Histopathology of neovascular tissue from eyes with proliferative diabetic retinopathy after intravitreal bevacizumab injection.

PURPOSE: To examine the histopathologic effect of a single intravitreal injection of bevacizumab on newly formed vessels in eyes with proliferative diabetic retinopathy (PDR). DESIGN: Interventional case series and laboratory investigation. METHODS: Two days after intravitreal injection of bevacizumab (1.25 mg/eye), pars plana vitrectomy or trabeculectomy was performed for the treatment of PDR or neovascular glaucoma (NVG) associated with PDR. Ten surgically removed preretinal proliferative tissues and 6 deep scleral flaps containing trabecular meshwork were fixed in 2% glutaraldehyde or 4% paraformaldehyde and were subjected to transmission electron microscopic analysis, immunohistochemical analysis, and terminal deoxyuridiine triphosphate (dUTP) nick-end labeling staining. Two surgically removed preretinal proliferative tissues and 2 deep scleral flaps from patients with PDR and NVG, but without preoperative intravitreal injection of bevacizumab (IVB), served as controls. RESULTS: In control tissues, vascular endothelial cells possessed many fenestrations and were accompanied by pericytes. Apoptotic vascular endothelial cells frequently were observed in tissue after intravitreal injection of bevacizumab, whereas they were not observed in control tissues. Additionally, no apparent fenestration was observed in newly formed vessels from either proliferative tissue or trabecular meshwork after intravitreal injection of bevacizumab. In both PDR and NVG tissues after intravitreal injection of bevacizumab, overexpression of smooth muscle actin was observed in newly formed vessels, suggesting that the treatment may have increased pericytes on the vasculature as compared with control tissue. CONCLUSIONS: Intravitreal injection of bevacizumab may induce changes in immature, newly formed vessels of PDR or NVG tissue, leading to endothelial apoptosis with vascular regression, while inducing normalization of premature vessels by increasing pericyte coverage and reducing vessel fenestration.

[Selective trabeculoplasty in combination with vasoactive agents in the complex treatment of primary open-angle glaucoma].

The purpose of the present study was to evaluate the efficiency of complex treatment that has pathogenetic effects on the developmental stages of primary open-angle glaucoma (POAG), by activating the trabecular network via selective laser trabeculoplasty (SLT) and by improving microcirculation with the vasodilator Cavinton Forte. Fifty-seven patients aged 48 to 70 years (72 eyes) who had a developed stage of POAG with uncompensated ophthalmotonus were followed up. Group 1 (a study group) comprised 35 patients (42 years) who received complex therapy (the vasodilator Cavinton Forte 10 mg thrice daily for 2 months along with beta-blockers and prostaglandins. Group 2 (a control group) consisted of 22 patients (30 years) who were first only antihypertensive therapy that did not differ from that taken in Group 1. The complex treatment in patients with the uncompensated developed stage of POAG made it possible to reduce opththalmotonus in 80.9% of the patients to 35% after single application of SLT, to lower intraocular pressure stably, to cause easy outflow of intraocular fluid 2 weeks after SLT, to have positive changes in the stereometric parameters in the optic disk and structural alterations in accordance with the GPS classification, and to discontinue topical antihypertensive agents in 14.3% of the patients.

Panretinal photocoagulation and photodynamic therapy for anterior segment neovascularization secondary to ischemic central retinal vein occlusion.

BACKGROUND AND OBJECTIVE: To compare the effects of panretinal photocoagulation (PRP) and photodynamic therapy (PDT) for anterior segment neovascularization secondary to ischemic central retinal vein occlusion (CRVO). PATIENTS AND METHODS: Fifty-seven eyes were randomized to receive standard PRP (19 eyes), selective PRP (20 eyes), or PDT (17 eyes). Selective PRP was performed only when iris neovascularization and/or angle neovascularization showed progression on weekly follow-up. Primary outcome measures were the extension of anterior segment neovascularization and the rate of neovascular glaucoma development. Secondary outcome measures included visual acuity results. RESULTS: After 12 months of follow-up, iris neovascularization extension was 0.52, 2.55, and 2.27 in the PRP, selective PRP, and PDT groups, respectively. Anterior segment neovascularization extension was 0.57, 1.50, and 1.27 in the PRP, selective PRP, and PDT groups, respectively. Both showed a statistically significant difference in the PRP group. The rate of neovascular glaucoma development was similar in the three groups. CONCLUSIONS: Although PRP was better at determining iris neovascularization and anterior segment neovascularization regression, the similar rate of neovascular glaucoma development found in the three groups indicates that anterior segment neovascularization secondary to ischemic CRVO can also be safely managed using selective PRP or PDT.

A case of Chandler's syndrome revealed by ultrastructural studies of the trabecular meshwork.

PURPOSE: To investigate ultrastructural changes in the aqueous outflow route and discuss the mechanisms associated with intraocular pressure (IOP) elevation in a patient with presumably early stage Chandler's syndrome. METHODS: A 47-year-old man underwent trabeculectomy because of elevated IOP. A specimen obtained during surgery was studied by transmission electron microscopy. RESULTS: Electron microscopy showed the presence of a monolayer composed of corneal endothelium-like cells and thick basement membrane-like material. Neovascularization was also observed in the corneoscleral trabeculum. CONCLUSIONS: Our results indicate that several mechanisms, including the formation of basement membrane-like tissue, infiltration of inflammatory cells and neovascularization, might contribute to the elevation of IOP in Chandler's syndrome. These may occur even when there is no history of conspicuous inflammatory reaction in the anterior ocular segments.

Review of the ischemia hypothesis for ocular hypertension other than congenital glaucoma and closed-angle glaucoma.

Experimentally induced ischemia of the endothelial cells surrounding the aqueous drainage sites led to a rise in intraocular pressure (IOP) in monkey and pigeon eyes. Clinical conditions associated with a rise in IOP in human eyes, e.g. peripheral retinal detachments, subluxated lenses, and occlusion of the internal carotid artery, can result in ischemia of the endothelial cells lining Schlemm's canal. These findings led to the hypothesis that ischemia of the endothelial cells of Schlemm's canal induces hypertension in human eyes. Thus, the ischemia hypothesis should be considered in discussions of the etiology of age-related open-angle glaucoma.

Expression of 5'-nucleotidase and alkaline phosphatase in human aqueous drainage channels.

PURPOSE: Lymphatic vessels and blood vessels can be distinguished histochemically by their expression of 5'-nucleotidase and alkaline phosphatase. The aim of this study was to compare the expression of these enzymes in human aqueous drainage channels with that seen in lymphatics and blood vessels. METHODS: Histological sections from the angular regions of human eyes were prepared both by enzyme histochemical and immunohistochemical methods to analyse 5'-nucleotidase and alkaline phosphatase expression. In some of these eyes, Indian ink-stained gelatin was injected into Schlemm's canal and the suprachoroidal space to facilitate the identification of aqueous drainage routes. RESULTS: There was no expression of 5'-nucleotidase in the endothelium of aqueous drainage channels. Ocular blood vessels were characterized by strong expression of alkaline phosphatase, whereas the cellular lining of Schlemm's canal, the collector channels, the aqueous veins and a scleral channel from the suprachoroidal space showed significantly weaker expression or no expression at all. CONCLUSION: The study failed to show a histochemical similarity between lymphatics and human aqueous drainage channels, as no expression of 5'-nucleotidase could be found in any part of the aqueous outflow pathway. The endothelium of aqueous drainage channels also differed from normal blood vessels by a much weaker expression of alkaline phosphatase. This makes a histochemical distinction between aqueous veins and scleral veins possible.

Pathological study of cases with secondary open-angle glaucoma due to sarcoidosis.

PURPOSE: To investigate the cause of secondary open-angle glaucoma due to sarcoidosis. DESIGN: Observational case series studied by histological methods. METHODS: Seven trabeculectomy specimens from six patients with secondary open-angle glaucoma due to ocular sarcoidosis (trabeculectomy group) and anterior parts of seven autopsy eyes from four patients (autopsy eye group) diagnosed as confirmed sarcoidosis were processed for light and transmission electron microscopy. Pathological changes of outflow routes were investigated. RESULTS: Granulomata were found in three eyes of the trabeculectomy group and in three eyes of the autopsy eye group. Part of the Schlemm canal was occluded and replaced by fibrotic tissue and it became narrow in four eyes of the trabeculectomy group and three eyes of the autopsy eye group. The spaces of the trabecular meshwork appeared wide, even in the area close to granulomata and peripheral anterior synechia of the iris. Infiltration of lymphocytes, monocytes, and macrophages around the Schlemm canal was found in all eyes of the trabeculectomy group and in four eyes of the autopsy eye group. The infiltration of these cells was observed not only in the inner wall, but also in the posterior outer wall of the Schlemm canal and the collector channels. CONCLUSION: "Schlemm canalitis" is proposed from the results of inflammatory cell infiltration around the wall of the canal. The occlusion of the Schlemm canal by granulomata or fibrotic tissue replacement of the canal may play an important role in secondary open-angle glaucoma due to sarcoidosis.

Neovascularization in the anterior segment of the rabbit eye by experimental anterior ischemia.

PURPOSE: To investigate the effects of anterior ischemia accompanied by neither retinal nor choroidal ischemia on the anterior segment of the eye. METHODS: Both long posterior ciliary arteries in the right eye of 14 rabbits were directly cauterized with an electric coagulator. The eyes were enucleated 1, 2, 4, 7, 9 or 14 days after cauterization, then fixed with 4% paraformaldehyde. Semi-thin sections were studied by light microscopy. Several sections were stained with Griffonia simplicifolia lectin, which bound specifically to mammalian vascular endothelium. Other specimens were examined immunohistochemically for vascular endothelial growth factor (VEGF) protein. The tissue specimens of the first postoperative day were studied for expression of VEGF mRNA by in situ hybridization. RESULTS: Atrophy of the iris and ciliary body was seen after the second postoperative day. Corneal neovascularization appeared after 7 days. Neovascularization on the anterior surface of the iris and in the trabecular meshwork was detected after the ninth postoperative day. The proliferative tissues with newly formed vessels obstructed the iridocorneal angle 14 days after the treatment. There was no histological change in either the retina or choroid. Immunohistochemically, VEGF protein was detected in the epithelial and vascular cells of the iris on the first and fourth postoperative day. Expression of VEGF mRNA was detected in the epithelial cells of the ciliary body on the day following the treatment. CONCLUSIONS: Anterior segment ischemia, when unaccompanied by retinal ischemia, causes neovascularization in the cornea, iris and trabecular tissue.

Retinal ischemia and angle neovascularization in proliferative diabetic retinopathy.

PURPOSE: To analyze the relationship between the extent of retinal ischemia in proliferative diabetic retinopathy and angle neovascularization. METHODS: Panoramic fundus fluorescein angiography and 360-degree fluorescein gonioangiography to detect the angle neovascularization were performed on 70 eyes of 46 patients with proliferative diabetic retinopathy. Statistical significance was evaluated by chi-squared test. Statistical significance was evaluated if the value (T) was greater than the level of significance, chi(0.05)(2)(2) = 5.99. RESULTS: Retinal ischemia in fluorescein angiography was evaluated in four areas: capillary occlusion in (1) temporal raphe; (2) radial peripapillary capillaries; (3) the midperiphery (grade I, less than 25% of the area; grade II, 25% to 50%; grade III, 50% to 75%; grade IV, more than 75%); and (4) optic disk with neovascularization. The angle neovascularization was divided into two types: type I (14 eyes) and type II (12 eyes). Capillary occlusion in the temporal raphe and radial peripapillary capillaries, and papillary leakage significantly increased the risk of angle neovascularization (T = 8.28, 10.04, 6.44 respectively). Grade III and IV capillary occlusion in the midperiphery had a significant risk of angle neovascularization when compared with grade I (between grade III: T = 9.03, grade IV: T = 19.36) and II (between grade III: T = 6.31, grade IV: T = 16.09). CONCLUSION: Risk factors for angle neovascularization were retinal nonperfusion in the midperiphery wider than grade III, capillary occlusion in the radial peripapillary capillaries and temporal raphe, and optic disk. Fluorescein gonio angiography was found to be a powerful tool for the early detection of angle neovascularization, especially in dark irides.

Effects of aging on fluorescein leakage in the iris and angle in normal subjects.

PURPOSE: To determine the presence of fluorescein leakage from the iris and angle in normal subjects, and how it is affected by aging. METHODS: The subjects were 92 normal volunteers and patients with senile cataract who ranged in age from 20 to 93 years and were free from any systemic or ocular diseases. Fluorescein iris and angle photography and color iris and angle photography were performed using a goniolens and a photo slit lamp. RESULTS: Radial ciliary body vessels were found in 22 eyes (24%), radial iris vessels or trabecular vessels in 7 eyes (8%), and circular ciliary band vessels were seen in 4 eyes (4%). Goniovessels were found in 8 of 30 eyes (27%) of those under 50 years of age. No significant difference in the incidence of goniovessels was found between those over and under age 50 (P < .01). In the pupillary margin, fluorescein leakage was seen in 1 of 30 eyes (3%) in the age group under 50 years, whereas leakage was found in 30 of 62 eyes (48%) in the age group over 50 years. In the anterior chamber angle, leakage was seen in 4 of 30 eyes (13%) under age 50 years, and in 38 of 62 eyes (61%) over age 50 years (P < .05). CONCLUSIONS: These findings suggested that the incidence of leakage of fluorescein from the pupillary margin and anterior chamber angle tends to increase with age. Thus, when leakage of fluorescein in angle and iris is observed, it is important to consider the physiological changes resulting from aging.

Expression of factor VIII-related antigen in human aqueous drainage channels.

PURPOSE: Previous studies have indicated that there are preformed channels at the inner aspect of the anterior sclera, capable of draining fluid from the suprachoroidal space into scleral veins. The aim of this study was to characterize the cellular lining of these channels, and to compare it with the endothelium of Schlemm's canal, the collector channels and the scleral blood vessels. METHODS: Histological sections from the angular region of human eyes were prepared by an immunoperoxidase method to evaluate the expression of factor VIII-related antigen in different aqueous drainage channels. RESULTS: The cellular lining of the scleral channels showed a weak immunostaining to factor VIII-related antigen. Factor VIII-related antigen was also detected in the endothelium of the collector channels and Schlemm's canal. CONCLUSION: The positive immunoreaction to factor VIII-related antigen indicates that the previously described scleral channels, the collector channels and Schlemm's canal are all lined by an endothelium derived from a vascular origin.

Blood-aqueous barrier in pseudoexfoliation syndrome: evaluation by immunohistochemical staining of endogenous albumin.

BACKGROUND: Alterations of the integrity of the blood-aqueous barrier (BAB) are frequent findings in eyes with pseudoexfoliation syndrome (PSX). METHODS: Immunohistochemical staining for the demonstration of albumin was used to analyze the BAB in 10 eyes with PSX without previous intraocular surgery and in 10 age-matched normal control eyes. RESULTS: In eyes with PSX, small amounts of albumin were detected along the anterior surface of the iris in 7, in the anterior chamber in 1, along the ciliary epithelium in 4, and in the trabecular meshwork in 9 of 10 eyes. PSX material was also immunoreactive. In the 10 normal control eyes, albumin was detected anterior to the iris stroma in 1 eye, in the anterior chamber in 2 eyes, in the trabecular meshwork in 1 eye, but not internal to the ciliary epithelium. CONCLUSIONS: Our findings indicate that impairment of the BAB in PSX can be localized at the level of the iris and, less frequently or to a lesser extent, at the level of the ciliary body.

Anterior chamber angle vascularization in Sturge-Weber syndrome. Report of a case.

The case of a 20-year-old woman with a left-sided facial hemangioma and a homolateral glaucoma is reported, complete with the histology of a trabeculectomy specimen. Her left eye had an episcleral hemangioma and goniodysgenetic features in the anterior chamber angle, while the intraocular pressure was measured to be 45 mmHg. The left optic disc showed a large cupping and the left visual field was constricted. The right eye had no glaucomatous changes. Histological examination of the trabeculectomy specimen by both light and electron microscopy showed multiple congenital anomalies. There was a cluster of blood vessels in the trabecular meshwork. Abnormal accumulations of fine granular extracellular matrixes were observed in both the juxtacanalicular connective tissue and around the vascular structures. The lumen of Schlemm's canal was subdivided into three or four parts with few giant vacuole structures. The endothelial cells lining the inner wall of Schlemm's canal contained a well-formed basal lamina with many villi projecting into the lumen. These findings suggest that the multiple anomalies observed in the trabecular tissue may contribute to the manifestation of glaucoma in Sturge-Weber syndrome.

[Clinico-morphologic research on the initial stage of open-angle glaucoma in patients of various ages]. / Kliniko-morfologicheskie issledovaniia nachal'noi stadii otkrytougol'noi glaukomy u bol'nykh razlichnogo vozrasta.

The paper analyses results of clinical examination of patients with initial open-angle glaucoma--44 eyes of patients under 44 years of age and 96 eyes of patients above 50--and those of morphologic studies of 16 biopsies of the drainage zone of the eyes obtained at sinusotrabeculectomy in young and elderly patients. A complex investigation of the initial stage of open-angle glaucoma has shown identical clinico-morphologic changes responsible for this form of the disease in patients at any age. This identity is manifested itself by similar hydro- and blood microcirculatory disturbances, changes in the anterior chamber angle structures differing only quantitatively in patients of various age. Some distinctive peculiarities in the course of open-angle glaucoma are also noted in persons of young age. Morphologic studies have revealed qualitative differences in glaucomatous patients of young age, such as specific structures of collagenous fibers peculiar to embryonic period.

Carbon dioxide laser trabeculostomy for the treatment of neovascular glaucoma.

During the past 18 months, 23 cases of advanced neovascular glaucoma, unresponsive to medical therapy, have been treated by a trabeculostomy procedure using a carbon dioxide laser. This procedure entails surgical entry into the anterior chamber from beneath either a conjunctival or a scleral flap in such a way as to completely cauterize any neovascular tissue in the iridocorneal angle and to permit adequate drainage of the aqueous fluid from the anterior chamber to the periocular space. The average intraocular pressure, prior to carbon dioxide laser trabeculostomy was 54 mm Hg and these pressures were lowered below 18 mm Hg in over 57% of the cases followed for longer than six months post-laser therapy. Treatment was considered a failure in 26% of the cases where the intraocular pressure was not lowered substantially, and 17% of the treated eyes sustained a pressure decrease to within the 25 to 35 mm Hg range. Carbon dioxide laser trabeculostomy or trabeculo-sclerostomy provides a new method of lowering the intraocular pressure in severe cases of neovascular glaucoma without the hazard of intraocular hemorrhage, common with other filtration procedures. These procedures have proved satisfactory in alleviating the high pressures of neovascular glaucoma in a relatively large proportion of the patients treated. If the eye is grossly hyperemic and irritated because of the high intraocular pressure and the deteriorated condition of the eye, it is suggested that the carbon dioxide laser trabeculostomy procedure with a scleral flap be performed with an implanted seton as the procedure of choice. If the eye is relatively quiet and has some visual reserve but an exceedingly high and intractable intraocular pressure, it is advisable to use either the carbon dioxide laser trabeculostomy procedure or the carbon dioxide laser trabeculo-sclerostomy operation as described. These procedures are being further refined, but the results of this investigation suggest that these procedures can be utilized judiciously, and should prove useful, particularly in those eyes with advanced neovascular glaucoma with useful vision still remaining.