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Biomedical subjects

B Kirchhof

Publications and source records attributed to B Kirchhof.

At least 19 recordsLinked to original sources
PubMed1999

Macular translocation for surgical management of subfoveal choroidal neovascularizations in patients with AMD: first results.

BACKGROUND: At present no satisfying treatment for subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) is available. Visual results after successful surgical removal of subfoveal CNV are disappointing. This has been explained by a primary dysfunction of the retinal pigment epithelium (RPE) in the macular region and the surgical trauma to the RPE in patients with AMD. Therefore, Machemer and Steinhorst developed a technique for macular translocation after surgical removal of subfoveal CNV. We report our first experiences with this technique in patients with subfoveal CNV secondary to AMD. METHODS: Seven patients aged between 71 and 83 years with subfoveal CNV were included in the study. Visual acuity of the fellow eyes was below 20/400. All patients underwent pars plana vitrectomy. Retinal detachment was produced by subretinal infusion of balanced salt solution and a 360 degrees retinotomy at the base of the vitreous was performed. After removal of the CNV, retinal rotation and reattachment, the retina bordering the retinotomy was coagulated with endolaser photocoagulation. Silicone oil was used as temporary tamponade. RESULTS: In all patients the subfoveal CNV was removed and the macula was translocated by a 15 degrees-45 degrees rotation onto functional RPE. The mean duration of follow-up was 11 +/- 3 months. Initial visual acuity ranged from 20/80 to hand movements. Final visual acuity was 20/100 to 20/400. Initially all patients complained of tilted vision. During follow-up the rotation of the image regressed and was well tolerated by all patients. Complications included the development of retinal detachment in three patients after silicone oil removal, development of a macula pucker, and a significant increase of lens opacity in the phakic eyes. CONCLUSION: In our series rapid improvement of visual function was observed in one patient only, even if the macula appeared ophthalmoscopically and angiographically normal. Vitreoretinal complications occurred frequently during follow-up.

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PubMed1999

A new way of removing silicone oil from the surface of silicone intraocular lenses.

PURPOSE: This study was performed to ascertain the efficacy of Perfluorhexyl-octan, C14F13H17 (F6H8), in dissolving silicone oil from the surface of silicone intraocular lenses. So far F6H8 is the only solvent of silicone oil that is tolerated by intraocular tissues. MATERIALS AND METHODS: Intraocular silicone lenses (Domilens) were examined after application of small droplets of silicone oil of two different viscosities (AdatoSIL-OL 1000 and 5000) followed by rinsing with F6H8. To allow distinction between silicone oil and F6H8 the silicone oil was stained. Microscopic examination was carried out under video control. RESULTS: One hundred microliters of AdatoSIL-OL 1000 could be easily removed with about 800 microl of F6H8; 50 microl of AdatoSIL-OL 5000 also disappeared after 800 microl of F6H8. A larger drop of the latter oil could not be removed even after application of 2 ml of F6H8. CONCLUSION: Silicone oil 1000 can be easily dissolved by F6H8, whereas silicone oil 5000 is more difficult to remove because of its higher viscosity.

Equipment Contamination↗
PubMed1999

[Radiation therapy of occult choroidal neovascularisation (CNV) in age-related macular degeneration (AMD)].

BACKGROUND: Occult choroidal neovascularisation secondary to age-related macular degeneration cause severe visual loss due to exsudation, hemorrhage and fibrovascular scarring. So far, no efficient treatment of this condition could be established. Recently, some publications described an improved prognosis after low-dose radiation therapy of the neovascular membranes. PATIENTS AND METHODS: Patients with occult choroidal neovascularisation as defined by the Macular Photocoagulation Study were inclosed in our study. Irradiation with Photons (10 to 12 MeV) in fractions of 5 x 2 Gy were administered. At three-month follow-up intervals visual acuity a complete ophthalmological examination including visual acuity, fluorescein- and ICG-angiography as well as fundus photography was performed. RESULTS: In our study 64 patients (74 +/- 7 years) with occult CNV secondary to AMD were included. Follow-up was between 3 and 39 months (14.5 +/- 10). Compared to studies who investigated the natural history of this disease, the visual acuity measured in our study did not differ significantly from the natural course. CONCLUSIONS: Our results do not support the general use of radiation therapy in patients with occult choroidal neovascularisation secondary to AMD. However, the controlled multicenter studies might provide a better basis for a general recommendations.

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PubMed1999

The "Aachen" keratoprosthesis: a new approach towards successful keratoprosthesis-surgery.

BACKGROUND: None of the keratoprostheses available today is absolutely successful in the long term, neither the problems of extrusion, retroprosthetic membrane formation and intraocular pressure rise are yet solved. A new type of keratoprosthesis is required which can show improved ingrowth characteristics and allow intraocular pressure measurements. In order to possibly meet the above mentioned requirements we developed a flexible silicone keratoprosthesis with scleral fixation and chemical surface modification. METHODS: The one-piece keratoprosthesis is made of silicone rubber. Its optical zone has a diameter of 11 mm and is 0.3 mm thick. The surface-modified haptic consists of a scleral rim and eight branches for scleral fixation. A ridge at the back of the keratoprosthesis fitting into the trephination hole shall avoid leakage and retroprosthetic membrane formation. Optical and mechanical qualities are characterised by tensile tests, spectrophotometry and topography. RESULTS: A method for keratoprosthesis-production was established. The optical quality of the device was improved by submicron lathing of the mould. Spectrophotometry showed high visible and ultraviolet light transmission of the silicone. Mechanical tests with silicone samples revealed high tensile strength and elongation at break. The mechanical properties were not impaired by surface modification. CONCLUSIONS: The production of a flexible silicone keratoprosthesis with high optical and mechanical properties was established. Its use both for the treatment of permanently opacified corneas and as temporary keratoprosthesis seems to be possible.

Biomechanical Phenomena↗
PubMed1998

Granular corneal dystrophy: treatment with soft contact lenses.

Perforating keratoplasty was performed in both eyes of two siblings (sister and brother) with typical granular corneal dystrophy. Three of the operated eyes showed a recurrence of the underlying disease. In one eye, a recurrence could not be detected 14 years after the operation. This eye had been fitted with a contact lens 16 months after keratoplasty because of aphakia. Thus a contact lens may have a therapeutic effect in this primary epithelial disease.

Adult↗
PubMed1998

Temporary vitreous gas tamponade by perfluoromethylcyclopentane.

Using perfluoromethylcyclopentane (FMCP; US patent no. 5,441,989, granted 1995) we have developed a new vitreous gas tamponade in a rabbit model that allows complete filling of the vitreous cavity without vitrectomy and without a significant increase in intraocular pressure. In humans this procedure would allow the blockage of inferior and posterior retinal holes without special positioning of the patient. Perfluoromethylcyclopentane (FMCP), a liquid perfluorocarbon with a boiling point slightly above body temperature, is injected in minute volumes into the vitreous cavity, where it vaporizes, thereby filling a gas volume approximately 500 times its liquid volume. FMCP was injected into the midvitreous in six rabbits (six eyes). After 2-3 days a complete gas tamponade was achieved in three eyes. Two eyes showed 75-90% filling, and one eye was filled only 50% with gas. Intraocular pressure was highest in the completely filled eyes, ranging from 26.6 to 38.8 mmHg. In all eyes the maximum expansion of the gas bubble lasted 2 weeks. One eye developed a retinal detachment. All eyes showed transient subcapsular cataracts. The results of this study showed that intravitreal injection of FMCP, a new perfluorocarbon liquid, results in a complete gas tamponade of the vitreous cavity which lasts 2 weeks without severe intraocular pressure rise and without vitrectomy. This procedure will be especially useful for eyes that have retinal detachment from inferior or posterior retinal holes. Injection of a conventional gas such as SF6 or C3F8 usually does not block retinal holes in inferior or posterior locations without tedious positioning and risk of (transient) glaucoma. Since the mechanism of transition of FMCP from liquid to gas in the vitreous is poorly understood, we are currently studying FMCP vaporization in an in vitro eye model.

Animals↗
PubMed1998

Corneal injury after carbon dioxide laser skin resurfacing.

PURPOSE: To describe a corneal injury in both eyes of a patient who had undergone carbon dioxide laser skin resurfacing. METHOD: Case report. RESULTS: A 67-year-old woman had severe pain and decreased vision in both eyes after undergoing laser skin resurfacing treatment with a pulsed carbon dioxide laser. Clinical examination disclosed a corneal ulcer, a bullous keratopathy, and intrastromal bleeding. After perforating keratoplasty, the histologic examination of the cornea showed signs of thermal injury. CONCLUSIONS: The results of the histologic examination and the onset of symptoms within 24 hours after therapy suggest that the laser application caused the corneal damage. Safety guidelines for this procedure should be reviewed.

Aged↗
PubMed1998

Failure of sorivudine therapy in progressive outer retinal necrosis caused by varicella zoster virus.

BACKGROUND: We report on the case of a 23-year-old female who presented with ocular signs of progressive outer retinal necrosis (PORN) syndrome and who failed to respond to acyclovir, ganciclovir, foscarnet and oral sorivudine. METHODS: The patient was treated with the antiviral drugs acyclovir, ganciclovir, foscarnet and oral sorivudine. RESULTS: The patient failed to respond to a combination of antiviral drugs. Unfortunately, progression of the retintis occurred, which led to blindness. CONCLUSION: Despite new drugs, the prognosis of PORN is poor and recurrence is common.

AIDS-Related Opportunistic Infections↗
PubMed1998

Development of a surface modified silicone-keratoprosthesis with scleral fixation.

BACKGROUND: Many attempts have been made to create artificial corneas. The keratoprostheses currently available do not allow measurements of the intraocular pressure (IOP) and restrict the visual field. The main problem is extrusion due to an insufficient connection between implant and surrounding tissue. It is our aim to create a flexible keratoprosthesis with a wide field optic allowing measurements of the IOP. Surface modification will improve cell adhesion and therefore stability between implant and tissue. METHODS: The keratoprosthesis is made of silicone rubber. The optical zone is 11 mm in diameter with a thickness of 0.3 mm. The surface modified haptic consists of a scleral rim and 8 branches for scleral fixation. Optical and mechanical qualities were tested by tensile tests, spectrophotometry and topography. RESULTS: A method to produce one-piece silicone keratoprostheses was established. Submicron lathing of the mould led to an excellent optical quality. Spectrophotometry showed high degree of visible and ultraviolet light transmission of the silicone. Mechanical tests revealed high tensile strength and elongation at break which were not impaired by surface modification. CONCLUSION: The production of a flexible silicone keratoprosthesis with high optical and mechanical properties was accomplished, with possible use as both permanent and temporary keratoprosthesis.

Corneal Diseases↗
PubMed1997

Flecked chorioretinopathy associated with Birt-Hogg-Dubé syndrome.

BACKGROUND: Birt-Hogg-Dubé's syndrome is a rare skin disease characterized by multiple trichofibromas of the skin and polyps of the intestine. Ophthalmologic manifestations associated with the syndrome have not been reported in detail. CASE REPORTS AND METHODS: Two siblings suffering from Birt-Hogg-Dubé syndrome were examined clinically. Electrooculography and electroretinography were performed according to international standards. Color fundus photographs were taken as well as fluorescein angiograms. The two patients showed multiple perifollicular fibromas and trichodiscomas of the skin of the head. Funduscopy and fluorescein angiography revealed a flecked chorioretinopathy in one patient with progressive constriction of visual fields and severely reduced electroretinographic responses. Ophthalmoscopy in his sister showed peripheral pigmentary changes with only minor functional abnormalities. CONCLUSION: These findings suggest that Birt-Hogg-Dubé syndrome may be associated with a progressive flecked chorioretinopathy with constricted visual fields and that patients with the syndrome should undergo ophthalmological examination.

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PubMed1997

Management of fibrous histiocytoma of the corneoscleral limbus: report of a case and review of the literature.

BACKGROUND: Fibrous histiocytomas of the corneoscleral limbus are rare tumors. We present an additional case and review the treatment approaches in the literature. So far, only light and electron microscopic studies have been performed. We used immunohistochemical stains to further characterize the cellular composition. METHODS: The excised lesion was routinely fixed and processed for light microscopy and immunohistochemical studies. For comparison, three dermal fibrous histiocytomas were also examined and processed similarly. RESULTS: The corneolimbal tumor was mainly composed of fibroblasts and histiocytes with a large amount of interstitial collagen, arranged in a storiform pattern. Immunohistochemical stains were positive for histiocytes, fibroblasts, and a marker for mesenchymal cells. The staining pattern of the dermal lesions was similar. CONCLUSION: Fibrous histiocytomas of the corneolimbal region are morphologically benign, slowly growing and infiltrative tumors. Complete resection, especially of the deep margin, is suggested. The immunohistochemical staining pattern is similar to that of dermal fibrous histiocytomas, which behave in a benign manner.

Adult↗
PubMed1997

Branch retinal artery occlusion by diathermy of a persistent hyaloid artery.

PURPOSE: To report branch retinal artery occlusion caused by diathermy of a persistent hyaloid artery. METHODS: Case report. A 21-year-old woman with unilateral tractional retinal detachment caused by contraction of the persistent primary vitreous underwent vitrectomy with endocoagulation of the primary hyaloid artery. RESULTS: Postoperatively, the patient had opacification of the neurosensory retina in the area of the inferotemporal branch retinal artery accompanied by a corresponding visual field defect. CONCLUSIONS: Diathermy of a persistent hyaloid artery may be complicated by the occlusion of a branch retinal artery. In similar cases, atypical branches of retinal arteries must be considered. Dissection of the anomaly from the posterior lens capsule should be performed without coagulation or perhaps endoscopically if visualization is obscured by a Mittendorf dot.

Adult↗
PubMed1997

[Vitrectomy in treatment of eyes with complicated uveitis].

BACKGROUND: Vitrectomy serves as an important treatment modality in uveitis, removing inflamed vitreous body and eliminating secondary complications. The aim of our retrospective study was to evaluate the value of vitrectomy in the treatment of complications in uveitis. PATIENTS AND METHOD: We included 50 eyes of 50 patients suffering from chronic uveitis, which underwent vitrectomy surgery during the period of 1990 to 1993. The study only included patients who had vitrectomy for uveitis for the first time. Indications leading to surgery were density of optic media, retinal detachment, cyclitic or preretinal membranes. The mean follow-up was 455 (range 48-1420) days. RESULTS: Vitrectomy was performed at a mean delay of 452 days after initial presentation. The mean visual acuity at the time of surgery was 0.05. The best visual acuity postoperatively was measured at a mean time of 118 days after vitrectomy. Overall, at the last control, eyes with preoperative retinal detachment presented a much worse final functional result (visual acuity of 0.02) than eyes without detachment (visual acuity of 0.5). Ten eyes resulted in hypotonia after surgery (7 eyes with persisting hypotonia). Most frequent complications in the postoperative course were macular pucker (11 eyes), secondary glaucoma (10 eyes), macular edema (6 eyes) and retinal detachment (6 eyes). Fifty percent of all complications occurred within the first 3 months following surgery. CONCLUSION: Vitrectomy leads to a permanent increase in visual acuity through the treatment of complications, on the condition that a stable retinal situation was present preoperatively.

Adult↗
PubMed1997

The artificial iris diaphragm for vitreoretinal silicone oil surgery.

BACKGROUND: Silicone keratopathy frequently develops as a complication of silicone oil tamponade in the management of severe trauma in eyes with partial or complete aniridia. We therefore designed an "open" artificial iris diaphragm to prevent silicone oil-endothelial contact. In hypotony, where insufficient circulation of aqueous allows silicone in the anterior chamber despite an open diaphragm, a new solution became necessary. The "closed" artificial diaphragm was developed. METHODS: In this retrospective study, two consecutive series of artificial iris diaphragms were compared. Forty-four patients received either an open type (20 eyes) or a closed type (24 eyes) and were observed for 409 +/- 421 days (range, 32-1912). All eyes were aphakic, normotonous, and had a traumatic, compromised iris diaphragm or were aphakic and hypotonic as a result of injury, proliferative vitreoretinopathy, proliferative diabetic retinopathy, or uveitis, with an intact natural iris diaphragm. RESULTS: Silicone oil was retained behind the open diaphragm throughout the observation period in 40% of the eyes. Major long-term complications were hypotony and fibrous overgrowth. Silicone was retained behind the closed diaphragm in 50% of the eyes. CONCLUSION: Because proliferative vitreoretinopathy is active for months and multiple surgical interventions become necessary to avoid phthisis in eyes with highly pathologic changes, longstanding or permanent silicone tamponade is used. The artificial diaphragm prevents silicone-corneal contact in approximately 50% of aphakic eyes for at least 1 year.

Adolescent↗
PubMed1996

Histopathology of episcleral fibrosis after trabeculectomy with and without mitomycin C.

BACKGROUND: The aim of the study was to investigate the histopathologic features of scar tissue which have proliferated at the site of trabeculectomy of surgical failures after procedures with and without the use of the antimetabolite mitomycin C (MMC). METHODS: We obtained seven surgical specimens after trabeculectomy without MMC and five specimens after trabeculectomy with MMC, which were compared with 23 controls. Sections were stained with hematoxylin and eosin, Verhoeff-van Gieson, Grocott methenamine silver, and alcian blue. An immunohistochemical stain was performed for alpha-smooth muscle actin. RESULTS: Specimens from eyes operated without MMC showed dense scar tissue with many fibroblasts, much ground substance, parallel-oriented collagen fibers, and contractile intracellular proteins within the fibroblasts. Specimens from eyes operated with MMC consisted of tissue with only few fibroblasts which did not exhibit contractile proteins. Collagen fibers were arranged randomly with less ground substance. CONCLUSION: Even after 1-10 months, the scar tissue was distinctly different in the two groups. These results suggest that the use of MMC has long-term effects in vivo. Surgical failures related to scar formation are possible and not reduced to zero.

Actins↗
PubMed1996

Chronic basidiomycetous endophthalmitis after extracapsular cataract extraction and intraocular lens implantation.

BACKGROUND: Basidiomycetes are known as rare pathogens for meningitis, sinusitis, pneumonia, ulcerative lesions of the hard palate and onychomycosis. To our knowledge, no filamentous basidiomycete has been reported from a case of fungal endophthalmitis. PATIENT: We report on a 67-year-old man with delayed-onset endophthalmitis caused by an opportunistic basidiomycete. Tissue obtained during vitrectomy was cultured and examined by light and transmission electron microscopy. After enucleation the eye was examined by light microscopy. CONCLUSION: The patient had endophthalmitis from a sterile hyphomycete, harboured in remnants of lens capsule and a granuloma on the ciliary body. It was recognized as a Holobasidiomycete on the basis of its dolipore structure with perforated pore cap, seen with transmission electron microscopy. Species identification was not possible because fruiting bodies were absent. The patient failed to respond to intravitreal and systemic amphotericin B and systemic itraconazole. The eye was enucleated. This case demonstrates that filamentous basidiomycetes can cause endophthalmitis when inoculated during cataract extraction.

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