Optical coherence tomography measurements of the fresh porcine eye and response of the outer coats of the eye to volume increase

Corneal and scleral thickness and anterior chamber dimensions are required for understanding developmental and pathological processes. Parameters of the eyeball are also required to calculate optical and material properties. As the eyeball resembles a pressure vessel, it has been suggested that elasticity of the cornea and sclera could be calculated from the measurements of thickness. Baseline corneal and scleral thicknesses and anterior chamber dimensions and how these change with incremental increases of intraocular fluid are measured in fresh porcine eyes using the Visante OCT (optical coherence tomography). At baseline, corneal thickness is almost constant. Anterior scleral thickness is variable, decreasing from 0.91+/-0.07 mm near the limbus to a minimum of 0.58+/-0.13. Posterior scleral thickness is more constant with an average of 0.78+/-0.09 mm. Near the optic nerve the thickness increases to 1.00+/-0.09 mm. Average baseline anterior chamber angle, diameter, and depth were found to be 33.15+/-4.91 deg, 13.60+/-0.38 mm, and 2.13+/-0.22 mm, respectively. After fluid injections, maximum changes in corneal and scleral thicknesses were 9 to 10 and 1 to 3%, respectively. Anterior chamber angle and depth decreased slightly but significantly. Changes in the eyeball coats with fluid injections, indicate that the pressure vessel model can be applied to the eye to calculate corneal and scleral elasticities.     

应用超声生物显微镜观察小梁切除术后的房角改变

目的 应用超声生物显微镜（UBM）观察原发性闭角型青光眼（PACG）小梁切除术后的房角改变。方法：PACG患者30人（30只眼），行巩膜板层下小梁切除术，分别于术前和术后使用UBM观察房角形态并测量。结果：术前2只眼存在睫状体脱离。ACD、AOD500,TIA、TCPD、ID1术前术后比较差异均无显著性（P〉0．05）。结论：UBM有利于发现青光眼手术前后的睫状体脱离。小梁切除术对PACG的房角结构无改善。     

激光周边虹膜切开术在急性闭角型青光眼的临床应用

目的观察激光周边虹膜切开术在治疗急性闭角型青光眼临床前期及间歇期的效果,探讨其作用机制。方法 49例78只眼闭角型青光眼行激光周边虹膜切开术,采用倍频532 nm激光烧灼、ND：YAG激光击穿周边虹膜,术后观察前房反应、眼压,随访3-12个月。结果所有眼术后均出现了虹膜炎性反应,1 d后消退;一过性眼压升高3眼（22-30 mmHg）,经处理后降至正常;前房出血2眼,1 d后吸收;角膜内皮损伤混浊2眼,3 d后消退。结论激光周边虹膜切开术并发症少,不影响降压效果,适合于急性闭角型青光眼临床前期及间歇期的治疗。     

Transversal phase resolved polarization sensitive optical coherence tomography

We present a novel optical coherence tomography (OCT) method to measure backscattered intensity and birefringence properties (retardation and fast axis orientation) and apply it to imaging of human ocular tissue. The method is based on a Mach Zehnder interferometer, on transversal scanning, and on a polarization sensitive two-channel detection. A highly stable carrier frequency is generated by acousto-optic modulators (AOMs). This allows a phase sensitive demodulation by the lock-in technique. Since the recording of individual interference fringes is avoided by this method the amount of data to be recorded and processed is considerably reduced. We demonstrate this method on human cornea and anterior chamber angle and present, to the best of our knowledge, the first OCT images of retardation and fast axis orientation of the anterior chamber angle region in vivo.     

白内障超声乳化摘除术联合房角粘连分离术治疗慢性闭角型青光眼的临床疗效观察

目的 观察白内障超声乳化摘除术联合人工晶体植入联合房角粘连分离术治疗慢性闭角型青光眼的临床疗效。方法 采取自身对照研究,对按照标准纳入我院的慢性闭角型青光眼患者30例（48眼）,行白内障超声乳化摘除术联合房角粘连分离术,术前及术后1 d、1周、1个月、3个月进行最佳矫正视力、眼压、前方深度、视野、房角开放程度、神经上皮层厚度等结局指标检测。结果 经治疗后,患者术前眼压（36.542±5.624）mmHg,术后3个月（13.958±1.821）mmHg,术后眼压均明显降低,达到正常范围（P＜0.001     

Spontaneous Anterior Lens Capsular Dehiscence Causing Lens Particle Glaucoma

To report acute onset lens particle glaucoma associated with a spontaneous anterior capsular dehiscence. A 66-year-old man presented with spontaneous anterior lens capsule dehiscence with an acute onset of right eye pain that was associated with white particles in the anterior chamber angle and intraocular pressure (IOP) of 55 mmHg. No trauma or other inflammatory antecedents were reported. A hypermature cataract was observed at slit lamp exam. After medical treatment without IOP control, we performed extracapsular cataract extraction and anterior vitrectomy. Anterior chamber aspirate confirmed the presence of macrophages. The postoperative IOP at one month was 16 mmHg OD without medication. Spontaneous dehiscence of the anterior lens capsule in a patient with a hypermature cataract may release lens cortical material, resulting in lens particle glaucoma. Prompt surgical removal of the lens material usually controls the high IOP, and the need for additional glaucoma surgery is not common.     

超声乳化联合房角分离术对青光眼合并白内障患者眼压、视力、中央前房深度改善的影响

目的:探讨超声乳化联合房角分离术对青光眼合并白内障患者眼压、视力、中央前房深度改善的影响.方法:选择2018年2月至2019年7月在我院接受治疗的青光眼合并白内障患者64例进行研究.采用随机数字表法将患者分为2组,每组各32例.对照组患者行超声乳化联合小梁切除术,观察组患者行超声乳化联合房角分离术.于术后1 M复查眼压...     

超声乳化白内障吸除术对老年闭角型青光眼患者血液流变学的影响

目的 探讨利用超声乳化白内障吸除术治疗老年闭角型青光眼患者前后血流动力学变化及治疗效果的影响。方法 86例老年闭角型青光眼患者,随机分为对照组(n=43)和干预组(n=43),并分别进行小梁切除、超声乳化白内障吸除手术治疗。观察分析两组患者的眼压、血液流变学指标,及其与视力、并发症发生率、前房深度、房角黏连闭合等治疗疗效相关性。结果 治疗前,两组患者的视力及眼压,血浆黏度、红细胞压积及血小板黏附率,前房深度及房角黏连闭合度,均没有显著性差异(P>0.05);治疗后,与对照组相比,干预组视力升高(P<0.05),且眼压降低(P<0.05),并发症发生率降低(P<0.05),血浆黏度、红细胞压积及血小板黏附率等指标均明显降低(P<0.05),前房深度及房角黏连闭合度改善程度均明显提高(P<0.05),治疗疗效明显提高(P<0.05)。结论 老年闭角型青光眼患者接受超声乳化白内障吸除术治疗可有效增强治疗疗效,使并发症发生率进一步降低,并促进患者眼压及视力改善,使患者前房深度及血流动力学稳定性显著提升,并能对房角黏连闭合进行有效控制,在老年青光眼治疗中...     

超声乳化联合房角分离手术治疗白内障合并青光眼的 临床价值及对房角宽度的影响

目的 探讨超声乳化联合房角分离手术治疗白内障合并青光眼的临床价值以及对房角宽度的影响。方法 选取我院眼科在2016年5月~2018年5月收治的120例白内障合并青光眼患者为研究对象,随机分为联合组和常规组,每组60例。常规组接受常规手术治疗,联合组在常规组的基础上应用超声乳化联合房角分离术,在术后对比两组患者的治疗效果、房角宽度以及并发症发生情况。结果 治疗后,两组患者的眼压水平相比较于治疗前均有所下降,且联合组优于常规组,差异具有统计学意义（P＜0.05）;两组患者的视力水平、房角宽度以及中央前房深度水平比治疗前都所有提升,且联合组优于常规组,差异具有统计学意义（P＜0.05）。联合组的并发症发生率低于常规组（11.67% vs 30.00%）,差异具有统计学意义（P＜0.05）。结论 在对白内障合并青光眼患者的手术治疗中,应用超声乳化联合房角分离术的治疗效果更优越,同时能提升房角宽度,降低并发症发生率。     

虹膜膨隆变形及房角开放度的实验研究

目的对原有实验系统进行改进,并对兔眼虹膜在不同前后房压强差产生的膨隆变形及房角开放度进行实验研究。方法在保持虹膜环状形态结构和组织活性特征的前提下,搭建模拟完全瞳孔阻滞和虹膜膨隆的实验平台,获得兔眼虹膜随前后房压强差变化时的膨隆变形二维图像;再利用立体视觉技术得到膨隆变形的三维信息,并计算出膨隆曲线上虹膜根部所在点的切线斜率和虹膜膨隆最高点的曲率半径,由此对房角开放度进行衡量。结果当前后房压强差在50～200Pa之间时,虹膜根部斜率在0.29～0.55范围内逐渐增大,曲率半径在16.13～6.67的范围内迅速减小,房角在30°～15°的范围内变化;而当前后房压强差增大到200～600Pa之间时,虹膜根部斜率在0.55～0.76的范围内逐渐增大,曲率半径在6.67～4.25的范围内逐渐减小,房角在15°～10°的范围内缓慢减小。结论本文提出了一种可行的定量研究虹膜膨隆变形及房角开放度的理论和实验方法,研究结果与临床观察及研究相一致。     

A boussinesq model of natural convection in the human eye and the formation of Krukenberg's spindle

The cornea of the human eye is cooled by the surrounding air and by evaporation of the tear film. The temperature difference between the cornea and the iris (at core body temperature) causes circulation of the aqueous humor in the anterior chamber of the eye. Others have suggested that the circulation pattern governs the shape of the Krukenberg spindle, a distinctive vertical band of pigment on the posterior cornea surface in some pathologies. We modeled aqueous humor flow the human eye, treating the humor as a Boussinesq fluid and setting the corneal temperature based on infrared surface temperature measurements. The model predicts convection currents in the anterior chamber with velocities comparable to those resulting from forced flow through the gap between the iris and lens. When paths of pigment particles are calculated based on the predicted flow field, the particles circulate throughout the anterior chamber but tend to be near the vertical centerline of the eye for a greatest period of time. Further, the particles are usually in close proximity to the cornea only when they are near the vertical centerline. We conclude that the convective flow pattern of aqueous humor is consistent with a vertical pigment spindle. © 2002 Biomedical Engineering Society. PAC2002: 4266Ew, 8710+e, 8719Pp     

Senile ocular amyloidosis in SAM and BALB/c strains of mice

We investigated whether amyloid deposition can affect retinal atrophy in old SAMR1, SAMP1 and BALB/c mice. Immunohistochemistry revealed that old SAMP1 mice showed the deposition of the murine senile amyloid protein fibril, AApoA-II in the subconjunctival tissue, the vessel walls near the chamber angle, and the sheaths of the external ocular muscles and the conjunctival glands, but was never observed in the retina or the choroid. Although the old SAMR1 mice also showed a remarkable loss of retinal photoreceptor and ganglion cells, they never showed any amyloid deposition. The BALB/c strain did not showed any amyloid deposition either. Our data suggest that atrophy of the retina is not related to senile systemic amyloidosis in mice.     

Detection of Occludable Angles with the Pentacam and the Anterior Segment Optical Coherence Tomography

Purpose

To assess efficacy of the Pentacam (PTC) and the anterior segment optical coherence tomography (AOCT) for detection of occludable angles.

Materials and Methods

Fourty-one eyes with gonioscopically diagnosed occludable angles and 32 normal open-angle eyes were included. Anterior chamber angle (ACA) and anterior chamber depth (ACD) were measured with PTC and AOCT. Receiver operating characteristic (ROC) curve was constructed for each parameter and the area under the ROC curve (AUC) was calculated.

Results

Values of ACA and ACD measured by PTC and AOCT were similar not only in normal open angle eyes but also in occludable angle eyes. For detection of occludable angle, the AUCs of PTC with ACA and ACD were 0.935 and 0.969, respectively. The AUCs of AOCT with ACA and ACD were 0.904 and 0.947, respectively.

Conclusion

Both PTC and AOCT allow accurate discrimination between open and occludable angle eyes, so that they may aid to screening the occludable angles.     

Anatomical study of the superior cerebral veins

The authors describe the number, courses, fixations and dispositions of the superior cerebral veins at the levels of the subdural space and of the superior sagittal sinus. It was observed that the superior cerebral veins have different courses to the superior sagittal sinus, and that these vascular walls are fixed to the intern face of the cranial dura-mater and to the lateral wall of the sinus. Frequently, the wall of the posterior vein adheres to the falx cerebri, presenting ascendant trajet to the inferior wall of the sinus. It was noted that the anterior veins open into the superolateral angle of the superior sagittal sinus, forming an acute forwards and right angle with it; the middle veins open near to the inferior angle of the sinus, with which they form an acute forwards or a right angle; the posterior veins enter the inferior angle of the sinus, forming an acute forwards angle with it. The authors confirm the superior cerebral veins draining into the superior sagittal sinus in sense favorable the current of the blood within it.     

Lesser anterior chamber dimensions in women may be a predisposing factor for malignant glaucoma

Malignant glaucoma is a potentially devastating complication of intraocular surgery that may also occur spontaneously. In this condition the aqueous is diverted into the vitreous, so the Iris lens diaphragm is moved forward. This causes shall owing of the anterior chamber and increasing of intraocular pressure. By reviewing 103 patients with malignant glaucoma, the disease was more prevalent in women that men (70% vs 30%). Anterior chamber dimensions in the women is 4% lesser than the men. Therefore, it is hypothesized that these may be due to more anterior position of the lens which not only causes lesser dimension of the anterior chamber but also more cilio-lenticular block and further aqueous diversion into the vitreous cavity, in the women.     

Immune privilege in the anterior chamber of the eye: alloantigens and tumour-specific antigens presented into the anterior chamber simultaneously induce suppression and activation of delayed hypersensitivity to the respective antigens.

Allografts placed into the anterior chamber of the eye enjoy prolonged and sometimes permanent survival while similar grafts are promptly rejected if transplanted to non-privileged sites. The immunological privilege of the anterior chamber is due, in large part, to the systemic suppression of delayed-type hypersensitivity (DTH) that is induced by anterior chamber presentation of alloantigens and is termed anterior chamber-associated immune deviation (ACAID). Although many categories of antigens elicit ACAID, strong tumour-specific transplantation antigens (TSTA) do not induce ACAID and instead, provoke potent DTH responses following anterior chamber presentation. The present study sought to determine if the anterior chamber were simultaneously confronted with these two categories of antigens, which systemic immune response would prevail: DTH or suppression of DTH? The results show that inoculation of minor histocompatibility alloantigens and TSTA into the anterior chamber induced both afferent and efferent suppression of specific anti-alloantigen DTH responses, yet simultaneously induced normal anti-TSTA DTH responses. Both responses (i.e. DTH and suppression) were transferable with lymphoid cells.     

Indoleamine 2,3-dioxygenase (IDO) is involved in promoting the development of anterior chamber-associated immune deviation

Indoleamine 2,3-dioxygenase (IDO), a rate-limiting enzyme in the tryptophan catabolism, has been shown to play an important role in various forms of immune tolerance. Since anterior chamber associated immune deviation (ACAID) is a systemic immune tolerance elicited by introducing exogenous antigens into the anterior chamber of the eye, we investigated the expression and function of IDO in the development of this ocular tolerance. ACAID was induced in BALB/c mice by an intracameral injection of 50mug ovalbumin (OVA). The IDO expression in the splenocytes during ACAID was determined by fluorescent quantitative real-time PCR, Western blot analysis and immunohistochemistry. The development of ACAID was evaluated by the delayed-type hypersensitivity (DTH) response after intraperitoneal injection of an IDO inhibitor 1-methyl-dl-tryptophan (1-MT). Secretion of IFN-gamma and IL-4 by splenocytes and lymph node cells from the mice treated with or without 1-MT were also evaluated using intracellular cytokine staining. Our results showed that the IDO expression was significantly increased at both mRNA and protein levels following OVA intracameral injection. Inhibition of IDO with 1-MT prevented the development of ACAID, which was indicated by the re-appearance of the OVA-specific DTH response. IL-4 was significantly reduced and IFN-gamma was partially recovered after the treatment of 1-MT. Our study reveal that IDO is up-regulated during ACAID and IDO inhibitor prevents ACAID generation, suggesting that IDO is involved in the development of this immune tolerance.     

Fluid flow in the anterior chamber of a human eye

A simple model is presented to analyse fluid flow in the anteriorchamber of a human eye. It is shown that under normal conditionssuch flow inevitably occurs. The flow, whose reduced Reynoldsnumber is small, is viscosity dominated and is driven by buoyancyeffects which are present because of the temperature differencebetween the front and back of the anterior chamber. In casesof severe eye trauma or as a result of certain diseases andmedical conditions, particulate matter may be introduced intothe anterior chamber. The motion and distribution of such particlesis analysed and it is shown that the model is capable of predictingwell-established and observed features that may be present ina traumatized eye such as hyphemas, keratic precipitates, hypopyonsand Krukenberg spindles.     

Chemotactic activity in aqueous humor from patients with anterior uveitis

Anterior uveitis, inflammation of the iris or ciliary body of the eye, may be associated with a variety of systemic diseases. Although a leukocytic infiltrate is characteristic of anterior uveitis, few studies have sought to detect factors in aqueous humor that could attract neutrophils or monocytes into the anterior chamber. Using modified Boyden chambers, we found that a 5% concentration of aqueous humor from patients with anterior uveal inflammation induced monocyte movement comparable to optimal or near-optimal concentrations of C (complement)5a or platelet-derived growth factor. Aqueous humor from patients with anterior uveitis induced significantly more monocyte migration than did aqueous humor from two sets of controls (either patients undergoing cataract extraction or patients with posterior uveitis). "Checkerboard" or gradient analysis indicated that a majority of inflammatory disease samples induced monocyte chemotaxis (directed migration) while the control aqueous humor consistently induced chemokinesis (stimulated random migration) (P less than 0.02). Despite their ability to induce monocyte migration, samples tended to induce minimal neutrophil migration with the exception of aqueous humor that was obtained from one patient with acute anterior disease. This sample induced marked chemokinesis. Identification of chemotactic activity may clarify the pathogenesis of uveitis and the characterization of leukocyte migration factors in aqueous humor may help define subsets of anterior uveal inflammation.     

小梁切除术后32例低眼压性浅前房临床分析

目的探讨青光眼小梁切除术后浅前房形成的原因。方法回顾调查2006年4月至2009年3月我院青光眼患者常规行小梁切除术的临床资料,对发生浅前房的原因及临床处理进行分析。结果 173眼临床资料中,术后发生低眼压性浅前房32眼,发生率18.5%,其中引流过畅24眼（75.0%）,结膜瓣渗漏6眼（18.7%）,睫状体脉络膜脱离2眼（6.3%）。经保守治疗后前房深度均恢复正常。结论低眼压性浅前房是青光眼小梁切除术后早期的主要并发症,引流过畅是最常见的原因。