The role of funduscopy in severe thrombocytopenia: A prospective study

PurposePlatelet transfusions for patients suffering from severe thrombocytopenia are regulated by clinical bleedings and platelet counts. The aim of this study was to assess the prevalence of retinal hemorrhage in patients with hematologic and oncologic malignancies and severe thrombocytopenia, and to determine the benefit of systematic funduscopic examination in this setting.Materials and methodsHospitalized patients with hematologic and oncologic malignancies having a platelet count less than 25,000 per μL underwent indirect ophthalmoscopy. The prevalence of retinal hemorrhage and its correlation with different patients’ characteristics were determined. The decision to transfuse platelets or not following bedside indirect ophthalmoscopy was left at the discretion of the treating physician.ResultsA total of 34 severe thrombocytopenic patients were included in the study. The prevalence of retinal hemorrhage was detected in 10 patients (29.4%). No significant correlation was found between the occurrence of retinal hemorrhage and age, platelet count or thrombocytopenia etiology (P > 0.05). No significant difference was found concerning the rate of transfusion between those with and without retinal hemorrhage.ConclusionAccording to our statistical results, retinal hemorrhage is a frequent finding in severely thrombocytopenic patients. Early detection may lead to an increase in the platelet transfusion threshold from to 30,000 per μL offering additional protection against spontaneous bleedings. Funduscopy is a safe and easy exam to perform systematically in patients with severe thrombocytopenia.     

1.318 μm近红外激光视网膜损伤阈值研究

目的研究1·318μm激光对视网膜的损伤效应,确定其损伤阈值。方法用输出波长1·318μm的Nd∶YAG激光为照射光源,固定照射时间0·2s,以不同剂量的激光照射散瞳后的家兔(25只)和大鼠(28只)眼睛,照射光斑直径分别为5mm和2mm,于照后1h和24h观察视网膜损伤发生率,用加权概率单位法计算损伤发生率为50%时所对应的激光剂量,即损伤阈值ED50。并于照后24h对损伤视网膜做病理切片观察。结果1·318μm激光致家兔和大鼠视网膜损伤的阈值角膜剂量分别为13·7J/cm2和10·4J/cm2,阈值角膜能量分别为2·69J和0·33J。受损视网膜可见清晰的白色凝固斑,损伤重者累及视网膜全层。结论1·318μm激光可导致家兔和大鼠视网膜损伤,损伤阈值ED50分别为13·7J/cm2和10·4J/cm2。     

Light absorbing properties of indocyanine green (ICG) in solution and after adsorption to the retinal surface — an ex-vivo approach

BACKGROUND: To evaluate potential differences in light absorbing properties and stability of indocyanine green (ICG) adsorbed to the retinal surface and of ICG dissolved in water and balanced salt solution. METHODS: The retina of four human donor eyes was prepared by removing the vitreous from the retinal surface. The inner surface of the specimen was covered with two to three drops of a 0.05% or 0.15% ICG solution respectively. After 1 min, the dye was removed by careful irrigation using BSS plus. The retinal specimens were then investigated by diffuse reflection spectroscopy (UV/VIS/NIR Spectrometer Lambda 900/Perkin Elmer equipped with a PELA-1020 integrating sphere accessory) and their absorption evaluated by the Kubelka-Munk function. To control the sensitivity of the setting, diffuse reflectance spectra of ICG adsorbed to a cellulose membrane and Al(2)O(3) were measured. For comparison, absorption spectra of ICG dissolved in water and BSS plus solution were measured in relation to ICG concentration and time using an UV/VIS/NIR Spectrometer Lambda 900/Perkin Elmer. RESULTS: On the retinal surface, absorption spectra exhibited a steep increase of absorption beginning at 620 nm, with a maximum at 736 nm (0.05%) and a shoulder at 745 (0.15%) and a second maximum at approximately 800 nm for both concentrations. Repeated measurement of the retinal surface 13 days after the ICG exposure revealed no changes in the position of the maxima as compared to the initial measurements. Light absorbing properties of ICG on cellulose or Al(2)O(3) are similar to those seen on the retinal surface with respect to the pattern and location of absorption maxima. In contrast, ICG dissolved in water or BSS plus disclosed variations in absorption characteristics depending on dye concentration, solute and time of measurement. CONCLUSIONS: Absorption characteristics and stability of ICG bound to the retinal surface could be of relevance when investigating potential pathomechanisms of ICG related toxicity, which might be related not only to intraoperative but also to postoperative light exposure of patients after intravitreal use of ICG.     

Immunocytochemical staining of cholinergic amacrine cells in rabbit retina

Cholinergic neurons of rabbit retina were labelled with an antibody against choline acetyltransferase, the synthesizing enzyme for acetylcholine. Two populations of cells are immunoreactive. Type a cell bodies lie in the inner nuclear layer (INL), their dendrites branching narrowly in sublamina a of the inner plexiform layer (IPL), while type b cell bodies lie in the ganglion cell layer (GCL) with dendrites branching in sublamina b of the IPL. The irregular networks of clustered immunoreactive dendrites are similar, but not identical, in the two sublaminae. Type b cells are more numerous than type a cells in central retina. No axons were stained. It appears that the immunoreactive neurons are normally placed and displaced starburst/cholinergic amacrine cells.     

慢性高原病与视网膜改变

目的探讨慢性高原病(CMS)患者视网膜改变的特征,为高原眼病临床诊断提供参考依据。方法对移居海拔4300m、5100m、5380m10个月以上的407名男性青年采用CMS国际诊断标准[1]进行流行病学调查,将确诊为CMS的179人采用YZ-6B型强光源检眼镜分别进行视网膜检测,并行图表式记录。结果CMS患者眼底视网膜乳头充血、动脉痉挛、静脉怒张、视网膜渗出程度均为,发生率100%。结论CMS患者眼底呈暗红色,主要以动静脉比例增大为主,血管柱紫青或紫黑色,尤其是静脉增宽,似腊肠状,出现血管增多,并见乳头显著充血,网膜渗出。与急性缺氧期视网膜改变极其相似。     

维甲酸硅油的视网膜毒性实验研究

目的：了解维甲酸硅油对视网膜是否产生毒性。 方法：12只新西兰白兔的24只眼，随机分为3组，行气体压迫玻璃体手术3天后，分别向玻璃体腔内注入硅油(4只眼)、5μg/ml维甲酸硅油(10只眼)、10μg/ml维甲酸硅油(10只眼)各
0.5m1，用检眼镜、光漳和电镜检查来观察视网膜变化情况。 结果：注入硅油28天后，未发现各浓度的维甲酸硅油对视网膜产生毒性作用。结论：浓度为5、10μg/ml的维甲酸硅油注入玻璃体腔4周，对视网膜不产生毒性作用。 （中华眼底病杂志，1997，13：81-82）     

Reelin expression is upregulated following ocular tissue injury

Purpose Reelin is important in the guidance of neuronal stem cells in the central nervous system during normal development. We wished to determine whether reelin is expressed in the retina and cornea after injury. Methods Mice underwent laceration of their retina as well as corneal epithelial debridement. The mice were sacrificed at 3 days, and eyes were fixed and stained for reelin expression and reelin messenger ribonucleic acid (mRNA). Results In normal eyes, reelin was expressed only at very low levels in the ganglion cell layer of the retina and the endothelial cell layer of the cornea. In injured eyes, there was marked expression in reelin immunoreactivity in the retina and cornea. Reelin gene expression was seen in the retina and cornea. Conclusions Reelin is expressed during normal retinogenesis. This study shows that reelin is also upregulated following injury to the retina and cornea. The expression of reelin following injury suggests that reelin may play an important role in regulating stem cell trafficking in neuronal and nonneuronal tissues following injury similar to its role in normal organogenesis. For consideration of publication in Graefe’s Archive for Clinical and Experimental Ophthalmology.