PubMed Health⌕ Search

Biomedical subjects

J M Schmidbauer

Publications and source records attributed to J M Schmidbauer.

At least 19 recordsLinked to original sources
PubMed2003

[Techniques for preparing postmortem human eyes to perform anterior segment intraocular surgery].

We describe different methods to prepare postmortem human or animal eyes used at the Center for Research in Ocular Therapeutics and Biodevices at the Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA. These techniques have been utilized for performing different surgical procedures (phacoemulsification, extracapsular cataract extraction, etc.), and for training of surgeons in-transition. Performing these techniques in the wet-laboratory contributed to improve surgical skills to perform the critical steps of the phacoemulsification surgery. Pathological evaluation of pseudophakic postmortem human eyes using the Miyake-Apple posterior view and histology was helpful to analyze postoperative complications of cataract surgery (anterior capsule opacification and posterior capsule opacification) secondary to postoperative proliferation of lens epithelial cells into the capsular bag. Modifications in the surgical techniques and/or lens design may be helpful to reduce these postoperative complications. Implantation of various aphakic and phakic intraocular lenses in postmortem human eyes as well as animal eyes was helpful to analyze the sizing and fitting of new lens designs within the eye.

Animals↗
PubMed2001

[Complication profiles of posterior chamber intraocular lenses IOL). An analysis of 586 foldable and 2077 rigid explanted intraocular lenses].

BACKGROUND: Foldable intraocular lenses (IOL) have become increasingly preferred choice for IOL implantation after cataract removal. However, both foldable as well as rigid IOLs are not yet complication-free and may need explanation. MATERIAL AND METHODS: A total of 2663 explanted posterior chamber IOLs (PCIOLs) were accessioned at the Center for Research on Ocular Therapeutics and Biodevices between January 1988 and September 2000. The lenses were examined grossly using a Leitz/Wild M-8-Zoom stereomicroscope. The clinical reasons for explanation were documented for foldable as well as for rigid lenses. RESULTS: Of a total of 2663 explanted PCIOLs, 586 were foldable lenses and 2077 were rigid PMMA lenses The most frequent reason for explantation of all 2663 IOLs studied was decentration/dislocation. Optic and haptic damage and posterior capsule rupture were significantly more often a reason for explantation in several foldable designs compared to rigid PCIOLs. Whereas rigid designs lead more often to corneal decompensation. The percentage of explanted IOLs because of inflammatory reactions decreased significantly from 1994 to 2000. CONCLUSIONS: The complication profiles of rigid and foldable IOLs revealed some apparent differences due to the nature of the IOL biomaterials and designs. IOL optic/haptic damage was a common complication for foldable IOLs, whereas it was only discovered in single digits for rigid PMMA IOLs. The possible explanation for this is, that the soft and flexible biomaterials, from which all the foldable IOLs were manufactured, are easier to be damaged during folding, unfolding and insertion procedure. In our opinion this relative disadvantage of foldable IOLs is by far outweighed by the numerous advantages of the small incision cataract surgery. The decreasing inflammatory reactions can be explained by advances in surgical techniques, especially the secure in-the-bag fixation of IOLs.

Humans↗
PubMed2001

[Morphological autopsy findings in human eyes implanted with Ridley intraocular lenses].

BACKGROUND: Sir Harold Ridley's first cataract extraction with implantation of an intraocular lens (IOL) marked the beginning of a major change in the practice of ophthalmology. MATERIAL AND METHODS: Two human autopsy globes implanted with original Ridley IOLs were grossly examined from behind with the Miyake-Apple photographic technique. The anterior segments were evaluated histologically. One Ridley IOL was examined by scanning electron microscopy. RESULTS: Both IOLs maintained a clear visual axis and had been placed in the capsular sac. The right lens was decentered inferiorly, the left IOL was well centered. The posterior capsule showed only minimal capsular opacification. Scanning electron microscopy (SEM) of the explanted IOL showed a smooth, well polished surface. CONCLUSIONS: In this patient Ridley IOLs maintained an ideal visual rehabilitation of 20/20 in both eyes, 22 and 18 years postoperatively. One surprising finding was the presence of a square, truncated optic edge geometry, very similar to that seen in some modern foldable IOLs. In our opinion the absence of posterior capsule opacification of the Ridley IOL may have partially been a result of this nearly sharp optic edge, that we confirmed by SEM. Even 22 years after implantation the Ridley IOL showed a high finish quality. Many of Sir Harold Ridley's early concepts like the IOL placement in the posterior chamber and endocapsular implantation are now the standard of modern cataract surgery.

Aged↗
PubMed2001

[Embolization of dural carotid cavernous sinus fistulas via the sylvian vein in 2 patients].

BACKGROUND: Dural carotid sinus cavernous fistulas account for about 12% of intracranial arteriovenous fistulas. These dynamic shunts are dilemmas not only for the clinical diagnosis but also for the management of ocular complications and in the application of diagnostic and therapeutic techniques. The traditional therapy is transarterial embolisation by an interventional neuroradiologist. We report on the management of two fistulas where the classical therapeutic methods were not possible or failed. PATIENTS AND METHODS: Two patients underwent an osteoplastic pterional craniotomy with cannulation of a vein of the sylvian fissure and controlled embolisation of the fistula with polyvinyl alcohol particles. RESULTS: Successful closure of both arteriovenous shunts was achieved on angiography with normalisation of clinical symptoms. As a severe complication one patient suffered from a stroke after the postoperative angiography. CONCLUSIONS: Arteriovenous fistulas not approachable by traditional therapeutic methods, can be embolised effectively via a superficial vein of the sylvian fissure. This surgical route should only be considered if other therapeutic ways fail or seem impossible.

Aged↗
PubMed2001

[Influence of surgery-related factors on the Nd:YAG laser capsulotomy rates of 3-piece silicone IOLs - analysis of 457 pseudophakic human globes obtained post mortem].

BACKGROUND: The purpose of this study was to analyze any possible surgical reasons which may have had caused posterior capsule opacification in 3-piece silicone IOLs that had required Nd:YAG laser treatment. Special attention was given to 1) quality of cortical clean up, 2) type of haptic fixation, and 3) continuous curvilinear capsulorhexis (CCC) size and shape. MATERIALS AND METHODS: Human eyes obtained post-mortem implanted with 3-piece silicone optic - PMMA haptic (SI 40 NB) and 3-piece silicone optic - Prolene haptic (SI 30 NB) designs IOLs, accessioned between January 1993 and December 2000 were evaluated by gross examination from behind under an operating microscope using the Miyake-Apple posterior photographic technique. The area and intensity of Soemmerring's ring and type of fixation was studied in 457 eyes. The mean diameter of the CCC and relation of the CCC edge to the optic rim were analyzed in 221 eyes. RESULTS: 1) The amount of Soemmerring's ring formation was significantly larger in the group of IOLs requiring Nd:YAG capsulotomy in both the SI 40 NB and SI 30 NB design than in the IOLs without capsulotomies. 2) The percentage of not in-the-bag fixated IOLs in both the SI 40 NB and SI 30 NB design was larger in the "Nd:YAG groups", without being statistically significant. 3) The "Nd:YAG groups" showed a significant higher amount of non overlapping clock hours of the CCC edge in relation to the optic rim. CONCLUSION: 1) The data confirm the clinical assumption that the incidence of PCO is correlated with the cortical clean up. 2) Our findings also support the clinical assumption, that poor IOL fixation increases the risk of PCO. 3) This study also verifies the relation of the CCC to PCO, namely a relatively small CCC covering the entire optic rim is best to reduce the Nd:YAG laser rate.

Cataract↗
PubMed2001

[Postoperative opacification of posterior chamber intraocular lenses - a review].

Postoperative opacification of intraocular lenses (IOLs) is a very unpleasant complication for the ophthalmic surgeon and the patient. We report on our experiences with opacification of different foldable IOL designs and rigid poly (methyl methacrylate) (PMMA) posterior chamber lenses.1. Snowflake degeneration of PMMA IOLs: This condition is an unanticipated and surprising late postoperative finding 8 to 15 years after implantation. In our opinion, this complication is probably not related to the PMMA biomaterial itself, but rather it appears to represent a manufacturing problem that has affected a selected, albeit large number of lenses manufactured in the 1980s-mid 1990s.2. Degeneration of UV absorber material and calcium deposits within the optic of hydrophilic IOLs: Two years postoperatively degenerations of UV absorber material and calcium deposits within the optic of single piece hydrophilic acrylic lenses SC60B-OUV manufactured by MDR (Medical developmental research Inc. Clearwater FL, USA) can occur. Although the precise mechanism is not fully known, it was assumed that these opacifications are due to premature aging of the UV blocking agent incorporated in the lens biomaterial and calcification.3. Calcification on the surface of the Bausch & Lomb Hydroviewtrade mark IOLs: Twelve to 15 months postoperatively granular surface calcifications in Hydroviewtrade mark IOLs occured. The mechanism is not fully understood. According to Bausch and Lomb studies, part of the components of the packaging contained silicone, which may have come off the packaging onto the lens optic, where it then appears to be a catalyst for calcium precipitation. The manufacturer has correlated a change in packaging with the appearance of the opacification. The manufacturer now believes that this problem has been solved. However, final verification will require a careful 1 - 2 years clinical study.4. Glistenings in the hydrophobic acrylic AcrySoftrade mark IOLs: The time frame of glistenings in the AcrySoftrade mark IOLs is highly variable. It has been suggested that the occurrence of glistenings may be related to variations in the temperature of the lens just prior to and or during insertion into the eye. Formation of vacuoles may occur within the submersed acrylic polymer when there is a transient increase and then decrease in temperature during the surgical procedure. "Glistenings" may then subsequently form by ingress of anterior chamber fluid. Contrast sensitivity can been decreased in some patients, but clinically significant decrease of visual acuity has been rare.

Biocompatible Materials↗
PubMed2001

[Millenniums update on posterior capsule opacification (PCO) scores, centration, biocompatibility and fixation of foldable intraocular lenses (IOL) - an analysis of 1,221 pseudophakic post mortem globes].

BACKGROUND: The ongoing and fast evolution of foldable IOL designs established the necessity to evaluate the different abilities of each lens style. The large IOL database (over 16,500 specimens) acquired in our laboratory, has permitted us to perform a clinico-pathological analysis on pseudophakic autopsy globes provided from sources worldwide, especially many Lions Eye banks in the United States. MATERIAL AND METHODS: We analyzed 6 foldable IOL styles commonly implanted in the United States, using one type of rigid IOL design (1-piece design rigid PMMA optics) as a comparison group. Posterior capsule opacification (PCO) score, decentration, fixation, presence or absence of a Nd:YAG laser posterior capsulotomy and area and intensity of Soemmerring's ring formation was discerned by examination under an operating microscope using the Miyake-Apple posterior photographic technique. RESULTS: The four lenses with the lowest rates ranging between 3.8 % and 21.7 % are modern designs, mostly implanted after 1992. The two lenses with the higher rates ranging between 23.1 % and 30.4 %, were all older designs, already prevalent prior to 1992. IOL fixation with both haptics in the capsular bag showed the best centration values and PCO scores. Our studies to date have shown in a preliminary fashion that the AcrySoftrade mark IOL displays the the lowest (best) biocompatibility score. CONCLUSIONS: Entering the new millenium, with evolution of modern surgical techniques and IOL designs, the incidence of the two major complications of cataract surgery, decentration and PCO are now finally diminishing.

Autopsy↗
PubMed2000

[Surgical transvenous embolization of spontaneous carotid cavernous sinus fistulas in two patients].

BACKGROUND: Arteriovenous communications in which blood flows from meningeal branches of the internal and external carotid arteries into the venous circulation around and in the cavernous sinus are termed spontaneous (dural) carotid sinus cavernous fistulas. Due to their mostly low shunt volume they are rarely life threatening, but without treatment they may cause severe ocular complications like episcleral secondary glaucoma, central vein occlusion or exudative retinal detachment. Traditional therapy is the transarterial approach by an interventional neuroradiologist. If such an approach is not possible or unsuccessful a transvenous route has to be considered. PATIENTS AND METHODS: Two patients underwent anterior orbitotomy via sub brow incision or infraciliary incision with cannulation of the superior ophthalmic vein or the inferior ophthalmic vein and embolization of the cavernous sinus with platinum coils. RESULTS: Successful closure was achieved on angiography and normalisation of clinical symptoms after a short period of progressive venous congestion. CONCLUSIONS: For arteriovenous fistulas that cannot be embolized arterially the surgical transvenous orbital route may work as a method of second choice. When performed by an interdisciplinary team (orbital surgeon, interventionell neuroradiologist) it is a technically straightforward, effective and promising approach.

Aged↗
PubMed2000

[Hereditary occlusive cerebroretinal vasculopathy in two sisters].

BACKGROUND: Retinal microvascular abnormalities associated with multiorgan disease may be observed in a number of systemic illnesses and syndromes. PATIENTS: Two sisters with identical signs of a hereditary cerebroretinal vasculopathy (occlusive retinal angiopathy--cerebral vasculopathy--microcephalus) were treated at the University Hospital of Saarland. COURSE: Photocoagulation for treatment of neovascular complications secondary to retinal ischemia was performed. In one eye a vitrectomy became necessary because of persistent vitreal hemorrhage. One sister died because of non treatable intracranial hypertension at the age of 22 years. CONCLUSIONS: Interdisciplinary work-up is important in patients with cerebroretinal disease. Neuropathologic evaluation including brain biopsy and neuroimaging plus ophthalmoscopy and pedriatic findings lead to the diagnosis of this rare hereditary, in this case most likely autosomal recessive condition. Photocoagulation may limit neovascular complications secondary to retinal ischemia. A specific form of treatment has, however, not yet been found.

Adult↗
PubMed2000

[Ocular injuries and triage after the bombing attack on the United States embassy in Nairobi (Kenya)].

BACKGROUND: As a result of the terrorist bombings of the United States Embassies in Daressalam (Tansania) and Nairobi (Kenya) on August 7, 1998, over 200 people were killed. 5000 persons were injured severely. The purpose of this article is to provide a review of our experiences in the evaluation and treatment of patients with multiple simultaneous ocular injuries sustained in the Nairobi attack. PATIENTS AND METHODS: We treated eight survivors of the assault, four of them with extremely severe eye injuries. A three-tiered system of triage developed. The first level occurred on scene, in which minor injuries were treated locally and more severe injuries were transported by aeromedical evacuation to Landstuhl Regional Medical Center (LMRC), in Germany among other locations. Surgical exploration of all patients arriving at LRMC was performed and surgical repair was undertaken when appropriate and technically possible. Patients requiring vitreoretinal surgery were transferred either to Saarland University Eye Hospital, Homburg, Germany, or Walter Reed Army Medical Center, Washington, DC. RESULTS: Only one eye required enucleation, due to an almost complete extrusion of the retina. It was possible to stabilize even severely injured eyes with multiple intraocular foreign bodies. CONCLUSIONS: Modern microsurgical techniques such as temporary keratoprothesis, perforating keratoplasty, and pars plana vitrectomy can now save eyes and often allow restoration of usuable visual acuity where this once have been deemed impossible.

Adult↗
PubMed2000

[Driving ability after reversal of phenylephrine 10% induced mydriasis by dapiprazole 0.5%; a prospective study on 65 eyes].

BACKGROUND: Particularly outpatients want to reach the ability for driving a car as soon as possible after pupillary dilatation. Dapiprazole is an alpha-1 adrenergic inhibitor that antagonizes the mydriatic effect of phenylephrine in a direct competitive way. The aim of this study was to determine restoration of traffic related functions after dapiprazole application in accordance with the guidelines of the German Society of Ophthalmology (DOG). SUBJECTS: 65 eyes of 33 subjects were tested (17 females, 16 males). All had driving licenses without restrictions. Before mydriasis and after reversal with dapiprazole traffic-related functions were evaluated (photopic visual acuity, mesopic vision, sensitivity to glare, colour vision, accommodation, visual field). RESULTS: No relevant changes of the parameter responsible for the ability to drive a motor vehicle could be shown after reaching premydriatic pupil diameters. CONCLUSIONS: There is evidence that reaching normal pupil diameters after reversal of mydriasis by dapiprazole is a valid sign of restoration of traffic related functions.

Adolescent↗
PubMed1998

[Early trans-sphenoid decompression in indirect traumatic optic neuropathy].

BACKGROUND: Indirect traumatic optic neuropathy represents a severe, potential vision-threatening disease process that requires close interdisciplinary cooperation for treatment. In general, any therapy has been discussed controversially in the literature. Based upon experiences with spinal cord trauma, high-dose steroid therapy is recommended initially to minimize secondary consequences following orbital trauma. The usefulness of surgical decompression of the optic nerve has been confirmed in several studies but is still not recommended in principle. PATIENTS AND METHOD: In nine consecutive patients with known indirect traumatic optic neuropathy and marked losses of vision, transsphenoidal optic decompressions were carried out with simultaneous systemic megadose steroid therapy. RESULTS: A postoperative increase in visual acuity from 1/35 to 10/20 occurred in five patients, while no improvement in visual acuity could be achieved in the other four patients. DISCUSSION AND CONCLUSION: Previous reports have indicated that some authors will not recommend surgical decompressions if a loss of sight or no light perception occurs directly after an accident. This situation was seen in seven of our patients. The visual acuity of four patients remained no light perception in spite of surgical treatment. In three other patients, an increase in visual acuity from amaurosis improved to 1/35, 4/20 and 8/20, respectively, following early decompression combined with steroids. This experience together with the positive results of other studies supports carrying out decompressions of the optic nerve, even when an amaurosis occurs directly after trauma.

Adolescent↗
PubMed1996

[Antiproliferative therapy with 5-fluorouracil in erbium:YAG laser sclerostomy ab externo].

BACKGROUND: Erbium laser sclerostomy (ELS) ab externo is a minimally invasive addition to conventional fistulating glaucoma surgery. To date, the success rate of this method is lower than that of trabeculectomy or goniotrepanation. The chief cause of therapy failure is postoperative episcleral scarring of the bleb. It was the aim of the present study to decrease the occlusion rate of this complication. PATIENTS AND METHODS: 41 eyes were treated with subconjunctival injections of 5-fluorouracil perioperatively to an intended total dose of 40 mg to prevent episcleral scarring. At the same time, bigger probe diameters were used (550 microns and 700 microns instead of 300 microns). RESULTS: After 3 months, the proportion of patients with regulated intraocular pressure after using bigger probe diameters combined with anti-proliferative therapy was significantly higher (550 microns fiber +5-FU: 73%; 700 microns fiber +5-FU: 71%) than for a 300 microns fiber without 5-FU (38%). Average intraocular pressure in successful cases was 11.6 +/- 4.2 mmHg in the 550 microns fiber +5-FU group and 12.3 +/- 4.0 mmHg in the 700 microns fiber +5-FU group. CONCLUSION: The short-term results of erbium laser sclerostomy as a minimally invasive technique can be improved by using increasing laser fiber diameters and by perioperative injections of 5-FU to prevent episcleral fibrosis.

Antimetabolites↗