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PubMed1994

Invasive squamous cell carcinoma of the conjunctiva.

A 73-year-old man had been treated for a sore, red, left eye for 4 months before a clinical diagnosis of squamous cell carcinoma of the limbus was made. This diagnosis was confirmed on examination of a biopsy specimen, but after an initial surgical attempt to fully excise the tumor, there was clinical evidence of intraocular spread. An extensive corneoscleral resection and iridocyclectomy appeared to completely excise the tumor, as indicated by frozen section review. However, 1 year later, the patient re-presented with obvious residual squamous cell carcinoma of the iris and trabecular meshwork, well away from the original tumor site. Subsequent exenteration has resulted in a tumor-free patient for 1 year. Apparent surgical clearance of an extensive squamous cell carcinoma does not ensure total intraocular clearance of residual tumor, which may be remote from the original tumor site.

Aged↗

PubMed1977

Necrotic melanocytoma of iris with secondary glaucoma.

A 23-year-old white man had a pigmented iris tumor that was not enlarging; it produced satellite iris lesions, diffuse pigmentation of the trabecular meshwork, and secondary glaucoma. Although enucleation was initially recommended, we chose to remove only the primary lesion with a sector iridectomy. Histologically, the lesion proved to be a benign melanocytoma that had undergone extensive necrosis. Postoperatively, the satellite lesions, pigmentation in the angle, and glaucoma all resolved.

Adult↗

PubMed1991

Argon laser pretreatment 4 to 6 weeks before Nd:YAG laser iridotomy.

Argon laser pretreatment followed by Nd:YAG laser iridotomy 4 to 6 weeks later was performed in the right eye of 10 patients. Primary Nd:YAG laser iridotomy was performed in the left eye. Significantly more Nd:YAG laser energy was needed to produce an iridotomy in pretreated eyes (P less than .001). Pretreated eyes developed a significantly larger pigment epithelium defect around the iridotomy site and a greater degree of pigmentation of the inferior part of the trabecular meshwork 6 months following treatment. Argon laser pretreatment followed by Nd:YAG laser iridotomy 4 to 6 weeks later appears to offer no advantages over primary Nd:YAG laser iridotomy.

Aged↗

PubMed2000

Erbium-YAG laser-assisted preparation of deep sclerectomy.

BACKGROUND: Deep sclerectomy and viscocanalostomy are becoming more and more popular as non-penetrating filtering procedures. The purpose of the present study was to simplify the technique of this procedure and to reduce the rate of unintended perforations during the preparation of the deep lamella. METHODS: 20 enucleated porcine eyes were used. A superficial lamellar scleral flap with an area of 5x5 mm as for trabeculectomy was surgically prepared. Using a pulsed erbium:YAG laser the deep lamella (220 +/- 40 microm) with an area of 4x3 mm was removed. Ablation was performed with an energy of 40-100 mJ, a frequency of 1-10 Hz and a spot size of 500 microm and 1 mm (divergent beam). During the procedure the intraocular pressure was kept constant by continuous infusion. Finally the eyes were analyzed histologically. RESULTS: After initial trials it was possible to ablate the remaining deep corneoscleral lamella with the erbium:YAG laser without perforating into the anterior chamber. Starting with an energy of 70-85 mJ and a reduction to 40-60 mJ when reaching deeper layers, a spot size of 500 microm and a 10 Hz repetition rate gave the highest safety and efficiency in preparation. After a learning curve it was possible to preserve Descemet's membrane and intact trabecular meshwork in 10 consecutive operations as demonstrated by histology. CONCLUSION: Erbium:YAG laser-assisted deep sclerectomy offers an alternative to microsurgical preparation of the deep scleral lamella. The thermal damage is minimal (10-40 microm) and scarring may therefore not be stimulated.

Animals↗

PubMed1992

Recent pathogenic concepts of primary open angle glaucoma and soft glaucoma (POAG).

Loss of mainly field in POAG is due to Schnabel's cavernous atrophy of the axons at their scleral passage, built up by aligned stacks of glial collagen (IV and I) tissue plates, which contain capillaries. Organisation, size and structural surroundings encircle isolated or grouped axons not evenly distributed. The stereotype pattern of fieldloss linked to a characteristic optic nerve lesion suggests POAG be considered a N.O. disease as raised IOP may be only one of the risk factors. Are cavernous atrophy (loss of field) and the trabecular spaces narrowing (rise of IOP) both the result of the same pathogenic mechanism acting on the collagen fiber (IV and I) of the scleral coat, resp. lamina cribrosa (posterior segment) and trabecular meshwork (anterior segment)? If so, IOP-rise only worsens the condition as will do a hemodynamic energy crisis at the level of the axons. Interactive dominance at any of both levels may explain unexpected discrepancies between IOP and fieldloss. Considering "to treat or not to treat" accurate field loss predictability testing, urgent research topic, are discussed.

Anterior Chamber↗

PubMed1984

Histoplasma capsulatum in the eye.

The ocular pathologic findings in an immunosuppressed patient who died of disseminated histoplasmosis are described. Histoplasma capsulatum was found in large numbers within the endothelial cells of the choroid, in one area each of the ciliary body and trabecular meshwork. There was a minimal inflammatory response. No granulomas were noted. Previously reported cases of ocular histoplasmosis in immunosuppressed patients are similar in that, with one exception, granulomatous inflammation was not demonstrated. Thirteen eyes in which histoplasma organisms have been found in the eye are reviewed.

Adult↗

PubMed1989

The Glaucoma Laser Trial. I. Acute effects of argon laser trabeculoplasty on intraocular pressure. Glaucoma Laser Trial Research Group.

The Glaucoma Laser Trial Research Group has examined the acute effects of argon laser trabeculoplasty on immediate change in intraocular pressure and the formation of peripheral anterior synechiae among the 271 eyes assigned to argon laser trabeculoplasty as initial treatment for primary open angle glaucoma. Argon laser trabeculoplasty was administered in two sessions. Intraocular pressure rises of greater than 5 mm Hg occurred in 34% of eyes after one or both of the treatment sessions; intraocular pressure rises of greater than 10 mm Hg occurred in 12%. Eyes that had an intraocular pressure rise after the first session were more likely to have a rise after the second session than eyes with no rise after the first session. Among the many patient, eye, and treatment characteristics examined, only pigmentation of the trabecular meshwork was strongly associated with intraocular pressure rises. Forty-six percent of eyes developed greater than or equal to 1 degree of peripheral anterior synechiae. Brown iris color and posterior placement of laser burns were associated with higher rates of peripheral anterior synechiae formation.

Adult↗

PubMed2006

Choroidal innervation and optic neuropathy in macacque monkeys with laser- or anterior chamber perfusion-induced short-term elevation of intraocular pressure.

Long-term intraocular pressure (IOP) elevation leads to a significant reduction of the intrinsic choroidal innervation and axon loss in the optic nerve. In this study we investigated early changes in these tissues in order to clarify the putative sequence of events between choroidal ganglion cell loss and optic nerve axon loss in 19 monkeys with experimentally induced glaucoma. After 1 month of increased IOP, severe optic neuropathy but no reduction of choroidal ganglion cells (CGC) was detectable. Beginning at 2 months after treatment signs of degeneration in CGC morphology were observed. Laser treatment of the trabecular meshwork without IOP elevation caused no changes in choroidal innervation. Our results show that there is no apparent association between reduction of CGC and optic neuropathy in the early stages of IOP elevation.

Animals↗

PubMed2003

A new technique for removing the inner wall of Schlemm's canal using cyanoacrylate.

PURPOSE: To introduce a new technique for removing the inner wall of Schlemm's canal using cyanoacrylate. METHODS: Two donor eyes were used in this study. A limbal-based scleral flap was dissected. The external wall of Schlemm's canal was opened and the inner wall of Schlemm's canal was exposed. Ethyl-2-cyanoacrylate was applied uniformly to the inner wall. After it had solidified, it was removed with fine forceps. The operated sites were then studied by light microscopy. RESULTS: After cyanoacrylate removal, the aqueous humour was seen percolating through the thin remaining trabecular meshwork. Histopathological findings at the operated sites revealed that the lining of the Schlemm's endothelial cells was irregular. Endothelial cell nuclei were rarely seen along the canal wall. Microperforation to the anterior chamber was not seen. CONCLUSION: This new technique is potentially a safer method for removing the inner wall of Schlemm's canal than the conventional method.

Aqueous Humor↗

PubMed1990

[The effect of silicone oil on the ocular tissues].

It has been pointed out that the silicone oil tamponade can result in complications such as corneal damage, elevation of intraocular pressure and retinal toxicity against. The effect of silicone oil on the ocular tissues was investigated histopathologically by injecting silicone oil into the anterior chamber of the eyes of rabbits. In addition, in order to study its effect on the retina, silicone oil was injected into the vitreous cavity after vitrectomy. The eyes were extracted 3, 6, 9, 12 and 18 months after injection and various tissues were observed by light and electron microscopy. Silicone oil particles were first observed in the retro-corneal membrane 18 months after injection. In the trabecular meshwork silicone oil particles were seen for the first time 12 months after injection. Migrating cells engulfing silicone oil particles were attached to the internal limiting membrane of the retina three months after injection. Twelve and 18 months after injection, silicone oil particles passed through the internal limiting membrane and were engulfed by Mueller cells.

Animals↗

PubMed1998

[Intracanalicular trabeculostomy--a new approach to glaucoma surgery].

BACKGROUND: A new "ab externo" technique for glaucoma trabecular surgery creating multiple perforations of the trabeculum to improve outflow facility was tested. MATERIAL AND METHOD: In order to perform a draining canal to the anterior chamber, a quartz fiber (phi: 300 microns) with a side-firing tip, coupled to an Er:YAG laser (2.94 microns), was inserted into Schlemm's canal of an enucleated human eye. RESULTS: Eight pulses of 8 mJ each were sufficient to perforate the trabecular meshwork. Histologic analysis showed a rippled canal with 50 microns average diameter and a surrounding necrosis zone of 15-35 microns. CONCLUSIONS: The Er:YAG laser trabeculostomy, in conjunction with special fibers, shows promise as a new "ab externo" technique for minimally invasive therapy of open angle glaucoma.

Endoscopes↗

PubMed1999

Latrunculin-A increases outflow facility in the monkey.

PURPOSE: To determine the effect of Latrunculin (LAT)-A, a macrolide that binds to G-actin, which leads to the disassembly of actin filaments, on shape, junctions, and the cytoskeleton of cultured bovine aortic endothelial cells (BAECs) and on outflow facility in living monkeys. METHODS: Latrunculin-A dose-time-response relationships in BAECs were determined by immunofluorescence and phase contrast light microscopy, facility by two-level constant pressure anterior chamber perfusion. RESULTS: In BAECs, LAT-A caused dose- and incubation time- dependent destruction of actin bundles, cell separation, and cell loss. Cell-cell adhesions were more sensitive than focal contacts. Recovery was also dose- and time-dependent. In monkeys, exchange intracameral infusion and topical application of LAT-A induced dose- and time-dependent several-fold facility increases. The facility increase was completely reversed within several hours after drug removal. However, for at least 24 hours after a single topical LAT-A dose, perfusion with drug-free solution caused an accelerated increase in facility beyond that attributed to normal resistance washout. CONCLUSIONS: Pharmacological disorganization of the actin cytoskeleton in the trabecular meshwork by specific actin inhibitors like LAT-A may be a useful antiglaucoma strategy.

Actins↗

PubMed1981

Argon laser trabecular surgery in uncontrolled phakic open angle glaucoma.

Thirty-five phakic eyes from a predominantly black population with clinically uncontrolled open angle glaucoma underwent argon laser treatment to 360 degrees of the trabecular meshwork. The intraocular pressure in the untreated eye was used as a control whenever possible. The mean pressure change in the treated eye at four months showed a decrease of 10.0 mm Hg (P less than 0.001). This effect was maintained throughout the 18-month follow-up period. Thirty-four of the 35 eyes (97%) were clinically controlled with pressures averaging less than 20 mm Hg. The procedure appears to function by improving outflow facility as manifested by a statistically significant increase in outflow for six months post-treatment. The major complication was the formation of peripheral anterior synechiae. These synechiae were localized and did not affect the success of the procedure. Argon laser trabecular surgery appears to be effective in lowering intraocular pressure with many advantages over standard filtering surgery.

Adult↗

PubMed1995

Traumatic glaucoma.

In the management of an ocular injury, traumatic glaucoma is often overlooked. Prospectively reviewing 100 consecutive patients of traumatic glaucoma we found a very high correlation of postconcussional glaucoma with traumatic cataracts, angle recession of more than 180 degrees, significant injuries to the iris and a displacement of the lens. Two of these four clinical features were present in all cases. Penetrating injuries were followed by a secondary glaucoma if an adherent leucoma and/or evidence of lenticular damage or displacement were seen. These clinical features all point to a damage to the lens-iris diaphragm. The trabecular meshwork being directly related to these structures would also be involved in such an injury, leading to significant impairment of function, and the eye would therefore be more prone to developing glaucoma. Our study has highlighted certain clinical findings which could act as 'markers' for the early diagnosis of traumatic glaucoma.

Adolescent↗

PubMed1999

Hyaluronan synthase expression in bovine eyes.

PURPOSE: Hyaluronan (HA), a high-molecular-weight linear glycosaminoglycan, is a component of the extracellular matrix (ECM). It is expressed in eyes and plays important roles in many biologic processes, including cell migration, proliferation, and differentiation. Hyaluronan is produced by HA synthase (HAS), which has three isoforms: HAS1, HAS2, and HAS3. In this study, the HAS expression in the anterior segment of bovine eyes was investigated to determine the significance of HA in eyes. METHODS: To obtain bovine HAS probes, degenerate oligonucleotide primers, based on well-conserved amino acid sequences including the catalytic region of each HAS isoform, were used for reverse transcription-polymerase chain reaction to amplify mRNA from bovine corneal endothelial cells (BCECs). Hyaluronan synthase-1 expression in the anterior segment of bovine eyes at the protein level was investigated by immunohistochemistry. RESULTS: All three HAS isoforms were expressed in BCECs at the mRNA level. Amplified cDNA fragments of HAS1, HAS2, and HAS3 from BCECs can be aligned to human counterparts, showing similarities of 100%, 97.3%, and 100%, respectively, at the amino acid level. Hyaluronan synthase 1 was expressed at the protein level in corneal epithelium, keratocyte, corneal endothelium, conjunctival epithelium, ciliary epithelium, capillary endothelium, and trabecular meshwork. CONCLUSIONS: Hyaluronan synthase isoforms were expressed in the ocular anterior segment and are speculated to be involved in HA production in situ.

Amino Acid Sequence↗

PubMedDate not supplied

Ultrastructural studies of primary congenital glaucoma in rabbits.

BACKGROUND: The cause of congenital glaucoma is unknown. METHODS: To determine whether the site of impaired aqueous outflow is the entrance to the trabecular meshwork (TM), within the TM, the aqueous drainage plexus, or a combination thereof, the process of TM development was examined by scanning and transmission electron microscopy on postnatal day 3 and weeks 1, 2, 3, 4, and 6 in New Zealand rabbits homozygous for the buphthalmic (bu/bu) gene compared with age-matched controls. RESULTS: Openings to the entrance of the TM in congenital glaucoma were observed, and there was no evidence of an endothelial membrane occluding aqueous flow to the TM. The morphology of the congenital glaucoma TM was abnormal in all bu/bu rabbits by 2 weeks and was characterized by a smaller entrance to the TM at the iris base, smaller intertrabecular openings within and between the trabecular lamellae, and at 6 weeks, iris pillars with extensive lateral extensions in the angle recess. Most intertrabecular spaces were open, however, the inner intertrabecular spaces adjacent to the aqueous plexus were compressed. CONCLUSION: These results suggest the development of congenital glaucoma, which involves a mutation in an autosomal recessive gene and leads to loss of function of a gene(s) required for the differentiation of the TM.

Aging↗

PubMed2001

Interphase fluorescence in situ hybridisation of the X and Y chromosomes in the human eye.

AIM: To determine the sex of individual cells in paraffin sections of the human eye by fluorescence in situ hybridisation (FISH) of the X and Y chromosomes. METHODS: The authors developed a protocol for FISH of the X and Y chromosomes in paraffin sections of human eyes. RESULTS: In all the specimens that had been fixed in 10% formalin and with a fixation time of up to 3 days sex determination of individual cells was achieved. The percentage of cells with clearly identifiable signals was up to 98% for corneal epithelium, keratocytes, corneal endothelium, trabecular meshwork, lens epithelium, retina, and optic nerve. CONCLUSIONS: FISH allows the determination of the sex of single cells in paraffin sections of human eyes without destruction of the tissue structure. Its main application is the histological analysis of sex mismatched corneal, RPE, or neuroretinal transplants to distinguish host and donor cells.

Cornea↗

PubMed1989

Trabecular precipitates and elevated intraocular pressure following argon laser trabeculoplasty.

Two patients with pseudoexfoliation glaucoma underwent argon laser trabeculoplasty for control of intraocular pressure. Within 1 month both patients developed elevated intraocular pressure associated with many large inflammatory precipitates on the trabecular meshwork detected only by gonioscopy. Treatment with topical steroids for 7 to 10 days resolved these precipitates and lowered the intraocular pressure. We believe our patients had severe trabeculitis occurring as a late reaction to argon laser trabeculoplasty. An increase in intraocular pressure following trabeculoplasty warrants careful gonioscopic examination; in fact we recommend routine gonioscopy for all patients after laser treatment.

Aged↗