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PubMed1992

Ultrasound biomicroscopy in plateau iris syndrome.

Ultrasound biomicroscopy is a new technique that uses high-frequency ultrasound (50 to 100 MHz) to produce images of the entire anterior segment at high resolution (20 to 50 microns). The iridocorneal angle, iris, ciliary body, and posterior chamber can be imaged in detail and the dimensions and anatomic relationships of these structures determined. Plateau iris syndrome is a condition in which the angle remains appositionally closed or occludable after iridectomy for angle-closure glaucoma. How the iris remains in a position that allows it to occlude the angle has been uncertain. We performed ultrasound biomicroscopy eye examinations on eight patients with clinically diagnosed plateau iris syndrome. In all the patients, ciliary processes were situated anteriorly compared to the position in normal subjects and in patients with angle closure caused by pupillary block. The ciliary processes provide structural support beneath the peripheral iris, preventing the iris root from falling away from the trabecular meshwork after iridectomy.

Anterior Eye Segment↗
PubMed1998

Quantification of aqueous melanin granules in primary pigment dispersion syndrome.

PURPOSE: Aqueous melanin granules are essential in the pathogenesis of pigment dispersion syndrome and pigmentary glaucoma. We quantified aqueous melanin granules with the laser flare-cell meter in patients with pigment dispersion syndrome, assessed the measurement reproducibility, and correlated the numbers with clinical findings. METHODS: Aqueous melanin granules were counted by means of the cell count mode of the laser flare-cell meter (KOWA FC-1000; Kowa, Tokyo, Japan) in 42 eyes of 21 patients with primary pigment dispersion syndrome under three conditions (undilated pupils, dilated pupils, after exercise). The reproducibility of the measurements was determined with the intraclass correlation coefficient. A control group of 40 age- and sex-matched eyes was also examined after pupillary dilation. The results were correlated with biomicroscopic findings in eyes with pigment dispersion syndrome (retrocorneal Krukenberg spindle, iris transillumination, pigmentation of trabecular meshwork). RESULTS: Numerous aqueous melanin granules were detected in eyes with pigment dispersion syndrome (mean, 2.9 +/- 3.7 granules/0.075 mm3) but only small numbers were counted in normal eyes (0.2 +/- 0.3, P < .001). Medical pupil dilation caused an additional increase of aqueous melanin granules in pigment dispersion syndrome (6.3 +/- 5.3, P < .001), but not undilated exercise (climbing stairs) (2.9 +/- 3.7, P > .5). The reproducibility of the measurements was very high (intraclass coefficient >0.92). The number of melanin granules correlated with the degree of Krukenberg spindle (r = .61, P = .004) and with iris transillumination (r = .69, P = .001). CONCLUSIONS: Quantification of aqueous melanin granules yields reproducible results and shows increased numbers in pigment dispersion syndrome, especially after pupillary dilation. Aqueous melanin granule quantification may be useful for evaluating eyes with pigment dispersion syndrome and for assessing treatment effects.

Adult↗
PubMed2004

Intraocular pressure spike after YAG iridotomy in patients with pigment dispersion.

BACKGROUND: The role of laser peripheral iridotomy to break a suspected reverse pupil block in the long-term control of pigment dispersion is promising, but the usefulness of this procedure has not been completely established. The author examined whether patients with pigment dispersion are at higher risk for an intraocular pressure (IOP) spike after laser peripheral iridotomy due to possible compromise of trabecular meshwork function, compared with patients undergoing prophylactic peripheral iridotomy for an occludable angle. METHODS: Data were collected prospectively on the first eye of 87 patients with occludable angles and 13 patients with pigment dispersion treated with peripheral laser iridotomy between November 1995 and October 1996 at the glaucoma service of a university-affiliated hospital in Toronto. All patients received one drop of 0.5% apraclonidine before the procedure. IOP was measured before and 1 and 24 hours after the procedure. RESULTS: There was no difference between the two groups in the distribution of right vs. left eyes, sex, race, the mean total energy required to produce a patent iridotomy, the mean number of medications used or the mean IOP before the procedure. The patients with pigment dispersion were significantly younger than those with occludable angles (mean age [and standard deviation (SD)] 40.5 [9.45] years vs. 66.4 [10.78] years) (p < 0.001). There was no difference between the two groups in mean IOP at 1 hour or at 24 hours. Twenty-nine patients (33%) in the occludable angle group and seven (54%) in the pigment dispersion group had an IOP spike greater than 2 mm Hg after the procedure (p = 0.001). Among these patients, the mean IOP (36.4 [SD 10.83] mm Hg vs. 30.3 [SD 7.04] mm Hg, p = 0.05) and the mean rise in IOP (14.0 [SD 10.63] mm Hg vs. 8.7 [SD 4.73] mm Hg, p = 0.04) were significantly higher in those with pigment dispersion than in those with occludable angles. Among the patients who used antiglaucoma medications before the procedure or had a prelaser IOP level greater than 22 mm Hg, those with pigment dispersion were more likely than those with occludable angles to have an IOP spike at 1 hour (p < or = 0.005). INTERPRETATION: Patients with pigment dispersion undergoing iridotomy to break a reverse pupil block should be carefully assessed after the procedure, as significant pressure spikes requiring treatment may occur.

Aged↗
PubMed2003

Role of aquaporin water channels in eye function.

The aquaporins (AQPs) are a family of more than 10 homologous water transporting proteins expressed in many mammalian epithelia and endothelia. At least five AQPs are expressed in the eye: AQP0 (MIP) in lens fiber, AQP1 in cornea endothelium, ciliary and lens epithelia and trabecular meshwork, AQP3 in conjunctiva, AQP4 in ciliary epithelium and retinal Müller cells, and AQP5 in corneal and lacrimal gland epithelia. This cell-specific expression pattern suggests involvement of AQPs in corneal and lens transparency, intraocular pressure (IOP) regulation, retinal signal transduction, and tear secretion. Indeed, humans with mutant AQP0 develop cataracts. Mice lacking AQP1 have reduced IOP and impaired corneal transparency after swelling, and mice lacking AQP4 have reduced light-evoked potentials by electroretinography. There is evidence for impaired cellular processing of AQP5 in lacrimal glands of humans with Sjogren's syndrome. AQPs facilitate fluid secretion and absorption in the eye, and hence are involved in the regulation of pressure, volume and tissue hydration. Pharmacological alteration of AQP function may provide a new approach for therapy of glaucoma, corneal edema, and other diseases of the eye associated with abnormalities in IOP or tissue hydration.

Animals↗
PubMed1987

Effect of topical pergolide on aqueous dynamics in normal and glaucomatous monkeys.

The effects of pergolide mesylate, an ergoline derivative, were studied on intraocular pressure (IOP), outflow facility, aqueous humor flow, and pupil size in monkeys. Unilateral topical administration of two 20-microliters drops of 0.1% pergolide significantly lowered IOP in the treated- and contralateral eye in both normal- and glaucomatous monkeys. In 12 normal monkeys, the baseline IOP of 18.3 +/- 0.4 mmHg [mean +/- S.E.(M.)] was maximally reduced to 14.4 +/- 0.7 mmHg in the treated eye (P less than 0.001) and 14.6 +/- 0.6 mmHg in the contralateral eye (P less than 0.001) at 2 hr after drug administration. In 10 monkeys made bilaterally glaucomatous by argon laser treatment of the trabecular meshwork, the baseline IOP of 33.9 +/- 3.0 mmHg [mean +/- S.E.(M.)] in the treated eyes and 31.7 +/- 3.3 mmHg in the untreated eyes maximally decreased to 23.9 +/- 2.2 mmHg (P less than 0.05) and 26.2 +/- 3.3 mmHg (P less than 0.005), respectively, at 5 hr. No significant change (P greater than 0.7) in outflow facility occurred in either eye of 11 normal monkeys 2 hr after unilateral 0.1% pergolide treatment. In six normal monkeys, the baseline aqueous humor flow of 1.58 +/- 0.20 microliter min-1 in treated eyes and 1.44 +/- 0.18 microliter min-1 in untreated eyes was reduced to 0.92 +/- 0.08 microliter min-1 (P less than 0.02) and 1.09 +/- 0.11 microliter min-1 (P greater than 0.10), respectively, from 0.5- to 3.5 hr after drug administration. A mydriatic response was observed in both eyes after unilateral treatment from 1- to 2 hr in eight normal monkeys. By the third day of treatment, bilateral twice a day 0.1% pergolide drops in eight glaucomatous monkey eyes no longer significantly (P greater than 0.05) decreased IOP.

Administration, Topical↗
PubMed1987

Non-additivity of maximal pilocarpine and cytochalasin effects on outflow facility.

Living cynomolgus monkeys received intracameral infusions of pilocarpine HCI (P)1 mg ml-1, followed by P + cytochalasin B (CB) 50 microgram ml-1; total outflow facility, measured by two-level constant pressure perfusion, tripled after P alone and then remained stable when CB was added. Other eyes received CB 25 micrograms ml-1 or 50 micrograms ml-1, followed by CB + P1 mg ml-1; facility quadrupled to sextupled after CB, but tended to decrease from those levels, although it remained above baseline, after P was added. The facility decrease accompanying the addition of P after CB might have related to the longer CB exposure, rather than to a specific P effect. These data indicate that despite different mechanisms of action and primary attack points on the outflow apparatus, near- or supramaximal P and CB doses are not additive, and are indeed mutually pre-emptive, in their facility increasing effect. These findings have implications in terms of trabecular-meshwork biophysics, fluid mechanics, and their pharmacological manipulation.

Animals↗
PubMed1988

The innervation of the rabbit's anterior eye segment: a retrograde tracing study.

The differential innervation of the distinct elements of the anterior segment of the rabbit eye, i.e. cornea, conjunctiva, ciliary body, iris, and trabecular meshwork, was studied using horseradish peroxidase-wheatgerm agglutinin (HRP-WGA) as a tracer. HRP-WGA was injected into the anterior chamber, the conjunctiva, or the cornea, and the animals were killed after 6 to 96 hr. The HRP-WGA localization was studied at the light and electron microscopic level. Injection into the anterior chamber led to an ubiquitous spread of the tracer in all elements of the anterior segment, resulting in a consistent retrograde labelling of neurons in the trigeminal (sensory), superior cervical (sympathetic) and ciliary (parasympathetic) ganglion. Neurons in the proximal part of the pterygopalatine ganglion (parasympathetic) were labelled only when the injected tracer was present in the conjunctiva. Varying survival times after corneal injection were used to establish restricted corneal uptake. Up to 16 hr after corneal injection, HRP-WGA was limited to the cornea and led to the exclusive labelling of neurons in the trigeminal ganglion, indicating that the central cornea has an almost exclusive sensory innervation. The trigeminal sensory neurons projecting to the cornea were restricted to a small antero-medial part of the trigeminal ganglion. Electron microscopy revealed four different cell types in the trigeminal ganglion. However, distinct elements of the anterior segment did not project to specific cell types.

Animals↗
PubMed1988

Signs of early damage in glaucomatous monkey eyes: low spatial frequency losses in the pattern ERG and VEP.

Experimental glaucoma was created in one eye of three cynomolgus monkeys by argon laser application to the mid-trabecular meshwork. Simultaneous pattern electroretinograms (PERG) and pattern visual evoked potentials (PVEP) were measured in both control and glaucoma eyes to spatial frequencies of 0.5, 1.25, 2.5, and 3.5 cpd which were counterphase modulated at 6 Hz. The transient flash electroretinogram was also measured. While normal flash electroretinograms were recorded in all eyes both before and after the unilateral production of elevated intraocular pressure (IOP), reductions in PERG and PVEP amplitude were seen in the eyes with glaucoma as early as two weeks following a sustained increase of IOP, despite the absence of cupping of the optic nervehead judged by ophthalmoscopic examination and analysis of photograph by two observers. Optic nervehead abnormalities occurred subsequently. In glaucomatous monkey eyes, the earliest PERG and PVEP changes were most evident with lower spatial frequencies of stimulation. Our data suggest that the optimal stimulus parameters for the detection of early glaucoma are low spatial frequency patterns presented at a rapid rate of temporal modulation.

Animals↗
PubMedDate not supplied

A clinical evaluation of uveitis-associated secondary glaucoma.

PURPOSE: To investigate the clinical features of secondary glaucoma associated with uveitis. METHODS: The subjects of the study were 1,099 patients with uveitis (1,604 eyes) treated at the Miyata Eye Hospital, Miyakonojo, Miyazaki, between October 1974 and January 2000. The intraocular pressure (IOP) and clinical data were analyzed retrospectively. Secondary glaucoma was diagnosed in the patients when IOP was higher than 21 mm Hg at two consecutive visits and they needed treatment with medication to control the high IOP. RESULTS: Secondary glaucoma was found in 293 eyes (18.3%) of 217 patients (19.7%) among the uveitis patients. The clinical entity with the highest incidence of secondary glaucoma was Posner-Schlossman syndrome in 100%, followed by sarcoidosis in 34.1%, herpetic anterior uveitis in 30.4%, Behçet's disease in 20.8%, human leukocyte antigen-B27-related acute anterior uveitis in 20.0%, Vogt-Koyanagi-Harada's disease in 16.4%, and human T-lymphotropic virus type 1 uveitis in 16.2%. Among these 293 eyes with secondary glaucoma, the majority (72%) had active anterior uveitis at the time of high IOP. Only 7.5% of the secondary glaucoma eyes had peripheral anterior synechia wider than 180 degrees of the trabecular meshwork. Steroid-induced glaucoma was found in only 8.9% of the secondary glaucoma eyes. Surgical therapy, mainly trabeculectomy with anti-metabolites, was performed in 38 eyes and the post-surgical IOP was controlled under 20 mm Hg in 34 eyes. Despite the medical and surgical therapy for secondary glaucoma, visual field defect was found in 39% of the secondary glaucoma eyes. CONCLUSIONS: The incidence of secondary glaucoma in the 1,604 eyes with uveitis was 18.3%, but it differed depending upon the clinical entity of the uveitis. The evaluation and the management of IOP are very important in the treatment of patients with uveitis, in addition to the management of intraocular inflammation.

Adult↗
PubMedDate not supplied

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.

Angiography↗
PubMed2003

Targeting outflow facility in glaucoma management.

Glaucoma is often characterized by decreased pressure-sensitive aqueous outflow through the trabecular meshwork. This defect in pressure-sensitive aqueous outflow is evident from the low tonographic facility of outflow ("C") measured in many patients. The impairment in outflow facility causes the high intraocular pressure (IOP) and large diurnal IOP fluctuations often found in glaucoma. Because large diurnal IOP fluctuations have been shown to be a risk factor for glaucomatous progression, IOP-lowering therapy should aim to achieve a low, stable IOP. Pressure-sensitive aqueous outflow helps prevent and dampen pressure spikes; thus, drugs that enhance outflow facility, in particular, may stabilize as well as lower IOP. Outflow facility is an attractive target for glaucoma treatment because enhancing outflow facility tends to restore the self-regulating tendency of IOP. Older drugs such as the cholinergic pilocarpine and the catecholamine epinephrine act primarily by improving outflow facility. This action is also important for the recently introduced prostamide, bimatoprost, as well as for the prostaglandin prodrug, latanoprost. Realization of the importance of facility of outflow in lowering and stabilizing IOP will stimulate additional research into the mechanism of action of ocular hypotensive agents and will help optimize the medical treatment of glaucoma.

Antihypertensive Agents↗
PubMedDate not supplied

Melanocytoma of the iris with rapidly developing secondary glaucoma.

A 28-year-old woman with an upper nasal iris mass developed secondary glaucoma within a few months of presentation. Although the elevated pressure responded to medical therapy, in the interests of a definitive diagnosis as well as prevention of damage to the trabecular meshwork, surgical management was decided upon. Tumor excision was performed through a double-layered sclerolimbal flap. Light and electron microscopic examinations of the tissue revealed a partially necrotic iris melanocytoma. Six months after surgery, the patient's best corrected visual acuity was 20/30 in the affected eye, and the intraocular pressure was 21 mmHg without therapy. The lens remained clear. The differential diagnosis and management of melanocytomas, particularly the role of biopsy, are discussed.

Adult↗
PubMed2000

Angle-closure glaucoma in an urban population in southern India. The Andhra Pradesh eye disease study.

OBJECTIVE: To assess the prevalence and features of angle-closure glaucoma (ACG) in an urban population in southern India. DESIGN: A population-based, cross-sectional study. PARTICIPANTS: A total of 2522 (85.4% of those eligible) persons of all ages, including 1399 persons 30 years of age or older, from 24 clusters representative of the population of Hyderabad city. TESTING: The participants underwent an interview and detailed eye examination that included logarithm of minimum angle of resolution visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, and gonioscopy; pupil dilatation and stereoscopic fundus evaluation was performed if the risk of angle-closure as a result of dilatation was not believed to be imminent. Humphrey threshold 24-2 visual fields (Humphrey Instruments Inc., San Leandro, CA) were performed when indicated by standardized criteria for disc damage or if intraocular pressure (IOP) was 22 mmHg or more. MAIN OUTCOME MEASURES: An occludable angle was defined as pigmented posterior trabecular meshwork not visible by gonioscopy in three quarters or more of the angle circumference. Manifest primary angle-closure glaucoma (PACG) was defined as IOP of 22 mmHg or more or glaucomatous optic disc damage with visual field loss in the presence of an occludable angle. An IOP of 22 mmHg or more or glaucomatous optic disc damage in the presence of an occludable angle secondary to an obvious cause was defined as secondary ACG. RESULTS: Manifest PACG and occludable angles without ACG were present in 12 and 24 participants, respectively, with age- and gender-adjusted prevalence (95% confidence interval [CI]) of 0.71% (0.34%-1.31%) and 1.41% (0.73%-2.09%) in participants 30 years of age or older, and 1.08% (0.36%-1.80%) and 2.21% (1.15%-3.27%) in participants 40 years of age or older, respectively. With multivariate analysis, the prevalence of these two conditions considered together increased significantly with age (P < 0.001); although not statistically significant, these were more common in females (odds ratio 1.70; 95% CI, 0.82-3.54) and in those belonging to lower socioeconomic strata as compared with middle and upper strata (odds ratio, 1.82; 95% CI, 0.88-3.74). The odds of manifest PACG were higher in the presence of hyperopia of more than 2 diopters ([D]; odds ratio, 3.69; 95% CI, 0.89-15.2). Only four of 12 participants (33.3%) with manifest PACG had been previously diagnosed, and one of 12 (8.3%) had peripheral iridotomy performed previously. Manifest PACG had caused blindness in one or both eyes in five of these 12 participants (41.7%); best-corrected distance visual acuity less than 20/400 in one or both eyes in four patients, and acuity less than 20/200 in one eye in another patient. Most (83.3%) of those with manifest PACG could be classified as having chronic form of the disease. We may have underestimated manifest PACG because visual fields were per- formed only on those with clinical suspicion of optic disc damage. Secondary ACG was present in two participants. CONCLUSIONS: The prevalence of PACG in this urban population in southern India is close to that reported recently in a Mongolian population. A large proportion of the PACG in this population was undiagnosed and untreated. Because visual loss resulting from PACG is potentially preventable if peripheral iridotomy or iridectomy is performed in the early stage, strategies for early detection of PACG could reduce the high risk of blindness resulting from PACG seen in this urban population in India.

Adolescent↗
PubMed2002

Diffuse iris melanoma: a report of 25 cases.

BACKGROUND: Diffuse iris melanoma is a rare variant of iris melanoma that has a flat growth pattern and often presents as unilateral hyperchromic heterochromia and glaucoma. There have been no large clinical reports of diffuse iris melanoma. DESIGN: Single-center retrospective case series. PARTICIPANTS: Twenty-five consecutive patients with diffuse iris melanoma. METHODS: A review of the clinical features, management, histopathologic analysis, and prognosis was performed. MAIN OUTCOME MEASURES: Clinical features, histopathologic features, management, and prognosis. RESULTS: At the time of diagnosis, the mean patient age was 49 years. The initial complaint was unilateral darker eye color in 13 cases (52%) and blurred vision in 6 (24%). Six patients (24%) were symptom free. On presentation elsewhere, the initial diagnosis was iris melanoma or nevus in 11 cases (44%) and glaucoma in 14 (56%), 8 (32%) of whom had prior laser or surgical treatment for glaucoma. The 25 patients were observed for a mean of 30 months before the diagnosis of melanoma was suspected and referral to our center for evaluation. The mean intraocular pressure at referral was 36 mmHg, and the mean number of clock hours involved by tumor was 11. Heterochromia iridis was present in all 25 cases (100%), corectopia in 23 (92%), and ectropion iridis in 21 (84%). Associated findings included unilateral cataract in 8 (32%), a prominent episcleral (sentinel) vessel in 7 (28%), and anterior chamber inflammation in 5 (20%), and synechiae (anterior or posterior) in none. The tumor was managed by enucleation in 22 cases (88%) and by plaque brachytherapy in 3 (12%). Five cases (20%) were classified as spindle melanoma, 17 (68%) as mixed cell type, and 3 (12%) as epithelioid cell type. Therefore, histopathologic examination showed that 80% of cases contained epithelioid cells. All 22 enucleated cases were found to have tumor invasion in the trabecular meshwork. Tumor invasion of Schlemm's canal was found in 18 (82%), minor pars plicata in 12 (55%), and episclera in 7 cases (28%). Of seven cases with episcleral invasion, four underwent surgical treatment for glaucoma. Excluding one recent case, the patients were observed for a mean of 78 months. Liver metastasis developed in 3 cases (13%). CONCLUSIONS: Diffuse iris melanoma is a serious ocular condition that causes unilateral hyperchromic heterochromia and secondary glaucoma, often leading to a delay in diagnosis. Local invasion of adjacent ocular structures is common, and distant metastasis occurs in 13% of cases at mean follow-up of 78 months.

Adolescent↗
PubMed1979

A pharmacologist looks at medical treatment in glaucoma--in retrospect and in prospect.

The histochemical distribution of carbonic anhydrase activity in the ciliary processes is shown. There is a multiplicity of possible points of attack of carbonic anhydrase inhibitors, We do not know which sites are critically inhibited at clinical dosage. One primary mechanism of the therapeutic action of miotics is ciliary muscle contraction, but on prolonged treatment, subsensitivity of the muscle may shift emphasis to miotic inhibition of aqueous secretion by unknown mechanisms. The trabecular meshwork is a slow tissue living off the aqueous. Aqueous composition in chronic simple glaucoma should therefore be studied with a view to possible treatment of the sick meshwork.

Animals↗
PubMed1982

An unusual case of ocular involvement in primary systemic nonfamilial amyloidosis.

A case of primary amyloidosis with vitreous involvement was diagnosed by study of a specimen obtained by pars plana vitrectomy. Vitreous opacities had been interpreted clinically as a vitreous hemorrhage. Medical evaluation after study of the vitreous specimen failed to demonstrate evidence of amyloidosis, although postmortem examination 19 months later established the systemic diagnosis of nonfamilial systemic primary amyloidosis. Both eyes were obtained postmortem. Amyloid involvement of the vitreous, retina, and choroid was found. There was also amyloid deposition in the trabecular meshwork, although the intraocular pressure was normal. Amyloid was deposited along the anterior, pupillary, and posterior surfaces of the iris. The histochemistry, ultrastructure, and treatment of this condition are discussed.

Amyloid↗
PubMed1983

The contralateral eye in the iridocorneal endothelial (ICE) syndrome.

Examination of six cases of iridocorneal endothelial (ICE) syndrome revealed that all the patients had subclinical abnormalities in the fellow eye. Of the six, four patients had iris transillumination, four patients had significantly decreased outflow facility but without elevation of intraocular pressure, and all patients had corneal endothelial changes as noted by specular microscopy. The asymmetric rather than unilateral involvement and the similar histopathology to posterior polymorphous dystrophy suggested that these two diseases may share a common pathogenesis. The occurrence of features of Rieger's syndrome and Axenfeld's anomaly in association with posterior polymorphous dystrophy suggested the hypothesis that all these diseases may be characterized by abnormalities of tissues derived from neural crest cells. A unifying hypothesis is presented to explain this group of diseases involving the endothelial cells lining the anterior chamber, namely corneal and trabecular meshwork endothelium, anterior iris stroma and iris melanophores.

Adult↗
PubMed1987

Distribution of tissue plasminogen activator in human and monkey eyes. An immunohistochemical study.

The authors examined various structures of human and rhesus monkey eyes for the presence of tissue plasminogen activator (t-PA) by using the peroxidase-antiperoxidase immunohistochemical technique with a monoclonal antibody specific for human t-PA. Positive staining for t-PA was observed both intracellularly and in the extracellular matrix of many tissues in both species. The tissues which stained intensely for t-PA included the corneal endothelium, corneal epithelium, trabecular meshwork, lens epithelium, peripheral vitreous, uveal tract, inner retina, and all vascular endothelia. The apparent minor difference in staining intensity between human and monkey eyes may be related to the time-dependent degradation of t-PA, to variations in the tissue content of t-PA, or to the difference in animal species. The discussion includes a consideration of the fibrinolytic activity of t-PA and of its emerging role in the destructive remodeling of the extracellular matrix in various ocular structures.

Animals↗