[Viscoelastic properties of human capsular sac contents].
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Accommodation, Ocular↗
Biomedical subjects
R Guthoff
Publications and source records attributed to R Guthoff.
[Confocal in vivo microscopy after 15 mm sclerocorneoplasty à chaud in necrotizing keratitis].
BACKGROUND: Confocal microscopy allows an in-vivo visualization of corneal structures in frontal optical sections. By means of this method we show morphological changes in a corneal transplant after sclerocorneoplasty à chaud because of a necortizing keratitis. CASE REPORT AND METHOD: We report on a patient who had to undergo a 15 mm diameter sclerocorneoplasty à chaud because of a necrotizing keratitis of his right functionally last eye in October 1993. Five months after transplantation there was a circular vascularization of the scleral rim and a progressive crystalline deposition in the periphery of the cornea. The main part of the donor cornea remained clear with a vision of 0.6. After one year the patient had developed a mature complicated cataract and got a phacoemulsification with a tunnel in the transplanted cornea and an implantation of a posterior chamber lens. In May 1995 the visual acuity was 0.9. We examined the epithelium, stroma and endothelium of the graft by means of in-vivo confocal slit scanning microscopy. RESULTS: All layers of the cornea are demonstrated. There were crystalline needle-like structures in the peripheral stroma and round cystic bodies in the deep stroma. Nerves were visible one year after transplantation. The endothelial cells showed a mild polymorphism and still a density of 2200 cells/mm2. CONCLUSIONS: Confocal microscopy is a useful non invasive technique for routine examinations after keratoplasty. Microscopical changes in the tissue are also visible in case of absent postoperative complications. With growing knowledge the confocal microscopy will give more insight into processes of wound healing.
Aged↗
[Ultrasound biomicroscopy imaging of accommodative configuration changes in the presbyopic ciliary body].
Direct observation of the position of the ciliary body was possible only in cases of gross anatomic, and probably also functional, abnormalities. Utilizing the 50 MHz ultrasound biomicroscope, we investigated the profile changes of the ciliary body in ten eyes of ten patients, ranging in age from 54 to 86 years while they were ocusing on a target at a distance and afterwards on an object up close. After electronic image processing of ten single video pictures from each accommodative status, a summarized picture for every accommodative status was obtained. In seven of ten cases, during accommodation a remarkable shift of the ciliary body was observed anterior to the iris and in the direction of the lens equatore, while the iridociliary body contact zone became wider in five of the ten eyes. Ultrasound biomicroscopy allows visualization of the dynamics of the accommodative process. As the human ciliary body does not lose its contractility in the senium, the loss of accommodation in presbyopia is mainly caused by age-related changes of the lens and capsula.
Accommodation, Ocular↗
An adjuvant afterloading brachytherapy device for use after orbital exenteration in patients with orbital malignancies.
In cases of malignant diseases situated within the orbit and threaten to extend beyond it, removal of the orbit and periorbital contents may be indicated, followed by adjuvant chemotherapy or irradiation. An effective radiotherapy device for treatment of residual or suspicious cancer in the enucleated orbit consists of an external-beam radiation source (60Co) and an intraoperatively fitted mould as a guide for the flexible afterloading tubes using a 192Ir source. Considering the physical dose distribution and the local situation, this therapy permits a high dose with homogeneous dose distribution to the target area of the orbit but also allows significant dose reduction to adjunctive critical structures. Four patients with different orbital malignancies were treated by means of a combination of percutaneous radiotherapy with afterloading brachytherapy following orbital exenteration. The individual mould of the orbital cavity is modeled at the end of the operation. The technique of radiotherapy, dose distribution, and follow-up of the disease are demonstrated. Orbital malignancies with an extremely poor prognosis may profit from the application of this combined radiotherapy to avoid supraradical surgical intervention.
Adenocarcinoma↗
Corneal reinnervation following penetrating keratoplasty--correlation of esthesiometry and confocal microscopy.
Thus far assessment of corneal reinnervation after penetrating keratoplasty has been possible only by esthesiometry techniques. Since the introduction of confocal microscopy, we have been capable of performing structural corneal in vivo examinations. The purpose of our study was to correlate esthesiometry results with confocal microscopy findings. We used a Cochet-Bonnet esthesiometer and a Microphthal confocal microscope to investigate corneal grafts in vivo. A total of 46 eyes were examined preoperatively and for up to 3 years after penetrating keratoplasty. At 8 weeks after keratoplasty the first stromal nerves were detected in the periphery of the graft. The first nerves in the middle and superficial stroma of the graft center were observed at 7 months after surgery. Reinnervation of the central basal epithelium was found at 2 years after keratoplasty. The highest level of sensitivity was detected in young patients with reinnervation of the basal epithelium. Confocal microscopy enables us to correlate morphologically and functionally corneal reinnervation after surgery. The present study shows that corneal reinnervation is influenced by the amount of time elapsing after surgery, the patient's age, and the preoperative diagnosis. In none of our patients was normal nerve morphology or sensitivity observed during the follow-up period. Comparison of the morphology of nerves seen in eyes after nonsurgical trauma with that observed in corneal grafts indicates that surgically induced scar formation may limit nerve regeneration in grafts.
Adolescent↗
Confocal in vivo microscopy and confocal laser-scanning fluorescence microscopy in keratoconus.
The purpose of this study was the determination of morphological changes in the corneal epithelium and the keratocyte network in keratoconus. In all, 33 eyes of 19 patients were examined in vivo using the confocal slit-scanning microscope Microphthal. After penetrating keratoplasty, recipients' trephanates were stained with the Live/Dead kit and examined using the confocal laser-scanning fluorescence microscope Diaphot 300/Odyssey. The fluorescence images were reconstructed three-dimensionally. All findings were compared with data from healthy corneas. Morphological alterations were found only in the area of the corneal apex; obviously elongated superficial epithelial cells arranged in a whorl-like fashion were found. Near Bowman's membrane, highly reflective changes and fold-like structures were visible. The anterior stroma also showed an increased reflectivity. In the posterior stroma, typical findings were Vogt's striae and keratocytes with extremely long processes arranged nearly in parallel. In scarred stroma the keratocytes were spindle-shaped and arranged irregularly. The spatial organization of the living keratocyte network could be demonstrated through three-dimensional reconstructions.
Adult↗
Assessment of corneal alterations following laser in situ keratomileusis by confocal slit scanning microscopy.
This investigation was done to evaluate in vivo changes in corneal micromorphology occurring after laser in situ keratomileusis. By means of confocal microscopy, nine eyes of eight patients showing uncomplicated wound healing at 2-16 weeks after surgery and one eye of one patient at 30 weeks after initial surgery who had to undergo two retreatments because of a central island were examined. Video recording was used to register the data. The distribution of scattered light in the treated corneae was registered with the z-scan of the microscope. Slit-lamp findings obtained several weeks postoperatively showed only minor corneal alterations. Confocal microscopy revealed morphological changes as a result of the surgery, especially in the epithelium and in the anterior stroma. With the z-scan an additional peak determined by higher reflectivity in the anterior stroma was found. The retreated patient showed marked folds in the area of the interface and flap. Confocal in vivo microscopy is suitable for the noninvasive detection of micromorphological alterations following refractive corneal surgery and for observation of the postsurgical wound-healing phase, including nerve regeneration.
Adult↗
Correlation of histological tumor vascularization and Doppler sonography in patients with malignant melanoma of the choroid.
BACKGROUND: In previous studies Doppler sonography was proven to the useful for diagnostics and follow-up of malignant melanomas of the choroid. METHODS: To evaluate the correlation between Doppler sonographical findings and the histological tumor vascularization, we examined five eyes of five patients with malignant melanoma of the choroid before enucleation with an ATL Ultramark-8 Duplex scanner and compared these results with computerized planimetry of histological tumor vascularization after immunohistochemical staining of vascular endothelium with anti-factor-VIII antibodies. RESULTS: We found no definite correlation of flow velocities with histological parameters of tumor vascularization. The tendency was for a decrease in maximum flow velocities as histological vascularization increased. CONCLUSIONS: Due to (1) the usual lack of sensitivity parameters of the used Duplex device for the clinical user and (2) the unpredictable branching pattern within a melanoma resulting in an unknown angle of incidence of the Doppler beam, we conclude that the quantitative results of Doppler sonography require cautious interpretation. Nevertheless, presence or absence of Doppler shifts is a valuable parameter for the follow-up of irradiated tumors.
Blood Flow Velocity↗
[Computer program for improved diagnostic coding in ophthalmology based on the expanded ICD 10].
BACKGROUND: The coding of ophthalmological diagnoses is a long-standing problem that has recently been highlighted by the planned introduction of ICD 10. METHODS: Using an alphanumerical classification system for the first time, ICD 10 offers the space needed for necessary expansion without leading once again to dislocations in the numbering system. The FoxPro 2.5 database system was used to create a program based on an expanded ICD 10 that can be applied from DOS and Windows. RESULTS: ICD 10 was expanded by the addition of a numerical fifth digit, thus increasing the number of classifiable ophthalmological disorders by a factor of 4.2 from 390 to 1635. The new program greatly facilitates the handling of this substantial amount of data. CONCLUSIONS: The enhanced diagnosis coding achieved with the expanded ICD 10 permits nosologically exact statistics to be kept for use as a basis for further scientific work.
Data Display↗
[Continuous ultrasound biomicroscopic imaging of accommodative changes in the human ciliary body].
BACKGROUND: Slitlamp observations of the position of the ciliary body behind the iris root are possible only in cases of gross anatomic, and probably also functional, abnormalities. This study was performed to investigate physiological changes of the human ciliary body configuration during accommodation. MATERIAL AND METHODS: We used the 50 MHz ultrasound biomicroscope to measure the ciliary body changes in 5 left eyes of normal subjects during accommodation, while the right eye, wearing corrective spectacles, focussed Snellen letters at a distance of 3 m. For desaccommodation plus lenses were utilized, while negative lenses were applied to blur vision as a stimulus for accommodation. During postprocessing the best images of the video sequence were recalled on a monitor and the profile of the ciliary body was manually drawn on a transparent folder. For interpretation we used a projection system with vector analysis. RESULTS: During accommodation there is a shift of the ciliary body anteriorly toward the scleral spur and in the direction of the lens equator. In 4 out of 5 eyes a contact between the ciliary body and the posterior iris surface could be demonstrated. There was a measurably widening of the anterior chamber angle in 3 out of 5 eyes. CONCLUSIONS: Ultrasoundbiomicroscopy seems to be a way for assessing ciliary body deformation during accommodation. Our results are in accordance with histologic and gonioscopic findings and confirm biomechanical theories of the accommodation process. Further investigations including online digital image processing will be necessary to evaluate accommodation in its complexity.
Accommodation, Ocular↗
[Visualization of keratocytes in the human cornea with fluorescence microscopy].
There is little information about the state of human keratocytes in longterm cornea storage and the influence of these cells on the survival of the corneal transplant after keratoplasty. Up to now stromal keratocytes have not been taken into consideration in regard to the culture conditions in cornea banking. Therefore, a method was used, first described by Poole et al., who stained porcine corneas using the Live/Dead-Assay (Molecular Probes Inc.). After staining porcine and human corneal slices with the fluorogenic substance calcein AM and the fluorochrome ethidium homodimer, we examined the fluorescing cells to acquire more knowledge about the density, morphology and vitality of human keratocytes. Living cells are distinguished by the presence of ubiquitous intracellular esterase activity, determined by the enzymatic conversion of the virtually non-fluorescent cell-permeant calcein AM to the intensely fluorescent calcein, producing an intense, uniform, green fluorescence in living cells. Ethidium homodimer enters cells with damaged membranes and undergoes a 40-fold enhancement of fluorescence on binding nucleic acids, thereby producing a bright red fluorescence in dead cells. The examinations were performed using a conventional fluorescence microscope and a confocal slit scanning microscope. Like in the porcine corneas, we found three keratocyte subpopulations in the human corneas, but there were some differences in morphology and patterns of staining between the two species in the central and posterior stroma. After long periods of cornea storage we found signs of cell degeneration like loss of cytoplasmic processes and an increasing number of dead cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Binocular photometer for measuring light perception in diseases of the visual pathway].
In patients with a reduction in visual function because of optic nerve neuritis, light sensitivity is tested to detect differences between the right and left eye in combination with the swinging flashlight test and visual evoked potential (VEP). A binocular Zeiss microscope was modified to use integrated photometer-controlled binocular stimulus fields and a central light system for fixation and variation of the contrast (background illumination). For exact binocular measurements of light sensitivity on both eyes, electronically controlled test fields (visual angle 5 degrees-20 degrees) guarantees only macular or overfoveolar stimulation. In addition, splitting the light for each stimulus field from only one halogen lamp guarantees wave-length-independent testing. Patients with various retinal diseases and neuritis nervi optici pathology were examined using pattern VEP, testing of the absolute lower threshold of light sensitivity, and binocular comparison over the range of luminous density. This binocular optical photometer system allowed minimal differences to be identified in the present visual function and after the eye had recovered from optic nerve neuritis.
Evoked Potentials, Visual↗
[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↗
[Ultrasound biomicroscopy for evaluation of space-occupying lesions of the anterior eye segment. Initial results].
Pavlin's group developed the ultrasound biomicroscope, and it has been in use since 1990. It is an ultrasound method working at high frequencies between 40 and 100 MHz. It is possible to resolve structures up to approximately 50 microns in size at a maximal depth of 5 mm. We examined about 80 patients with tumors in the anterior segments of the eye, mainly in the iris and the ciliary body. Good differentiation between cystic and solid space-occupying lesions is possible to say whether or not is malignant.
Adult↗
Inflammatory pseudotumor of the anterior orbit. A symptom in allergic granulomatous angiitis (Churg-Strauss syndrome).
Allergic granulomatosis accompanied by angiitis (Churg-Strauss syndrome) constitutes an unusual disorder which is characterized clinically by bronchial asthma and hypereosinophilia, accompanied by systemic symptoms of histopathologically and by necrotizing vasculitis, extravascular granulomas and tissue infiltration by eosinophils. We report a case of a 4 year-old child presenting with acute pneumonia and deteriorated general condition. The biopsy of an inflammatory pseudotumor of the right anterior orbit revealed necrotizing vasculitis, extravascular epitheloid granuloma and eosinophilic tissue infiltration. These are characteristic changes of allergic granulomatous vasculitis (Churg-Strauss syndrome. Laboratory findings were characterized by blood eosinophilia, increased IgE value and the presence of antineutrophil cytoplasmic ant antibodies (p-ANCA). Local and systemic manifestations quickly regressed after parenteral application of corticosteroids. Two exacerbations of inflammatory pseudotumor occurred after reduction of the corticosteroid dosage. Systemic vasculitic syndromes are rare in childhood. Orbital manifestations in Churg-Strauss syndrome in childhood have never been reported.
Biopsy↗
[44th Congress of the Northwest German Society of Ophthalmologists at the Rostock University, 3 to 4 June 1995].
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Ophthalmology↗
[Clinical decision aids using ultrasound biomicroscopy].
Ultrasound biomicroscopy (UBM) allows high-resolution imaging of the anterior segment due to ultrasound transducers between 50 and 100 MHz. At present stage of experience, mainly analysis of iris and ciliary body structures seem to be clinically rewarding. This is demonstrated by two similar looking tumors, involving the chamber angle. By means of UBM it was possible to differentiate between cystic and solid growths and to assess tumor extensions.
Adult↗