as a bright reflex, reversed pattern of illumination, and interference fringes, were also observed. There was a definite correlation between elevated intraocular pressure (IOP) and the presence of silicone oil in the anterior chamber; the IOP dropped significantly on removal of the oil. The treatment and prevention of conditions involving silicone oil in the anterior chamber are briefly discussed.     

The etiology of transient endothelial changes in the human cornea

To investigate the etiology of contact lens-induced transient endothelial changes (blebs) in the human cornea, the effects of five different stimuli on corneal thickness and the appearance of the corneal endothelium were assessed. The stimuli included: (1) a silicone contact lens; (2) a silicone contact lens in combination with anoxia; (3) anoxia alone; (4) a thick hydroxyethyl methacrylate (HEMA) contact lens; and (5) a gas mixture of 9.8% carbon dioxide, 20.5% oxygen, and the balance nitrogen. The silicone lens alone produced no significant alteration in endothelial appearance and little change in corneal thickness. However, when nitrogen gas was passed in front of the lens, a typical bleb response was observed. This indicates that the physical presence of a contact lens is insufficient by itself to produce transient endothelial changes. Anoxia alone induced corneal swelling and endothelial bleb formation, indicating a metabolic component in the bleb response. The gas mixture containing 9.8% carbon dioxide also altered the endothelial appearance but had no significant effect on corneal thickness. The thick HEMA lens produced changes in both the appearance of the endothelium and corneal thickness. The only factor common to the stimuli which induced blebs would appear to be their ability to change the pH in or near the corneal endothelial layer.     

Endothelial involvement of injection of silicone into the vitreous body

Intraocular silicone oil tamponade is used as an adjunct to vitrectomy in the treatment of proliferative vitreoretinopathy. The authors analyzed the effect of silicone oil on the corneal endothelium in 28 patients (10 phakic and 18 aphakic). In the phakic group, the endothelial cellular loss is small, no significant. In the aphakic group, the endothelial cellular loss is 20%.     

Confocal microscopy of posterior polymorphous endothelial dystrophy

PURPOSE: To report the in vivo confocal microscopic findings of posterior polymorphous endothelial dystrophy (PPED). METHODS: Four patients with PPED from 2 unrelated families and 2 asymptomatic children of an index patient were included in this observational case series. The eyes of the 6 subjects were examined by confocal light microscopy. RESULTS: Confocal microscopy demonstrated craters, streaks, and cracks over the corneal endothelium surface. Pleomorphism and polymegathism were present in eyes with PPED. Guttae and clusters of abnormal endothelial cells were also identified in corneas of these PPED patients. These findings were absent in eyes without clinical manifestations of PPED. CONCLUSIONS: In vivo confocal microscopy is potentially useful for excluding suspected cases of subclinical PPED. Abnormalities in the Descemet membrane and endothelium were observed.     

玻璃体切割手术对角膜内皮细胞的影响

目的 观察玻璃体切割手术对角膜内皮细胞影响的相关因素。 方法 回顾分析21 3例玻璃体切割手术患者213只眼手术前及手术后1周、1、3个月时角膜内皮镜检查结果。其中单纯玻璃体切割手术78只眼，玻璃体切割手术联合白内障摘除手术135只眼；硅油填充34只眼，C³F⁸填充53只眼，无眼内填充物者126只眼。 结果 单纯玻璃体切割组、玻璃体切割联合白内障摘除后囊完整组手术前后不同时期角膜内皮细胞数差异无显著性的意义（P均>0.05）；无后囊且眼内填充C³F⁸或硅油组手术后较手术前角膜内皮细胞数明显减少，其差异有显著性的意义（P<0.05）。 结论 玻璃体切割联合白内障摘除且晶状体后囊不完整者，眼内填充C³F⁸或硅油对角膜内皮细胞有一定的损伤作用。（中华眼底病杂志，2004，20：101-103）     

硅油取出前后联合超声乳化白内障摘除术的临床分析

目的:对硅油填充眼硅油取出前后联合超声乳化白内障摘除手术的临床分析。 方法:玻璃体切割术后硅油填充眼并发白内障患者36例36眼,随机分为两组,一组硅油取出前行超声乳化白内障摘除术, 二组在硅油取出后联合超声乳化白内障摘除术。观察两组患者术中、术后并发症、术后前房反应、眼压、角膜内皮情况等。 结果:两组患者硅油均取出顺利,超声乳化白内障摘除植入人工晶状体,术中术后并发症对症处理。两种联合手术后角膜内皮细胞密度及六角形细胞比例下降,术后1wk六角形细胞比例、术后1mo细胞数量及形态均有显著差异（P<0.05）。 结论:硅油取出前联合超声乳化白内摘除术有相对轻的术后反应,术中并发症及更小的角膜内皮损伤。     

Evidence of silicone oil deposits via high resolution ultrasound

BACKGROUND: Using biomicroscopy the evidence of deposits of silicone oil in the anterior segment after vitrectomy is limited. We examined the anterior segment by high resolution ultrasound to verify the possibility to identify silicone oil. MATERIALS AND METHODS: Ten patients treated by vitrectomy with instillation of silicone oil were examined by high resolution ultrasound before and after the removal of silicone oil. The duration of silicone oil tamponade was at least 5 months. A 20-MHz-sectorscanner was used for examination. We compared the findings of ultrasound and biomicroscopy with groups of patients with or without pharmacological mydriasis, blue or brown colour of the iris. RESULTS: The patients treated by vitrectomy and instillation of silicone oil showed small high reflective structures at the endothelium, the anterior front of the iris and in the angle. These highly reflective structures were found more often before, less often after operative extraction of silicone oil and could not be shown in the control groups. Using biomicroscopy we could not see an equivalent to all of the highly reflective structures. CONCLUSIONS: The highly reflective structures we found by ultrasound are probably inclusions in endothelial cells, silicone oil-induced calcifications or free particles of silicone oil. High resolution ultrasound with a 20-MHz-sectorscanner can be used for identifying indication and localising of silicone oil in the anterior segment even if biomicroscopic signs are absent.     

Evaluation of corneal damage by combined phacoemulsification and passive efflux of silicone oil in vitrectomized eyes

PURPOSE: To evaluate the effect on the corneal endothelium of phacoemulsification combined with passive silicone oil removal and intraocular lens (IOL) implantation under topical anesthesia after pars plana vitrectomy. SETTING: Department of Ophthalmology and Otolaryngology, University of Bari, Bari, Italy. METHODS: This retrospective study evaluated the corneal endothelium in 17 consecutive patients (17 eyes) who had phacoemulsification with transpupillary passive silicone oil washout (1300 centistokes) through a posterior capsulorhexis and single clear corneal incision and foldable acrylic IOL implantation. The findings were compared with those in a control group of 17 patients (17 eyes) who had phacoemulsification with acrylic IOL implantation through a single clear corneal incision. All procedures were performed by the same surgeon using topical anesthesia. The preoperative and postoperative endothelial cell densities, coefficient of variation (CV), and percentage of hexagonal cells at the corneal center and peripheral temporal position, evaluated by noncontact specular microscopy, were compared between the 2 groups. The central corneal thickness and occurrence of keratopathy were also noted. RESULTS: The mean phacoemulsification and total ultrasound times did not differ significantly between the 2 groups. At 6 months, the mean endothelial cell loss was 284.50 cell/mm(2) +/- 462.3 (SD) (11.2%) in the study group and 200.15 +/- 117.9 cell/mm(2) (8.3%) in the control group (P=.87, unpaired t test). There were no significant between-group differences in the increase in the mean CV and the percentage of hexagonal cells. The mean pachymetry remained at preoperative values, with no difference between groups. Keratopathy was not observed in any patient. CONCLUSIONS: Passive silicone oil efflux caused significant endothelial cell loss and changes in endothelial morphology. Nevertheless, these modifications were well tolerated and minimally different from the results of trauma caused by standard phacoemulsification with posterior chamber IOL implantation.     

玻璃体切割术后早期角膜内皮细胞形态学改变

目的研究玻璃体切割术对晶体完整者角膜内皮细胞的早期影响。方法122例（131眼）行玻璃体切割术，其中无眼内充填46例（47眼），C3F8充填36例（38眼），硅油充填40例（46眼），分别在术前、术后1天、3天、5天和15天测量眼压、角膜内皮细胞密度、六角形细胞比例和变异系数。结果与术前相比，无眼内充填者眼压无明显改变，术后1天角膜六角形细胞百分数下降；C3F8充填术后1天眼压升高，角膜六角形细胞百分数术后1、3天下降；硅油充填术后1、3天眼压升高，角膜六角形细胞百分数术后1、3、5天下降；眼压升高与六角形细胞百分数下降显著相关。结论对于晶体完整者，玻璃体切割术后早期角膜内皮形态会受到一定的影响，可能主要由眼压及手术操作所致，在将眼压控制后，短期内即可恢复正常。     

Immunohistochemical localization of ATPase in human dysfunctional corneal endothelium

Previous light microscopic autoradiographic results from our laboratory have shown a quantitative decrease in ATPase pump site density in dysfunctional corneal endothelium. In order to develop antibody techniques to correlate these findings with electron microscopic localization of pump sites, three types of corneas with dysfunctional endothelium (Fuchs' endothelial dystrophy, aphakic and pseudophakic bullous keratopathy) and two types of corneas with functional endothelium (age matched eye bank and keratoconus) were obtained at the time of transplant surgery. Corneas were fixed, frozen and cryostat sections were incubated in a rabbit kidney ATPase primary antibody followed by incubation in an HRP-labeled secondary antibody. Functional endothelia showed dense antibody labeling along the lateral cell membranes and there was a substantial reduction in labeling along the lateral membranes of dysfunctional endothelia. Positive tissue controls of rabbit kidney showed HRP reaction product in the convoluted tubules. Control tissue, incubated in either non-immune serum or primary antibody preabsorbed with ATPase, confirmed the specificity by having diminished or no reaction product. These results provide immunohistochemical confirmation of our autoradiographic data showing a quantitative reduction in pump site density on dysfunctional corneal endothelium.     

Corneal endothelial permeability after anterior chamber silicone oil.

One of six silicone oils, differing in both viscosity and manufacture, was infused into the anterior chambers of rabbit eyes. Polydimethylsiloxane oil, 5000 cps, caused an increased corneal endothelial permeability to inulin and dextran at 24, 96, and 168 hours after placement into the eye. Intraocular pressures were slightly elevated in the experimental eyes, compared with contralateral controls, at 24 and 144 hours after infusion. The effects of five other oils on corneal endothelial permeability were examined 168 hours after infusion. All oils increased permeability and caused thinning of endothelial cells, together with the appearance of a retrocorneal membrane, except Dow Corning Medical Fluid 360. The results indicated that contact of most silicone oils with corneal endothelium rapidly induces physiologic and morphologic changes.     

Corneal endothelial evaluation after phacoemulsification and silicone oil removal via an anterior approach

PURPOSE: To determine the effect of simultaneous phacoemulsification and silicone oil removal via an anterior approach on the endothelial cell density (ECD). METHODS: In this prospective study, the authors measured the ECD before and 6 weeks after surgery using an automatic noncontact specular endothelial microscope. Nine patients underwent phacoemulsification and silicone oil removal via an anterior approach using a closed system and separation of irrigation/aspiration function. RESULTS: Of nine patients, four (five eyes) were diabetic and five (five eyes) were nondiabetic. The postoperative ECD of the entire population was statistically different (P<0.01) from baseline and the average endothelial cell loss was 6.7%. CONCLUSIONS: Combined phacoemulsification and silicone oil removal via an anterior approach using a close system and separation of irrigation/aspiration function is safe to the corneal endothelium.     

Non-invasive assessment of the donor corneal endothelium using ocular redox fluorometry.

AIMS: To investigate the usefulness of ocular redox fluorometry for evaluating donor corneal endothelial viability. METHODS: Corneas from 42 recipients of penetrating keratoplasty and four donor corneas were examined by ocular redox fluorometry. Autofluorescence from reduced pyridine nucleotides (PN) and oxidised flavoproteins (Fp) of the human corneal endothelium were measured non-invasively, and the PN/Fp ratio was used as a tissue metabolic indicator. Specular microscopy and electron microscopy were also performed. RESULTS: Both the quality of specular microscopic image and the PN/Fp ratio were significantly correlated with the degree of corneal endothelial damage determined by histological examination. Corneas with poor specular microscopic image showed significantly decreased PN/Fp ratio compared with corneas with good or fair specular images (p = 0.041 and 0.027, respectively). The PN/Fp ratio increased in corneas with mildly damaged endothelium but decreased in corneas with severely damaged endothelium determined by histological examination. Evaluation of corneal endothelium by combination of specular microscopy and ocular redox fluorometry showed excellent association with that of histopathological examination (p < 0.0001). CONCLUSION: Ocular redox fluorometry is useful for assessing donor corneal endothelial viability. Combination of ocular redox fluorometry and specular microscopy may increase the ability of donor cornea selection.     

Comparison of the effect of polymethylmethacrylate and silicone intraocular lenses on rabbit corneal endothelium in vitro

An in vitro comparison of corneal endothelial damage caused by polymethylmethacrylate and by silicone intraocular lenses was made. Endothelial damage was assessed by vital staining of corneal endothelium immediately following direct contact with an intraocular lens. Silicone lenses produced less damage than polymethylmethacrylate lenses. The difference could be attributed to a specific type of damage-membrane stripping-seen only after contact with polymethylmethacrylate lenses.     

Iridocorneal endothelial syndrome with contralateral guttate endothelial dystrophy. A light and electron microscopic study

Both eyes from a 75-year-old woman who had unilateral closed-angle glaucoma, characteristic endothelial specular microscopic findings, and slowly progressive tractional iris abnormalities consistent with essential iris atrophy were obtained postmortem and studied by light, scanning, and transmission electron microscopy. Clinically, the nonglaucomatous right eye had an open-angle, normal iris, and severe endothelial dystrophy with three-plus corneal guttae. In this eye, results of histopathologic examination disclosed marked endothelial degeneration and typical guttate excrescences on Descemet's membrane. In contrast, the endothelium in the fellow eye with the essential iris atrophy variant of the iridocorneal endothelial (ICE) syndrome was strikingly different. The endothelial cells were relatively well preserved and exhibited marked pleomorphism, anisocytosis, and flat, occasionally paired oval nuclei. Binucleate cells also were observed. The endothelial monolayer had secreted a new layer of fibrillar extracellular matrix material on the posterior surface of Descemet's membrane. Extracellular matrix material was found interposed between the iris and cornea in zones of synechial closure, and an endothelial membrane was present on the anterior surface of the iris. These observations support the hypothesis that the iris abnormalities in essential iris atrophy are secondary to endothelial proliferation. The endothelial cells displayed neither tonofilaments nor abundant apical microvilli. The latter observation suggests that increased numbers of endothelial microvilli are not responsible for the characteristic specular microscopic picture seen in the ICE syndrome.     

Acute corneal decompensation after silicone oil removal

Purpose: To assess acute corneal decompensation after silicone oil removal in some aphakic eyes with clear corneas whose anterior chambers were completely filled with silicone oil for a considerable period of time. Methods: Eight eyes of 8 patients who underwent vitrectomy and intraocular silicone oil injection were studied. All the eyes were aphakic and anterior chambers were completely filled with silicone oil. In all eyes, corneas were clear and no corneal finding indicating keratopathy was detected by slit-lamp microscopy before silicone oil removal. The mean silicone oil removal time was 4 months (range 2–7 months). A specular microscope was used for the evaluation of corneal endothelial changes and corneal pachometry was performed to observe corneal changes before and after the silicone oil removal in 5 eyes besides slit-lamp microscopy. The follow up period after silicone oil removal was 2–12 months (mean 6 months).Results: In all eyes severe corneal stromal edema and clouding was detected in the first day following silicone oil removal. Increased corneal thickness was seen in all eyes. Decreased (at or below critical levels) corneal cell density was detected by specular microscopy before and after silicone oil removal. No significant improvement was observed during the follow up period. Conclusion: Eyes whose anterior chambers completely filled with silicone oil could be evaluated as clear corneas by slit lamp microscopy despite severe endothelial damage. We recommend that eyes with silicone oil in the anterior chambers should be monitored by a combination of slit-lamp microscopic examination and specular microscopy to determine the relative corneal endothelial tolerance to the silicone oil and endothelial damage. Early removal of the silicone oil can be considered when the retinal adhesion allows.