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Results for “Tenon Capsule”

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At least 325 records · Page 18Linked to original sources

PubMed1995

Effects of topically applied mitomycin-C on intraocular pressure, facility of outflow, and fibrosis after glaucoma filtration surgery in clinically normal dogs.

The effects of mitomycin-C on intraocular pressure (IOP), facility of outflow (C), and Tenon's capsule fibrosis were studied over 60 days in 10 clinically normal dogs. A-1-piece, silicone glaucoma implant was surgically implanted into both eyes; the filtration site of one eye was treated with a single, 5-minute intraoperative application of mitomycin (0.5 mg/ml), and the fellow eye was treated in a similar manner with balanced salt solution. There were no significant differences in preoperative IOP or C-values between treatment groups. Mean IOP in eyes of both groups initially decreased from the preoperative value, but returned to the baseline value by day 21. Mean facility of aqueous outflow (C-value) increased in all eyes during the first 14 days (mitomycin-C-value = 2.26 +/- 0.72; control C-value = 2.38 +/- 0.81), then reached a plateau that was significantly higher than the baseline value in mitomycin (P = 0.039) and control (P = 0.041) eyes. Histologic evaluation revealed all implants surrounded by a connective tissue capsule composed of regular dense collagen and fibroblasts that was significantly (P = 0.003) thinner in the mitomycin-treated (scleral side = 167 +/- 62 microns; conjunctival side = 122 +/- 41 microns) than the control (scleral side = 261 +/- 92 microns; conjunctival side = 180 +/- 48 microns) group. There were, however, no significant differences in IOP or C-values between groups at any postoperative time interval. Results of this study indicate that intraoperative treatment with mitomycin suppresses, but does not prevent fibrosis around silicone filtering implants.

Animals↗

PubMed1994

[Human dirofilariasis in southern Italy. I. The Puglia Region].

Nine new cases of human Dirofilariasis by Dirofilaria repens, in subjects living in Apulia, aged 30 to 60 years, are reported. Six were subcutaneous and three subconjunctival. Many of them occurred a number of years ago and were identified thanks to a specific joint investigation carried out by a parasitologist, some histopathologists and ophthalmologists. Of special relevance is one subcutaneous case with contemporary presence of 2 nodules in different regions of the body (mamma and forearm) and another subconjuctival case with strong inflammatory reaction (episcleritis, chemosis, orbital cellulitis) associated with the passage of the nematode under the Tenon's capsule.

Adult↗

PubMed1995

[Prevention of postenucleation syndrome: the hydroxylapatite silicone implant. Preliminary experimental studies and initial clinical experiences].

An orbital implant after enucleation compensates for volume deficiency and increases prosthesis motility. In the literature, however, an extrusion rate of orbital implant between 10 and 25% is reported. Since the introduction of hydroxylapatic ceramics (HAC), these numbers have been reduced considerably. The HAC, which is derived from corals, has a rough surface and requires a scleral covering for implantation. The HAC, which is made in the laboratory, can be produced with smoother surfaces, so that a homoplastic covering is no longer mandatory. A composite implant was developed to improve prosthesis motility further. This consists of artificial HAC at its anterior surface to guarantee safe tissue integration; the posterior part of the implant is manufactured from silicon rubber to create a jointlike structure in Tenon's capsule. Integration of the porous HAC in the orbital soft tissues has been tested and confirmed by animal experiments. After 30 full HAC implants and 25 composite implants, only one extrusion occurred. In all other cases, compatibility proved to be excellent; transmission of the motility to the prosthesis was moderate to good. Examinations comparing prosthesis motility and computer tomographically evaluated implant motility enabled the analysis of deficits in motility transmission of the implant for the artificial eye.

Animals↗

PubMed1993

Minoxidil inhibits ocular cell proliferation and lysyl hydroxylase activity.

PURPOSE: To examine the antiproliferative and lysyl hydroxylase-suppressing effects of minoxidil on cultured proliferating and density-arrested human retinal pigment epithelial cells (hRPE) and Tenon's capsule fibroblasts (hTCF). METHODS: Proliferating and density-arrested hRPE and hTCF, exposed to minoxidil (0.1-5 mM) for 15 min to 7 days, were examined by proliferation assays, [3H]thymidine incorporation, trypan-blue exclusion, and phase-contrast microscopy. The lysyl hydroxylase-suppressing effects were examined in confluent hRPE exposed to minoxidil (0.01-1 mM) using L-[4,5-3H]-lysine-labeled procollagen substrate and measuring the amount of tritium released as 3H2O after vacuum distillation. RESULTS: Minoxidil (0.1-5 mM) inhibited the proliferation of subconfluent cultures of hRPE and hTCF in a dose-dependent manner with a half-maximal effect at 1.5 and 2.5 mM, respectively. The antiproliferative effect, detectable within 24 hr, occurred with a limited exposure period and persisted even after removal of minoxidil from the culture medium. In contrast, 1-5 mM minoxidil had minimal effect on density-arrested hRPE and hTCF. However, at doses above 3 mM, although minoxidil had no effect on the number of density-arrested hRPE, morphologic and viability experiments indicated signs of cytotoxicity. Minoxidil (0.1-1 mM) caused a maximum of 71% reduction in the activity of lysyl hydroxylase, an enzyme needed for stable cross-links in collagen. CONCLUSIONS: Minoxidil may be a useful drug for the treatment of conditions such as proliferative vitreoretinopathy and bleb scarring after trabeculectomy, disorders with unwanted cell proliferation and collagen production.

Cell Count↗

PubMed1995

[A case of encapsulated filtering bleb after trabeculectomy].

A case of encapsulated filtering bleb after trabeculectomy is reported. A 57-year-old man with primary open angle glaucoma underwent a trabeculectomy one year ago. Six months after the operation the filtering bleb began to shrink and intraocular pressure (IOP) began to rise. It was suspected that the trabeculectomy site was obstructed by scarring, and so sclerostomy ab interno was performed in the site with a Nd: YAG laser. The IOP was higher elevated, however, and the bleb remained unchanged with severe conjunctival injection and aqueous inflammation. The next day trabeculectomy was performed in a new site and two weeks later a dome-shaped, prominent bleb was observed with an increase in the IOP. This was diagnosed as an encapsulated filtering bleb (Tenon's capsule cyst). Cystectomy of the bleb failed and it recurred, therefore, another trabeculectomy was added and the IOP was kept at a reasonable value. We believe that it is important to pay attention to an encapsulated filtering bleb as a complication of filtering surgery after laser therapy to the anterior chamber angle.

Conjunctiva↗

PubMed1995

Total integration of an ocular implant/prosthesis: preliminary in vivo study of a new design.

An ocular implant designed to simplify surgical implantation, minimize infection and extrusion, and improve motility when used as a prosthetic replacement for eyes removed because of damage or disease was tested in rabbit eyes. The implant consisted of a silicone sphere with patches of porous silicone elastomer at the natural insertion sites of the extraocular muscles. Nine implants also had patch material around the base of an integral post designed to distribute the weight of and transfer motility to an overlying prosthetic conformer. Six implants without posts had a circular porous patch on the central anterior surface to facilitate closure of the conjunctiva and Tenon's capsule. Biocompatibility and feasibility were tested in rabbit eyes for < or = 1 year. The patches promoted conjunctival ingrowth, leading to positional stability, and facilitated adherence of the extraocular muscles. Patch material around the post or on the anterior conjunctival surface enhanced conjunctival closure and healing. All 15 implants were retained with no signs of migration, conjunctival dehiscence, or extrusion. Motility on forced duction testing was significant in all directions. The materials appeared to be biocompatible, and the design with the post provided good motility, with the potential for improved coordinated eye movement as a result of the specifically localized attachment of the extraocular muscles.

Animals↗

PubMed1997

Internal sclerostomy with a mechanical trephine versus the neodymium:YAG laser in dogs.

BACKGROUND AND OBJECTIVES: To experimentally compare and contrast the internal sclerostomy produced using a mechanical trephine with that made by an Nd:YAG laser, and to evaluate the healing patterns, efficacy, and technical advantages of each method. MATERIALS AND METHODS: Four healthy dogs with normal eyes were used in this study. The left eye of each dog had an internal sclerostomy performed with an automated mechanical trephine. The right eye of each dog had an internal sclerostomy performed with an Nd:YAG laser. Postoperatively, the intraocular pressure of each eye was measured at regular intervals. The dogs were euthanized successively at 1, 2, 3, and 4 weeks postoperatively, and the morphology of the surgical sites was studied. RESULTS: The Nd:YAG laser was easier to manipulate and technically less demanding than the mechanical trephine. However, the Nd:YAG laser induced more prominent corneal edema and conjunctival hyperemia compared with the automated trephine. Morphology of the tissue response showed tissue necrosis and greater inflammation with the Nd:YAG laser than with the automated trephine. CONCLUSIONS: These two techniques demonstrate differences in technical demands and tissue response. Both are characterized by minimal reactive fibrosis of the episcleral and Tenon's capsule fibroblast.

Animals↗

PubMed1977

Details of the orbital connective tissue system in the adult.

The study of serial thick (60 mu) histological sections reveals a highly complicated but orderly constructed connective tissue system within the orbit. Between this system adipose tissue compartments are present built up in a comparable orderly fashion. In this intraorbital continuum, to which Tenon's capsule, the so-called check ligaments, the fascial sheaths of the muscles and the periorbital membrane belong, other different areas of characteristic connective tissue septa originating from the fascial sheaths of the eye muscles are recognizable. These different areas are linked to the presence of the different eye muscles and can be regarded as belonging to these eye muscles. That is why, in our opinion, this total of orbital connective tissue, together with the adipose tissue compartments lying in between, must be regarded as an additional mechanism playing an important role when eye movements are performed. The highly regular pattern and intra- and interindividual uniformity within this system will be clarified in the following paper, using models which specially highlight spatial architecture.

Adipose Tissue↗

PubMed1995

[Clinical study on allogenic conjunctival transplantation].

PURPOSE: To investigate the indications and outcome of human allogenic conjunctival transplantation. METHODS: The necrotic tissues and scars were removed from the fornix by using the residual conjunctiva. Then the allograft without Tenon's capsule was transplanted to cover the wound. RESULTS: At 6 postoperative months, the surface was completely healed in 76%x. For patients with mechanical trauma or thermal burn, the area of transplanted conjunctiva was less than one third, or using donor conjunctiva from parents or siblings are of better prognossis. CONCLUSIONS: 1) Allogenic conjunctival transplantation is a feasible treatment for servere symblephron and lid defects. 2) The result is poor when residual conjuctiva is less than 1/2. 3) The outcome is best in mechanical trauma and worst in alkaline burns, with thermal burns somewhere in between. 4) The simple bulbal conjunctival transplantation has better results.

Adolescent↗

PubMed1997

Cell attachment to, and contraction of, the retina in vitro.

PURPOSE: To examine the behavior of fibroblasts and retinal pigment epithelial cells after attachment to the retinal surface in vitro to elucidate the pathobiology of the early stages of epiretinal membrane formation. METHODS: Human retinal pigment epithelial (HRPE) cells and bovine Tenon's capsule fibroblasts (BTFs) were seeded onto the surface of bovine retinal explants maintained in organ culture. The changes induced in the underlying retina, including contraction, were assessed during a period of up to 10 days. Immunohistochemistry was used to assess proliferation of the seeded cells and to determine deposition of extracellular matrix. RESULTS: Explants of bovine neuroretina were maintained in organ culture, with good morphologic preservation of the inner limiting lamina and inner retinal layers, for 7 to 10 days. The HRPE cells and the BTFs attached to the retinal surface and exerted tractional forces, producing partial- and full-thickness retinal folding. Contraction commenced within 24 hours of attachment of the cells and continued for several days, with most of the contraction occurring within the next 48 to 72 hours. The HRPE cells and BTFs were found to be equally contractile. Deposition of cellular fibronectin (but not collagen type I) was demonstrated. CONCLUSIONS: The contractile cellular membranes generated in this organ culture system exhibit many of the morphologic and functional features of epiretinal membranes found in the early stages of proliferative vitreoretinopathy.

Adult↗

PubMed1997

Fornix-based trabeculectomy with mitomycin-C.

BACKGROUND AND OBJECTIVE: Mitomycin-C (MMC) has been shown to improve the surgical success of trabeculectomy; however, the advantages of MMC have been evaluated almost entirely as an adjunct to limbal-based trabeculectomy. This study evaluated the efficacy and safety of fornix-based trabeculectomy with MMC for glaucomatous patients. PATIENTS AND METHODS: Between January 1993 and April 1995, 71 patients underwent fornix-based trabeculectomy with topical application of 0.4 mg/ml of MMC for 3 minutes. The conjunctiva-Tenon's capsule flap was spread over the limbus and sutured in order to create a visible crease with a water-tight closure. The mean follow-up time was 14.5 months. RESULTS: The mean intraocular pressure (IOP) before surgery was 32.4 +/- 9.7 mm Hg. The average postoperative IOP was 14.04 +/- 9.57 mm Hg. An IOP of 20 mm Hg or less was observed in 57 eyes (80%). Postoperatively, 37 eyes (52%) required no additional medical therapy. One month after surgery, only 2 patients had wound leakage with hypotony and choroidal detachment. Two eyes (3%) had suprachoroidal hemorrhage with loss of vision. A conjunctival "buttonhole" occurred in 2 eyes (3%), but only 1 persisted more than a month. CONCLUSIONS: Fornix-based trabeculectomy using intraoperative application of 0.4 mg/ml of MMC for 3 minutes was found to be as safe and effective as limbal-based trabeculectomy with MMC.

Adult↗

PubMed1997

Ascorbate stimulates type I and type III collagen in human Tenon's fibroblasts.

PURPOSE: To better understand wound healing after glaucoma filtration surgery by measuring the production of type I and type III collagen in cultured Tenon's fibroblasts and determine the effect of ascorbic acid on collagen subtype production. METHODS: An ELISA-type dot blot assay was used to directly measure the production of types I and III collagen by subconfluent cultures of fibroblasts from human Tenon's capsule. Because ascorbic acid is both high in aqueous humor and necessary for the production of collagen, we measured the dose response of type I and type III collagen production to ascorbic acid. RESULTS: Ascorbic acid stimulated an increase in collagen production that reached a maximum level at 100 micrograms/ml. This is approximately half of the ascorbic acid concentration found in human aqueous humor. Unlike previous reports, we found no toxic effects from ascorbic acid at concentrations as high as 250 micrograms/ml over a 24-hour period. The lack of toxicity may result from the use of serum-free media in the assay. CONCLUSIONS: This culture system will be useful for exploring factors that may alter collagen production and could potentially affect wound healing.

Ascorbic Acid↗

PubMed1997

[Subconjunctival adipose hernias of the orbit].

Clinical report of three cases of subconjunctival fat prolapse. Differential diagnoses are discussed. Subconjunctival orbital fat prolapse is a benign entity with a fat herniation through defective Tenon's capsule.

Adipose Tissue↗

PubMed1998

Retrospective analysis of a novel method of transscleral suture fixation for posterior-chamber intraocular lens implantation in the absence of capsular support.

PURPOSE: To determine the safety and efficacy of an alternative method for transscleral fixation of a secondary posterior-chamber intraocular lens (pcIOL) during penetrating keratoplasty. METHODS: Eighty-nine eyes that underwent secondary pcIOL implantation by using a modified transscleral suture-fixation technique during penetrating keratoplasty were retrospectively evaluated. The surgical technique used suture fixation to the surface of the sclera 5 mm posterior to the limbus, with the knot buried beneath Tenon's capsule and conjunctiva. Patient records were reviewed for postoperative complications, including suture erosion, pcIOL subluxation, vitreous hemorrhage, and retinal detachment. Mean follow-up was 24.4 months, with a range of 4-68 months. RESULTS: All eyes had successful fixation of their pcIOL immediately after surgery. Three (3.3%) eyes had graft failure. Six (6.7%) of 89 eyes showed evidence of suture erosion or partial exposure. Postoperative suture breakage occurred in two (2.2%) eyes. Posterior-segment complications included retinal detachment in one (1.1%) eye, vitreous hemorrhage in one (1.1%) eye, and limited choroidal hemorrhage in two (2.2%) eyes. Median visual acuity at 1-year follow-up was 20/70 (range, 20/25 to light perception). CONCLUSION: This transscleral fixation technique provides a straightforward alternative to previously described techniques. Suture erosion, IOL dislocation, and posterior-segment complications occurred at relatively low rates compared with other pcIOL implantation techniques.

Adult↗

PubMed2003

[The failure causes of non-penetrating trabecular surgery and reoperation].

OBJECTIVE: To study the failure causes of non-penetrating trabecular surgery (NPTS) with SKGeL (a hyaluronic acid biological gel) implant and the surgical method of reoperation. METHODS: Repeated operation with mitomycin (MMC) through the initial surgical site was performed on 13 failure cases (13 eyes) that had undergone NPTS with SKGeL implant. The blockage of filtration tract was removed and the anterior chamber was intact during the surgery. All of these cases were open-angle glaucoma. Before the repeated surgery ultrasound biomicroscopic (UBM) examination was performed on the primary filtering bleb, and the intraocular pressure (IOP) examination was followed after the repeated operation. RESULTS: The mean follow-up period was (14.0 +/- 5.8) months (6 to 24 months). The examination of UBM showed that the filtering bleb disappeared and there was a liquid chamber under the superficial scleral flap in every failure case. The filtration failure due to the scarring at conjunctiva-Tenon's capsule-superficial scleral flap interface in 9 cases, proliferative membrane formation on the trabecular surface in 3 cases, micro-penetration of the trabecula in 1 case. At the end of follow-up, the IOP of 10 cases was lower than 21 mmHg without medication, the mean IOP level was (14.1 +/- 3.7) mm Hg, the IOP of 1 cases was 15 mmHg with Betagen, another 2 cases failed again 6 months after the repeated surgery and underwent the trabeculectomy at last. The complications included hyphema in one case and micro-penetration of the tabecula in one case. CONCLUSIONS: The scarring at conjunctiva-Tenon's capsule-superficial scleral flap interface was the most important cause of NPTS with SKGeL implant failure. A repeated surgery with MMC through the initial surgical site may be a choice for the failure cases.

Adult↗

PubMed1991

Fibroblast and endothelial outgrowth from human Tenon's explants: inhibition of fibroblast growth by 5HT receptor antagonism.

Tenon's layer capsule is a major source of fibroplasia associated with post-traumatic wound healing in the external eye and failure of filtration surgery for glaucoma (trabeculectomy). We have investigated the cell types involved in outgrowth from human Tenon's layer explants in culture. Outgrowth from explants maintained in fetal bovine serum (5%) and fibroblast conditioned medium (25%) consisted of endothelial cells exhibiting factor VIII antibody staining and were located to sectioned capillary ends. In media supplemented with human serum (10%), fibroblast outgrowth was observed from the entire perimeter of explants. The mitogenic stimulus of human serum on fibroblasts, monitored by 3H-thymidine uptake, was dose-dependent and accompanied by a 200% increase in inositol phosphate production. 5HT induced a significant increase in fibroblast proliferation and 5HT receptor antagonism with methysergide (20 microM) reduced serum-induced mitogenesis by 30%. These findings support the role of fibroblasts in failure of filtration surgery for glaucoma and suggest a role for 5HT in serum-derived Tenon's fibroplasia.

Blood↗

PubMed2004

Managing intraoperative complications in cataract surgery.

PURPOSE OF REVIEW: This article surveys the literature from 2002 and 2003 and addresses a variety of complications that may arise during cataract surgery. Modern surgical techniques and technology contribute to the decreased incidence of complications. Surgeon experience, early recognition of potential complications, and optimal handling of events lead to better outcomes. RECENT FINDINGS: Recognizing eyes preoperatively that are particularly at risk for having dysgenesis of the capsular bag, cortical-capsular adhesions, low endothelial cell reserve, dropped nucleus, and bag-lens dislocation will allow for contingency planning and appropriate tailoring of techniques. Capsular tension rings are indispensable for achieving in-the-bag implantation in the presence of weak zonules and zonulolysis. Viscolevitation to rescue sinking implants, avoidance of foldable lens complications, and proper lens placement with an open capsule are discussed. High-frequency ultrasound biomicroscopy is a useful diagnostic tool. Noninjection sub-Tenon anesthesia is not benign. Complications have been documented that include traumatic optic neuropathy. Immediate diagnosis and a trial of corticosteroids could be vision saving. Mastering topical anesthesia is a worthy goal. In some cases, faulty instruments result in complications. Routine inspection of reusable instruments, or the use of disposable instruments is warranted. Though there is no FDA-recognized use, at the time of this writing, for trypan blue dye, it has become the world standard for intraocular staining because of its safety and efficacy. Clear corneal self-sealing incisions are increasingly mainstream and, when properly constructed, are extremely secure. The most significant trend for successful management of intraoperative complications this year is the increasing use of pars plana anterior vitrectomy. The ability to identify prolapsed vitreous by intracameral Kenalog staining is an invaluable tool. Surgeons depend on a team of nurses and technicians for optimal outcomes. SUMMARY: With new technology and techniques highlighted by capsular tension rings, Kenalog vitreous identification, and fourth-generation fluoroquinolones, even complicated cataract surgery can result in optimal outcomes.

Cataract Extraction↗

PubMed2002

The Auckland cataract study: co-morbidity, surgical techniques, and clinical outcomes in a public hospital service.

AIM: To prospectively assess cataract surgery in a major New Zealand public hospital by defining presenting clinical parameters and surgical and clinical outcomes in a cohort of subjects just below threshold for treatment, based upon a points based prioritisation system. METHODS: The prospective observational study comprised 488 eyes of 480 subjects undergoing consecutive cataract operations at Auckland Hospital. All subjects underwent extensive ophthalmic examination before and after surgery. Details of the surgical procedure, including any intraoperative difficulties or complications, were documented. Postoperative review was performed at 1 day and 4 weeks after surgery. Demographic data, clinical outcomes, and adverse events were correlated by an independent assessor. RESULTS: The mean age at surgery was 74.9 (SD 9.6) years with a female predominance (62%). Significant systemic disease affected 80% of subjects, with 20% of the overall cohort exhibiting diabetes mellitus. 26% of eyes exhibited coexisting ocular disease and in 7.6% this affected best spectacle corrected visual acuity (BSCVA). A mean spherical equivalent of -0.49 (1.03) D and mean BSCVA of 0.9 (0.6) log MAR units (Snellen equivalent approximately 6/48) was noted preoperatively. Local anaesthesia was employed in 99.8% of subjects (94.9% sub-Tenon's). The majority of procedures (97.3%) were small incision phacoemulsification with foldable lens implant. Complications included: 4.9% posterior capsule tears, 3.8% cystoid macular oedema, and one case (0.2%) of endophthalmitis. Mean BSCVA after surgery was 0.1 (0.2) log MAR units (6/7.5 Snellen equivalent), with a mean spherical equivalent of -0.46 (0.89) D, and was 6/12 or better in 88% of all eyes. A drop in BSCVA, thought to be directly attributable to the surgical intervention, was recorded in a small percentage of eyes (1.5%) after surgery. CONCLUSION: This study provides a representative assessment of the management of cataract in the New Zealand public hospital system. A predominantly elderly, female population, frequently exhibiting significant systemic illness and coexisting ocular disease, relatively advanced cataracts, and poor BSCVA, presented for cataract surgery. The majority of subjects underwent small incision, phacoemulsification, day case surgery. While almost 90% achieved at least 6/12 BSCVA post-surgery, approximately 5% sustained an adverse intraoperative event and 1.5% of eyes exhibited a reduction in BSCVA postoperatively.

Adult↗