Neovascularization of the iris: an experimental model in cats

Neovascularization of the iris was induced in cats by removing the vitreous and lens and creating a rhegmatogenous retinal detachment. The presence of new blood vessels on the anterior surface of the iris was verified from the second month onward by slit lamp examination, as well as by light microscopy six to twelve months after the operation. Control eyes undergoing vitrectomy and lensectomy, but without retinal detachment, did not develop rubeosis iridis. This model may allow investigation into causes and therapy of rubeosis iridis.     

Pathology of anterior chamber angle in diabetic neovascular glaucoma: extension of corneal endothelium onto iris surface

The purpose of this study is to elucidate the extension of the corneal endothelium onto the iris surface, a condition which has been found in the eyes with rubeosis iridis in various ocular disorders. Histopathology of the anterior chamber angle was studied by electron microscopy in 6 eyes with neovascular glaucoma occurring in the advanced stage of diabetic retinopathy. Histopathological findings embraced extensive peripheral anterior synechiae occluding the filtration angle and fibrovascular tissue on the anterior surface of the iris. In addition, formation of a continuous layer of endothelium was observable on the surface of the iris facing the anterior chamber in the 6 eyes. The newly formed endothelium was continuous with the corneal endothelium at the pseudo-angle formed by the attachment of peripheral anterior synechiae. Two types of corneal endothelial cells were found near the pseudoangle, one type with degenerative changes and the other apparently engaged in normal metabolic activity. It may be assumed from these findings that, while the corneal endothelium undergoes degeneration, new cells of unknown origin proliferate on the posterior corneal surface to replace the disrupted corneal endothelium and extend onto the iris surface.     

The association of rubeosis iridis with endothelialisation of the anterior chamber: report of a clinical case with histopathological review of 16 additional cases.

A patient is reported in whom the clinical observation of extension of the corneal endothelium and Descemet's membrane in association with rubeosis iridis was confirmed by histopathological examination. In a study of eyes which had been removed and demonstrated rubeosis iridis and secondary glaucoma in 16 additional eyes revealed extension of the corneal endothelium and Descemet's membrane on to the anterior iris surface. In all instances the transition occurred at the pseudoangle formed by the attachment of peripheral anterior synechiae. The suggestion is made that the fibrovascular membrane of rubeosis iridis is the stimulus which excites the extension of the endothelium on to the iris surface. The association between rubeosis iridis and extension of the corneal endothelium and Descemet's membrane on to the iris has not been previously appreciated.     

荧光素虹膜血管造影联合眼底血管造影在DR合并新生血管性青光眼中的应用

背景 新生血管性青光眼(NVG)是由视网膜缺血缺氧继发的眼病.荧光素虹膜血管造影(IFA)可早期诊断NVG,但其不能全面反映眼底血管情况.IFA联合荧光素眼底血管造影(FFA)可全面检测视网膜及虹膜新生血管情况,但目前国内关于糖尿病视网膜病变(DR)合并NVG患者中此方法的应用研究较少. 目的 探讨IFA联合FFA检查在增生性糖尿病视网膜病变(PDR)患者合并新生血管性青光眼的临床应用.方法 采用回顾性研究方法.纳入2013年2月至2016年1月在河南省立眼科医院接受IFA和FFA联合检查的PDR患者79例133眼,其中无虹膜病变100眼,I期青光眼红变期21眼,Ⅱ期开角型NVG 12眼.所有患眼均行视力、眼压、裂隙灯显微镜、IFA联合FFA检查.采用McNemar非参数检验法对比分析裂隙灯显微镜和IFA检查在I期青光眼红变期患眼检出率的差异. 结果 IFA检查显示100眼无虹膜病变患者无异常虹膜荧光素渗漏,FFA检查显示接受全视网膜激光光凝术(PRP)治疗的32眼未发现视网膜新生血管,68患眼存在视网膜新生血管;早期IFA检查显示,21眼I期青光眼红变期患者瞳孔缘或虹膜表面新生血管荧光素渗漏,FFA检查显示均存在视网膜新生血管;早期IFA检查显示12眼NVG患者虹膜表面新生血管荧光素渗漏,FFA检查显示均存在视网膜新生血管.I期青光眼红变期患眼中IFA检查的检出率为100％(21/21),明显高于裂隙灯显微镜检查的71.43％(15/21),2种检测方法检出率的比较差异有统计学意义(P=0.03). 结论 IFA联合FFA检查可以及早发现PDR合并青光眼红变期,有助于及时指导治疗.     

Iris melanocytoma mimicking the Cogan-Reese syndrome with monocular pigment dissemination

PURPOSE: To report a case of iris melanocytoma mimicking the Cogan-Reese syndrome. METHODS: A 37-year-old woman presented with pigmentary glaucoma in her left eye. There was diffuse pigmentary dispersion in the anterior segment, pedunculated pigmented nodules on the anterior iris surface, mild iris atrophy, and ectropion iridis. Neither intrinsic vasculature nor a sector cataract was found. The angle was open with marked trabecular pigmentation and no anterior synechiae. The intraocular pressure was 30 mmHg with maximum medical treatment and there was glaucomatous optic atrophy. The differential diagnosis included iris pigmented tumor and iridocorneal endothelial syndrome (Cogan-Reese syndrome). An iris biopsy was performed for diagnostic purposes. RESULTS: Histologic diagnosis after evaluation of the specimen was iris melanocytoma. CONCLUSIONS: This case presents signs considered quasi-pathognomonic of iridocorneal endothelial syndrome (Cogan-Reese syndrome): glaucoma, mild iris atrophy associated with pedunculated iris nodules, and ectropion iridis. Therefore, iris melanocytoma can present with features that mimic the Cogan-Reese syndrome.     

Glaucoma following retinal detachment operations

After retinal detachment operations 1–5% of the patients develop glaucoma. If this occurs directly after the operation it is the result of mechanical narrowing of the chamber angle.This can be the result of indentation due to an exoplant or encircling band causing forward displacement of the lens/iris diaphragm. Other causes are torsion of the ciliary body or a ciliary block due to serous detachment of the choroid caused by venous compression or diathermy.Ischaemia of the anterior segment sometimes leads to glaucoma in the long run; this is then the result of rubeosis iridis. Conducive factors are detachment of the recti muscles, arterial and venous compression by the exoplant or encircling band and the use of diathermy. When performing such operations it is advisable to take these risks into account and to keep a check on the intraocular pressure after the operation.A patient is described who, as the result of ischaemia, eventually developed ribeosis iridis with neovascular glaucoma, leading to loss of the eye.     

Nonteratoid medulloepithelioma of the ciliary body

A 34-month-old girl was treated for anterior uveitis, a superiorly subluxated cataract, rubeosis iridis and secondary glaucoma of the right eye of 3 months duration. She was diagnosed as having medulloepithelioma only after a mass was subsequently identified on the anterior surface of the iris. A low grade malignant nonteratoid medulloepithelioma was found to involve the ciliary surface throughout the circumference of the enucleated right globe. These tumors are generally associated with a good prognosis for survival, but are potentially lethal when they extend extrasclerally.     

Experimental immunogenic rubeosis iridis.

We have developed a primate model of rubeosis iridis in monkeys systemically sensitized to crystalline beef insulin. After intravitreal insulin injection, the dose-related immunogenic inflammation includes cells, flare, fibrin, and blood in the anterior chamber. With more severe inflammation, posterior synechiae, iris bombé, and cataracts occur. Of particular importance, new blood vessels develop within the stroma and on the anterior surface of the iris. Following injection of small amounts of insulin, the anterior surface vessels may regress over time, and the iris regains its normal appearance and coloration. However, the new stromal vessels persist and are cuffed by inflammatory cells including plasma cells. After injection of large amounts of insulin, more extensive structural alterations develop as noted above in conjunction with persistent iris anterior surface and stromal neovascularization. The relationship of rubeosis iridis to clinical inflammatory syndromes and to previous laboratory studies is discussed. Stromal neovascularization was a consistent finding in this experimental model even when anterior surface vessels regressed. On the basis of these experimental data and a review of publications describing human pathology, we believe that a broadening of the classic definition of rubeosis iridis is waranted to include a recognition of the stromal component of the clinical and pathologic findings.     

Latanoprost-induced iris darkening: a morphometric study of human peripheral iridectomies

PURPOSE: This microscopic study was undertaken to compare the melanocytes of peripheral iridectomy specimens from two eyes that had latanoprost-induced iris darkening (LIID) with iridectomies taken from the fellow untreated eyes. METHODS: The two patients in this study were the ones who underwent LIID in the latanoprost treated eye from a series of 17 patients requiring bilateral trabeculectomy. The first trabeculectomy procedure provided a control peripheral iridectomy for each patient, whereas the second eye was treated with once daily 50 microg ml(-1) latanoprost drops for 6 months. The four peripheral iridectomy specimens from the two LIID patients were subjected to quantitative morphometric analysis by light microscopy of iris cellularity, and electron microscopy of iris melanocyte immature melanosomes and mature melanin granules. RESULTS: There was no significant difference in stromal cellularity between the LIIDs and their respective controls nor were there significant differences in the numbers of immature melanosomes or melanin granules in the melanocytes. However, there was a significant increase in the diameter of melanin granules that was more pronounced in the anterior border layer than the deeper stroma. With the anterior border melanocytes, the increase in melanin granule size was associated with significant increases in granule area and the percentage of cell cytoplasm occupied by melanin (granularity). CONCLUSIONS: The only morphological change identified in two peripheral iridectomies that had LIID when compared to untreated fellow eye specimens was a modest increase in the size of stromal melanocyte melanin granules that was more pronounced in the cells of the anterior border region.     

A case of cholesterosis bulbi with secondary glaucoma treated by vitrectomy and intravitreal bevacizumab

We report on a case of cholesterosis bulbi concurrent with secondary glaucoma. A 36-year-old man, with a history of long-standing retinal detachment in his right eye after the irrigation and aspiration of a congenital cataract, presented with a clinical picture of elevated intraocular pressure and ocular pain. Upon slit-lamp examination, we found a ciliary injection and a pseudohypopyon of polychromatic crystals. Gonioscopic examination revealed a large amount of crystals deposited on the trabecular meshwork and mild rubeosis iridis, but the neovascularization of the angle could not be clearly confirmed due to the presence of so many crystals. Pars plana vitrectomy was performed to remove clusters of crystals and bevacizumab was injected intravitreally to treat iris neovascularization. Aqueous aspirate was examined by light microscopy and the typical highly refringent cholesterol crystals were identified. Intraocular pressure returned to a normal level after the bevacizumab injection, although severe cholesterosis was still evident in the anterior chamber. To our knowledge, this would be the first Korean case of cholesterosis bulbi combined with chronic retinal detachment and presumed neovascular glaucoma, which was treated by pars plana vitrectomy and intravitreal bevacizumab injection.     

Shock-wave effect on anterior segment structures following experimental neodymium:YAG laser iridectomy

The short-pulse laser may prove superior to the argon laser in producing noninvasive iridectomies. Little is known of the effects of the laser shock-wave on anterior segment structures adjacent to the iris. To investigate this question, iridectomies were produced in two owl monkeys using a neodymium (Nd):YAG laser and tissues were evaluated by light microscopy and scanning and transmission electron microscopy. For purposes of comparison, one eye received an iridectomy produced by an argon laser. Results indicate that while clean iris colobomas can be produced with a well-focused Nd:YAG laser, its shock-wave affects tissues in both the trabecular meshwork and corneal endothelium if the iridectomy is located within 0.8 mm of the limbus. No damage to the trabecular meshwork or corneal endothelium was evident after the argon laser iridectomy.     

Über die Feinstruktur der Pigmentflecken in der menschlichen Iris

Zusammenfassung Die Feinstruktur des Naevus iridis beim Menschen wurde mittels des Raster- und Transmissions-Elektronenmikroskops untersucht. Zur Vorderkammer hin finden sich in der Hauptsache abgerundete Zellen mit feinhöckeriger Oberfläche. Flache Deckzellen und spindelförmige Zelltypen sind selten. Das Cytoplasma der Naevuszellen findet sich dicht mit Pigmentgranula besetzt. Es weist außerdem einen ausgedehnten Golgi-Komplex mit Centrosomen, Mitochondrien, freie Ribosomen und Filamente auf. An der Zellmembran werden Pinocytosevesikel und charakteristische Membranspezialisierungen beobachtet. Die Bindegewebszellen im Naevusgewebe besitzen große Granula-Komplexe. Außerdem kommen normale Irismelanocyten vor. Die Naevuszelle ist ein hoch differenzierter Zelltyp, der strukturell dem Irismelanocyt nahesteht.

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The fine structure of pigment spots in the human irisA scanning and transmission electron microscopic study

Summary The fine structure of naevus iridis of the human iris was studied by scanning and transmission electron microscopy. Mainly rounded cells with a raspberrylike surface were found towards the anterior chamber. Flat covering cells and spindlelike cell types occur rarely. The cytoplasm of the naevus cells is densely filled with pigment granules. There is an extensive Golgi complex with centrosomes, mitochondria, free ribosomes and filaments. Pinocytotic vesicles and characteristic membrane specializations were observed at the cell membrane. The connective tissue cells of the naevus possess extensive accumulations of pigment granules. There are also melanocytes of normal appearance. The naevus cell is a further differentiated cell type which structurally resembles the iris melanocyte.

     

Open-angle Glaucoma Associated with Posterior Polymorphous Dystrophy: A Clinicopathologic Study

Clinical and histopathologic features of a 62-year-old black man with posterior polymorphous dystrophy and open-angle glaucoma requiring trabeculectomy are reported. The surgical procedure was modified to allow en bloc resection of the deep limbal tissue and peripheral iris. Light and electron microscopy of the specimen revealed a high insertion of the iris into the posterior portion of the trabecular meshwork with compression of the intertrabecular spaces. These findings are similar to changes that have been reported in primary congenital glaucoma and suggest a developmental anomaly of the anterior chamber angle in this form of glaucoma associated with posterior polymorphous dystrophy.     

Metastatic carcinoma of the iris.

Of three women and one man with metastatic carcinoma of the iris, the average age of the four was 50.2 years. Two of the tumors originated in the breast and two in the lungs. The average survival from time of diagnosis of the iris lesion was less than six months. Each patient presented with characteristic grayish-white translucent nodules on the iris or in the anterior chamber angle. The patients displayed other features of iris metastases such as secondary glaucoma, rubeosis iridis, iris atrophy, anterior uveitis, hypopyon, and hyphema. As an aid in the clinical evaluation, anterior segment fluorescein angiography was performed, revealing vascular details not seen clinically. Leakage of dye was a constant feature of the angiogram.     

Iris mammillations in ocular melanocytosis

Hyperpigmentation of the ocular tissues and of the skin around the eye is uncommon. In ocular melanosis, the episclera, uveal tract and the angle of the anterior chamber may be involved. Heterochromia iridis may be present, if the iris is affected. In oculodermal melanocytosis or the naevus of Ota, hyperpigmentation of the skin follows the distribution of the first and second divisions of the fifth cranial nerve. This report documents a patient with episcleral pigment, heterochromia iridis and numerous tiny pigmented nodules on the iris (mammillations). The possible significance of these findings is discussed.     

Etiology, pathogenesis, and diagnosis of neovascular glaucoma

Neovascular glaucoma is defined as iris and/or anterior chamber angle neovascularization associated with increased intraocular pressure. It is a secondary glaucoma that is most frequently caused by severe retinal ischemia. The most common diseases responsible for the development of neovascular glaucoma are diabetic retinopathy, ischemic central retinal vein occlusion, and ocular ischemic syndrome. Uncommon causes include ocular radiation, ocular tumors, uveitis and other miscellaneous conditions. Vascular endothelial growth factor is an important and likely predominant agent involved in the pathogenesis of intraocular neovascularization and neovascular glaucoma. The evolution of clinical and histopathological changes from predisposing conditions to the occurrence of rubeosis iridis and neovascular glaucoma is divided into four stages: prerubeosis, preglaucoma, open angle glaucoma, and angle-closure glaucoma.     

The arrangement of the connective tissue in the stroma iridis of man and monkey.

The arrangement of the connective-tissue fibres in the stroma of the iris of man and monkey (Macaca sp.) was studied with the scanning electron microscope. The stroma consists of a series of wide-meshed networks of collagenous connective-tissue bundles which run parallel to the surfaces of the iris. The rectangular areas isolated by the fibres of these networks are orientated in adjacent layers to form anterior-posterior canals. These canals communicate directly with the anterior chamber of the eye and extend to the muscles of the iris.The blood vessels of the iris are enveloped in sheaths of connective tissue. These sheaths consist of a number of layers of tightly woven networks of collagen fibres. Around the vascular tube the fibre bundles form more or less tight spirals and coil in alternate directions in conseeutive layers. The possible functional significance of this arrangement of the connective tissue in the stroma iridis is discussed.     

Preliminary report on effect of retinal panphotocoagulation on rubeosis iridis and neovascular glaucoma.

Eight eyes with central retinal vein occlusion one eye with old central retinal artery occlusion complicated by rubeosis iridis or increased intraocular pressure, or both; and one eye with diabetic retinopathy and rubeosis iridis were treated by retinal panphotocoagulation. Vision did not improve but intraocular pressure was lower and iris neovascularisation regressed in most cases, supporting the hypothesis that retinal hypoxia is a cause of iris neovascularisation and suggesting that retinal panphotocoagulation has a potential prophylactic and therapeutic role in rubeosis iridis and early neovascular glaucoma.     

Light and electron microscopy of the anterior iris surface in eyes with and without pseudo-exfoliation syndrome

Summary The anterior iris surface of 12 human eyes were studied by light and electron microscopy. Seven of these specimens were from eyes with capsular glaucoma, whereas the remaining 5 served as controls. In light microscopic sections large extracellular aggregates appeared within the anterior iris surface of the glaucomatous eyes, and in some cases such deposits formed a 25 broad zone along the anterior iris border. In the electron microscope these extracellular aggregates turned out to be pseudo-exfoliation material. It seems that the amounts of pseudo-exfoliation deposits within the anterior iris surface increase parallel with the progress of glaucoma.     

先天性青光眼虹膜血管的超微结构观察

对8例8只先天性青光眼虹膜手术切除标本进行了超微结构观察。结果显示:先天性青光眼的虹膜基质血管明显增多,管腔扩张。部分血管内皮细胞肿胀,基膜层次增多至2～4层。内皮细胞和其基膜分离形成间隙,间隙中可见块状纤维致密物沉积。对上述虹膜基质血管的病理改变及其临床意义进行了讨论。