A case report of neovascular glaucoma due to carotid artery occlusive disease--diagnosis of neovascular glaucoma and histological characteristics

PURPOSE: The methods of diagnosing neovascular glaucoma were evaluated in a case with carotid artery occlusive disease. A trabeculectomy specimen taken from this patient was examined histologically to find the characteristic picture of this slowly progressive neovascular glaucoma. MATERIALS AND METHODS: The left eye of a 48-year old man with neovascular glaucoma due to carotid artery occlusive disease had been previously diagnosed as uveitis with ocular hypertension. His left eye was examined by fluorescein fundus and gonioangiography. Trabeculectomy was performed because of uncontrolled intraocular pressure and the trabeculectomy specimen was examined histologically including immunohistochemistry with antibodies against von Willebrand factor antigen. RESULTS: The characteristic picture of fluorescein fundus angiography was filling delay in the choroid and stained walls of the retinal arteries and veins. Fluorescein gonioangiography using a fundus camera clearly demonstrated new vessels in the pupil and angle with intense fluorescein leak in spite of faint neovascularization in those areas when observed by slit lamp with gonioscopy. Histological examination of the trabeculectomy specimen revealed proliferation of new vessels in the spaces of the trabecular meshwork and focal occlusion of Schlemm's canal. CONCLUSION: Fluorescein fundus angiography and gonioangiography by fundus camera is very useful for diagnosis of neovascular glaucoma due to carotid artery occlusive disease. Neovascular proliferation in the trabecular meshwork with slight of peripheral anterior synechia and focal occlusion of Schlemm's canal may be peculiar to such slowly progressive neovascular glaucoma.     

A Case Report of Neovascular Glaucoma Due to Carotid Artery Occlusive Disease. Diagnosis of Neovascular Glaucoma and Histological Characteristics

Purpose: The methods of diagnosing neovascular glaucoma were evaluated in a case with carotid artery occlusive disease. A trabeculectomy specimen taken from this patient was examined histologically to find the characteristic picture of this slowly progressive neovascular glaucoma.Materials and Methods: The left eye of a 48-year old man with neovascular glaucoma due to carotid artery occlusive disease had been previously diagnosed as uveitis with ocular hypertension. His left eye was examined by fluorescein fundus and gonioangiography. Trabeculectomy was performed because of uncontrolled intraocular pressure and the trabeculectomy specimen was examined histologically including immunohistochemistry with antibodies against von Willebrand factor antigen.Results: The characteristic picture of fluorescein fundus angiography was filling delay in the choroid and stained walls of the retinal arteries and veins. Fluorescein gonioangiography using a fundus camera clearly demonstrated new vessels in the pupil and angle with intense fluorescein leak in spite of faint neovascularization in those areas when observed by slit lamp with gonioscopy. Histological examination of the trabeculectomy specimen revealed proliferation of new vessels in the spaces of the trabecular meshwork and focal occlusion of Schlemm's canal.Conclusion: Fluorescein fundus angiography and gonioangiography by fundus camera is very useful for diagnosis of neovascular glaucoma due to carotid artery occlusive disease. Neovascular proliferation in the trabecular meshwork with slight of peripheral anterior synechia and focal occlusion of Schlemm's canal may be peculiar to such slowly progressive neovascular glaucoma.     

A case of glaucoma with choroidal hemangioma managed by nonpenetrating trabeculectomy

BACKGROUND: Nonpenetrating trabeculectomy was used in a patient with glaucoma complicated by diffuse choroidal hemangioma. CASE: A 12-year-old boy suffered from glaucoma with choroidal hemangioma in the left eye. Intraocular pressure was 28 mm Hg and visual acuity was 0.04. Nonpenetrating trabeculectomy was then performed. OBSERVATIONS: Postoperative intraocular pressure was controlled at around 15 mm Hg with pilocarpine hydrochloride eye drops. Visual acuity and visual field were preserved over 19 months after the operation. CONCLUSIONS: An increase in aqueous outflow resistance was considered to be the major mechanism in the rise in intraocular pressure, based on distinct dilatation and tortuosity of the episcleral blood vessels and congestion of Schlemm's canal. Therefore, construction of aqueous drainage by nonpenetrating trabeculectomy was effective. Retaining the trabecular meshwork was also considered effective in controlling complications such as choroidal hemorrhage and postoperative flat anterior chamber.     

Ab interno trabeculectomy: ultrastructural evidence and early tissue response in a human eye

PURPOSE: To report the results of ultrastructural analysis of the postoperative effects of ab interno trabeculectomy in a human eye. SETTING: Department of Ophthalmology, Palmanova Hospital, Palmanova, Udine, Italy. METHODS: A 60-year-old woman with cataract and glaucoma had enucleation for a choroidal melanoma 10 days after ab interno trabeculectomy combined with phacoemulsification. A second ab interno trabeculectomy was performed after enucleation to evaluate the outcomes of the previous trabeculectomy. Light and transmission electron microscopy analyses were performed on samples excised from areas (1) not subjected to a procedure (control samples), (2) that had ab interno trabeculectomy before enucleation, and (3) that had ab interno trabeculectomy immediately after enucleation. RESULTS: Control samples showed normal trabecular features. Semithin sections of all ab interno trabeculectomy samples showed full-thickness removal of trabeculum segments, with Schlemm's canal lumen opening into the anterior chamber and apparent preservation of the adjacent structures. On ultrathin sections of samples that had ab interno trabeculectomy before enucleation, the endothelium lining the outer wall of Schlemm's canal and other angle components showed intact ultrastructural features. In trabecular beams that were not removed, the extracellular matrix appeared to have maintained its fine texture and was free of activated fibroblasts or leucocyte infiltrates. CONCLUSIONS: Observations confirm that ab interno trabeculectomy causes direct communication between Schlemm's canal lumen and the anterior chamber in vivo and immediately after enucleation during the early postoperative period. The absence of an evident inflammatory reaction in the examined case should be considered with caution because of possible tumor-induced immune suppression.     

Histopathological study of a case with glaucoma due to Sturge-Weber syndrome]

PURPOSE: To investigate by histopathology the cause of secondary glaucoma due to Sturge-Weber syndrome. CASE: A 10-year-old boy with Sturge-Weber syndrome and glaucoma in the right eye is reported. Trabeculectomy was performed because of uncontrolled intraocular pressure and the trabeculectomy specimen was examined histologically by both light and electron microscopy. RESULTS: Histological examination of the trabeculectomy specimen showed the ciliary muscle dislocated anteriorly and there was no Schlemm's canal. The spaces in juxtacanalicular connective tissue(JCT) were replaced by vascular structures and connective tissue. There were two kinds of vascular structures, one where the endothelium was surrounded by pericytes and the other where it was not surrounded by pericytes. CONCLUSIONS: Developmental abnormalities of Schlemm's canal and JCT may have caused glaucoma in this case. These observations suggested that development of both mesoderm and neural crest might be involved in the pathogenesis of glaucoma due to Sturge-Weber syndrome.     

A case of Rubinstein-Taybi syndrome suspected with goniodysgenetic glaucoma

We reported a case of Rubinstein-Taybi syndrome suspected in association with goniodysgenetic glaucoma, and studied using light and electron microscopy the anterior chamber angle tissues obtained surgically by trabeculectomy. The patient was 31-year old male, who had a systemic appearance of Rubinstein-Taybi syndrome with dwarfism, mental retardation, antimongoloid slant, flat-broad based thumbs, low set ears, high arched plate except for whorl of dermatographism. In addition to these malformations, goniodysgenetic glaucoma was also present which is characterized by underdevelopment of the angle recess and invisible ciliary body band in gonioscopic examination. The histopathological studies of the specimens revealed the presence of a compact tissue filled with a large amount of collagen fibers with few cells in the juxta-canalicular tissue of Schlemm's canal. There were 3 to 4 layers of trabecular sheets of corneoscleral meshwork at the anterior chamber side of the compact tissue. We conclude that the presence of the compact tissue under Schlemm's canal represents goniodysgenesis, underdevelopment of the trabecular meshwork, which is the primary cause of the glaucoma in this case.     

Iris vessel involvement in iris-nevus syndrome

PURPOSE: To report a case of iris-nevus syndrome accompanied by disruption of the blood-aqueous barrier in the iris which was confirmed angiographically and histopathologically. CASE: The patient was a 39-year-old woman. She noticed blurred vision in the left eye which was diagnosed as left glaucoma. Specular microscopy revealed low endothelial cell density in the left cornea. The left iris showed atrophy with clusters of nodular iris nevus and distorted pupil. The left iridocorneal angle was closed with peripheral anterior synechia. FINDINGS: Indocyanine green iris angiography revealed more vessels on the surface of the left iris than on the right. In fluorescein iris angiography, the dye leaked from the iris vessels in areas where the iris showed advanced atrophy. The trabecular tissue obtained by trabeculectomy from the patient's left eye showed histopathologically a lining of corneal endothelial cells on the surface of the iris. The density of the vessels was high in the iris stroma. Some cells covering the vessel wall showed degeneration with opening of the zonula occludens. Schlemm's canal had narrowed lumina, and the intertrabecular spaces were closed. CONCLUSION: Disruption of the blood-aqueous barrier may occur in iris-nevus syndrome.     

Morphology of the trabecular meshwork three years after Erbium:YAG laser trabecular ablation.

Laser trabecular ablation (LTA) is an abinterno approach with the purpose to improve outflow facility by removing trabecular tissue and open Schlemm's canal. In a blind eye with secondary glaucoma following silicone oil surgery, Erbium:YAG LTA had been performed applying 12 neighboring single laser pulses (5-7 mJ pulse energy, 200 micros pulse duration) to the trabecular meshwork. Enucleation was performed three years after the procedure that did not achieve pressure control. Light-microscopy revealed neither marked scarring nor endothelial proliferation in the treated trabecular meshwork. However, most of the recognizable ablation craters failed to open Schlemm's canal. Although limited scar formation within the trabecular meshwork after LTA is a promising aspect, the present technique of Er:YAG LTA still needs technical and surgical improvements to guarantee reliable and reproducible openings of Schlemm's canal.     

Pigment glaucoma. Scanning-electronmicroscopic findings. (author's transl)]

In case of a patient suffering from pigment glaucoma trabeculectomy was performed on both eyes. In one trabecular section the outer wall of Schlemm's canal, and in the other the trabecular framework were investigated by scanning-electronmicroscopy. The intertrabecular spaces were largely blocked by pigment granula, which, in some places, were stored in the clump cells of the iris. Even the outer wall of Schlemm's canal was dotted with pigment granula. The scanning-electronmicroscopic findings revealed the pigmental drainage blocking of the aqueous humour and explained the acute pressure rise in the pigment glaucoma with wide iridocorneal angle by an acute obstruction of the already largely blocked intertrabecular spaces.     

How does nonpenetrating glaucoma surgery work? Aqueous outflow resistance and glaucoma surgery

Histologic, experimental, and theoretical studies of the aqueous outflow pathways point toward the juxtacanalicular region and inner wall of Schlemm's canal as the likely site of aqueous outflow resistance in the normal eye. At least 50% of the aqueous outflow resistance in the normal eye and the bulk of the pathologically increased resistance in the glaucomatous eye resides in the trabecular meshwork and the inner wall of Schlemm's canal. The uveoscleral, or uveovortex, pathway, which accounts for perhaps 10% of the aqueous drainage in the healthy aged human eye, can become a major accessory route for aqueous drainage after pharmacologic treatment. Surgeries designed to incise or remove the abnormal trabecular meshwork of glaucoma address the pathologic problem of the disease. Surgeries that unroof Schlemm's canal or expand the canal, such as viscocanalostomy, probably cause inadvertent ruptures of the inner wall and juxtacanalicular tissue, thus relieving the abnormal outflow resistance of glaucoma. This review is a summary of current thought on the pathophysiology of aqueous outflow resistance in glaucoma and, in light of this, provides an interpretation of the mechanism of pressure reduction created by these new surgeries.     

The changing conceptual basis of trabeculectomy: a review of past and current surgical techniques

The original intent of glaucoma surgery was to allow aqueous humor to exit more easily either through the sclera or into the suprachoroidal space. The former came to be called, generically, a glaucoma filtering procedure. As this surgery evolved, some explored the concept of lowering pressure without producing a hole in the sclera, with its resultant "filtering bleb." For example, Cairns hoped that cutting open the edges of Schlemm's canal would allow aqueous to leave without producing a filtering bleb; however, it became apparent that Cairns's "trabeculectomy" only worked when a filtering bleb developed. The goal of today's trabeculectomy is the creation of a longlasting transscleral fistula. In fact, trabeculectomy is a misnomer as excision of trabecular meshwork is unimportant. Frequently, the tissue excised to create a trans-scleral fistula is sclera, cornea, or both. The current trabeculectomy is really a guarded sclerokeratectomy. Newer techniques hope to increase aqueous outflow through Schlemm's canal to avoid complications associated with subconjunctival filtering blebs. Non-penetrating glaucoma surgeries (deep sclerectomy, viscocanalostomy) and ab interno trabecular surgery attempt to lower intraocular pressure with bleb-less procedures. We describe the recent evolution of glaucoma surgery, particularly the idea that intraocular pressure may be lowered satisfactorily without creating a filtering bleb.     

Ab interno trabeculectomy: development of a novel device (Trabectome) and surgery for open-angle glaucoma

PURPOSE: To design an instrument to selectively remove trabecular meshwork and Schlemm's canal inner wall (SCIW), and demonstrate its effectiveness by histologic analysis of treated cadaveric human tissue. METHODS: The design parameters of the instrument were the ability to permanently remove a segment of trabecular meshwork and Schlemm's canal inner wall without causing damage to surrounding tissue, and to allow use with standard anterior segment surgical techniques and equipment via an ab interno approach. Treatment was applied to 20 segments of human corneoscleral rims. The treated areas were examined using a confocal microscope and compared with matching areas in untreated controls and simulated goniotomy. RESULTS: The resultant instrument system surgically removes the trabecular meshwork and Schlemm's canal inner wall from an anterior chamber approach. It consists of a disposable surgical handpiece with irrigation, aspiration, and electrocautery to focally ablate the target tissues. The attached console includes a high-frequency (550 KHz) electrosurgical generator and irrigation/aspiration controlled by a foot pedal. Histologic examination of specimens treated with the Trabectome displayed disruption of the trabecular meshwork and Schlemm's canal inner wall without damage to surrounding structures. The specimens treated by simulated goniotomy displayed significant damage to the outer wall of Schlemm's canal and the surrounding sclera. The controls showed no disruption or damage to any tissues. CONCLUSIONS: The Trabectome system is designed for performing trabeculectomy via an ab interno approach. It successfully removed sections of trabecular meshwork and Schlemm's canal inner wall with less injury to the adjacent tissue compared with goniotomy knife in vitro. Theoretically, this procedure should provide direct access of aqueous humor to Schlemm's canal.     

Comparison of the results of simultaneous trabeculectomy and cataract extraction with microscopic evaluation

The dependence of hydrodynamics on the topography of trabeculectomy performed simultaneously with cataract extraction was checked in 35 eyes with cataract and glaucoma. The eye was opened by a three-surface incision with a broad scleral flap. The specimen were examined in a microscope. In 21 eyes the whole trabeculum together with Schlemm's canal were excised, in 12 eyes the anterior band. In the specimen from 2 eyes no elements of the trabeculum could be found. The dependence of the regulation of the IOP on the geography of the trabeculectomy was established. Accepting the filtering mechanism of the trabeculectomy one may assume that the applied method of incision promotes the formation of the outflow++ ways of the aqueous in a high percentage of cases.     

Histopathological study of a case with glaucoma due to Sturge-Weber syndrome

PURPOSE: To investigate the cause of the secondary glaucoma in a case of Sturge-Weber syndrome by histopathology. CASE: A 10-year-old boy with Sturge-Weber syndrome and glaucoma in the right eye was studied. Trabeculectomy was performed because of uncontrolled intraocular pressure, and the trabeculectomy specimen was examined histologically by both light and electron microscopy. RESULTS: Histological examination of the trabeculectomy specimen showed that the ciliary muscle was dislocated anteriorly, and the Schlemm canal was not present. The spaces in the juxtacanalicular connective tissue (JCT) were replaced by vascular structures and connective tissue. There were two kinds of vascular structures: in one, the endothelium was surrounded by pericytes; and in the other, the endothelium was not surrounded by pericytes. CONCLUSIONS: Developmental abnormalities of the Schlemm canal and the JCT may have caused the glaucoma. These observations suggest that the developmental abnormalities of both the mesoderm and the neural crest might be involved in the pathogenesis of the glaucoma in cases of Sturge-Weber syndrome.     

微观直视下对房角结构阻滞部位与房水引流功能障碍的研究

通过110只原发性开角型青光眼的显微手术与一系列的检查观察,多数病例可以明确其房角结构的阻滞部位。其中单纯小梁网阻滞或单纯schlemm氏管阻滞都较少。S管腔与小梁网同时存在阻滞占大多数,特别晚期青光眼如此。当S管腔发生较广泛粘连而致严重阻滞时,其相应部位的小梁网与外集液管遭受相应的器质性阻滞而发生功能障碍。对小梁型、S管型、外集液管型青光眼的诊断要点,作了简要说明。     

Surgical landmarks in trabecular surgery.

Clinical and histologic studies in 40 eyes of 35 patients with chronic open-angle glaucoma or chronic angle-closure glaucoma operated by various types of "trabeculectomies" were assessed to evaluate whether success was correlated with the surgical approach or with the presence of trabecular tissue in the pathologic specimen. It was clearly demonstrated that it is not necessary to localize or enter Schlemm's canal in order to perform successful trabeculectomies; it is not necessary to operate posterior to the scleral spur; and it is not necessary to excise either Schlemm's canal or trabecular tissue to achieve success. In essence, trabeculectomies primarily function as fistulizing operations carried out under scleral flaps substituting a scleral-conjunctival barrier to aqueous flow rather than the conjunctival barrier alone provided by standard glaucoma operations. This greater obstruction explains the absence of shallow chambers, the reduced incidence of polycystic bleb formation and, perhaps, an avoidance of long-term complications that often result from these two factors.     

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.     

Physiology of aqueous humor outflow resistance: its relation to giant vacuoles

About 2% of the French population over the age of 40 suffers from open angle glaucoma, a disorder for which ocular hypertension is the main risk factor. Improving our understanding of primary open-angle glaucoma physiopathology has been an area of intense research for nearly a century. The main aqueous outflow system in the human eye includes the trabecular meshwork, Schlemm's canal, aqueous veins, and the episcleral veins. Schlemm's canal is bordered by endothelium cells, many of which contain giant vacuoles, structures that are sensitive to intraocular pressure and that therefore can act as markers of active outflow. Giant vacuoles are most often found near collector channels in normal eyes, probably in areas of low downstream pressure. In the glaucoma eye, determining where giant vacuoles form could help localize the site of pathological outflow resistance.