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Biomedical subjects

H Hoerauf

Publications and source records attributed to H Hoerauf.

At least 19 recordsLinked to original sources

Treatment of central retinal vein occlusion by radial optic neurotomy in 107 cases.

BACKGROUND: To evaluate the potential role of radial optic neurotomy (RON), a new surgical technique has been recently proposed for treating central retinal vein occlusion (CRVO). It is hypothesized that CRVO constitutes a neurovascular compartment syndrome at the site of the lamina cribrosa, which can be alleviated by performing a radial incision at the nasal part of the optic nerve head, relaxing the cribriform plate and the adjacent sclera. METHODS: One hundred and seven patients were treated with RON for CRVO at five collaborating ophthalmologic centers. All patients were evaluated by a standardized protocol. For analysis of the angiographic and fundus findings, reference images were used. Intraoperative and postoperative complications were reviewed. RESULTS: On 55 right and 52 left eyes of 107 patients (55.6% male, 44.4% female) with a median age of 68 years (range 21-91 years), RON was performed. The median follow-up time was 6 months (range 1-24 months). The median preoperative visual acuity (VA) was 0.05 (logMAR 1.3), increasing to a median postoperative VA of 0.08 (logMAR 1.1). Patients with an interval of more than 90 days between RON and onset of CRVO showed no significant change in VA at the 6-month follow-up. Severe peripapillary swelling of the optic nerve head prior to RON resulted in an average increase of 4.2 lines in VA at the 6-month follow-up. Angiographic findings of shunt vessels were seen in 18/30 cases after 12 months and were accompanied by an average improvement of VA of six lines. Visual field tests showed various defects in 86.8% of all cases. In one patient an iatrogenic injury of the central retinal artery occurred (0.9%). CONCLUSION: Despite the potential risk of visual field defects, RON seems to be a quite safe procedure. The majority of patients showed rapid normalization of the morphologic fundus findings, with an improvement in VA uncommon for the natural history of CRVO. No significant change in VA was seen in patients with an interval of more than 90 days between the onset of CRVO and RON. A prospective study is warranted for further investigation.

Adult↗

Detection of Treponema pallidum in the vitreous by PCR.

BACKGROUND: Ocular involvement of syphilis still poses a clinical challenge due to the chameleonic behaviour of the disease. As the serodiagnosis has significant limitations, the direct detection of Treponema pallidum (TP) in the vitreous represents a desirable diagnostic tool. METHODS: Real-time polymerase chain reaction (PCR) for the detection of TP was applied in diagnostic vitrectomies of two patients with acute chorioretinitis. Qualitative verification of TP by real-time PCR and melting point analysis according to a modified protocol was ruled out. Patients underwent complete ophthalmological examination with fundus photographs, fluorescein angiography, serological examination, antibiotic treatment and follow-up. RESULTS: In two cases of acute chorioretinitis of unknown origin, real-time PCR of vitreous specimens of both patients provided evidence of TP and was 100% specific. Initial diagnosis of presumed viral retinitis was ruled out by PCR of vitreous specimen. Patients were treated with systemic antibiotics and showed prompt improvement in visual function and resolution of fundus lesions. CONCLUSIONS: With real-time PCR, detection of TP in the vitreous was possible and delivered a sensitive, quick and inexpensive answer to a disease rather difficult to assess. In cases of acute chorioretinitis, the use of PCR-based assays of vitreous specimens in the diagnostic evaluation of patients is advisable. Although syphilitic chorioretinitis is a rare disease, PCR should include search for TP, as diagnostic dilemmas prolong definitive treatment in a sight-threatening disease.

Adult↗

Real-time imaging of transscleral diode laser cyclophotocoagulation by optical coherence tomography.

PURPOSE: To present optical coherence tomography (OCT) for real-time imaging of cyclophotocoagulation effects. METHODS: In a pilot study, real-time transscleral OCT images were generated during diode laser cyclophotocoagulation in four eyes of four patients suffering from uncontrolled glaucoma using a specially designed contact applicator containing the OCT fiber, a focussing fiber optic and the fiber of the diode laser. RESULTS: When the contact system was used, two layers could be differentiated: a superficial thick hyperreflective complex representing conjunctiva, Tenon's capsule, episclera and sclera, and a thinner hyporeflective layer representing the ciliary body. During cyclophotocoagulation, real-time OCT showed a clear and sudden thickening of the ciliary body in the treated area. CONCLUSION: This new OCT device represents a first step towards visual, real-time imaging of cyclophotocoagulation. After further adaptation of the delivery system, further trials are needed to correlate OCT findings with aqueous production and intraocular pressure.

Ciliary Body↗

Secondary paracentral retinal holes following internal limiting membrane removal.

AIM: To report on a new postoperative finding after delamination of the internal limiting membrane (ILM) for the treatment of different macular pathologies. METHODS: Seven patients are described with paracentral retinal holes, all located temporally to the macula, which developed after pars plana vitrectomy and uncomplicated ILM removal for cystoid macular oedema (n = 3), macular pucker (n = 3), and macular hole (n = 1) with the use of indocyanine green (n = 4), trypan blue (n = 1), triamcinolone acetonide (n = 1), or without dye (n = 1). CONCLUSION: The use of dyes has been incriminated in causing iatrogenic damage to the retina. In this series, the new observation of retinal holes in the macular area is thought to be related to the removal of the ILM itself. The authors speculate that ILM delamination may cause a retinal weakening by Müller cell damage; this may be followed by a structural breakdown and, consequently, hole formation.

Adult↗

[The influence of a new surface treatment of silicone intracoular lenses with fluoralkylsitan on the adherence of endophthalmitic bacteria in vitro]].

INTRODUCTION: Dynasilan is a fluoroalkylsilan which is able to bind to surface active molecules of intraocular lenses (IOLs), thereby offering a new option for surface modification of silicone lenses. The purpose of this in vitro study was to investigate the influence of this new surface treatment on the adherence of two typical endophthalmitis-inducing bacteria ( Staphylococcus epidermidis, Propionibacterium acnes). MATERIALS AND METHODS: A total of 14 Dynasilan-treated and 14 untreated silicone lenses were incubated at 37 degrees C for 24 h in brain heart infusion broth (10(8) CFU/ml) either with Staphylococcus epidermidis or with Propionibacterium acnes for 1 h. Subsequently, the adherent bacteria were resuspended using ultrasonification at 35 kHz for 3 x 45 s. After a dilution series and incubation at 37 degrees C for 24 h or 3 days the colonies were counted. RESULTS: On untreated IOLs incubated with Staphylococcus epidermidis the average number of bacteria was 3.6 x 10(7)/ml, and on treated IOLs the number of counted colonies was reduced to 1.09 x 10(7)/ml. Incubated with Propionibacterium acnes the average number of adherent bacteria on untreated IOLs was 4.75 x 10(4)/ml and on modified IOLs the number was reduced to 2.94 x 10(4)/ml. CONCLUSION: Dynasilan surface treatment may reduce the adherence of Staphylococcus epidermidis and Propionibacterium acnes on silicone intraocular lenses. Further studies regarding the stability of this treatment, its biocompatibility and influence on lens epithelial cell adhesion are in progress.

Bacterial Adhesion↗

[Vitreous body floaters and vitrectomy with full visual acuity].

PURPOSE: To evaluate the role of vitrectomy in patients with visually disturbing vitreous body floaters and full visual acuity (VA). METHODS: A total of 9 eyes from 8 patients (2 female, 7 male, median age 57 years) with a preoperative VA of 1.0 were analysed retrospectively. The median duration of symptoms was 12 months. In all eyes a pars plana vitrectomy was performed. The median follow-up period was 13 months. RESULTS: No intraoperative or postoperative complications were observed. In all patients vision improved subjectively and objective VA remained unchanged. In 2 out of 5 phacic patients a cataract extraction was performed during the follow-up period. CONCLUSIONS: In a selected group of patients vitrectomy can improve subjective vision even in eyes with full objective VA. A critical patient selection with respect to psychological criteria and the individual risk of vitrectomy is extremely important.

Adult↗

[Retinal photoablation with the Erbium:YAG laser. Initial experimental results for traction-free removal of tissue].

BACKGROUND: To investigate the potential of an Er:YAG laser for precise and traction-free removal of retinal layers in vitro. MATERIAL AND METHODS: Retinal ablation in porcine retinal explants was performed using a free running Er:YAG laser focused either into a low-OH quartz fiber or a sapphire fiber. The explants were treated under air or perfluorodecaline (PFD). The ablation depth was evaluated by optical coherence tomography (OCT) and histology sections. RESULTS: A radiant exposure of 5.0 J/cm(2) under air and PFD resulted in complete transsection of the neurosensory retina. Between 3.5 and 2.0 J/cm(2) the ablation depth and the defect patterns varied markedly and adjacent thermal zones areas were seen. Below 2.0 J/cm(2) no defects could be created in air, whereas under PFD the ablation extended into the ganglion cell layer. Ablations using a sapphire fiber and 2.0 J/cm(2) showed a significantly higher reproducibility of ablation depth, and homogeneous defect patterns limited to the nerve fiber layer could be produced without thermal damage. CONCLUSIONS: The Er:YAG laser system with a low-OH quartz fiber allowed ablation of inner retinal layers in vitro, but revealed a variable ablation depth and low reproducibility.However, a sapphire fiber showed markedly improved results. Therefore its use during vitreoretinal surgery seems possible not only as a cutting device but also as a tool for the ablation of fine retinal structures.

Animals↗

[Conventional ablation surgery or primary vitrectomy in complicated retinal holes].

BACKGROUND: We retrospectively evaluated 100 difficult cases out of 803 consecutive eyes with retinal detachment in order to determine the best surgical procedure in cases with difficult break configurations such as multiple, large, and central holes. METHODS: We treated the eyes either with conventional buckling surgery (n = 60) encircling buckle (EB) plus sponge exoplant (SP) (n = 45) or multiple sponge exoplants (n = 15) or with primary vitrectomy (PV) (n = 40). From the 40 patients in the PV group, 10 underwent vitrectomy plus intraocular gas only, in the other cases an encircling band was used (n = 30). RESULTS: In the EB/SP group the retina was attached directly after surgery in 59/60 cases. During a mean follow-up of 14.5 months redetachment occurred in 4/60 cases. In the PV group the retina was attached in 37/40 cases after resorption of gas and during the mean follow-up of 9.3 months redetachment occurred in an additional 4/40 cases. Complications during surgery in the EB/SP group were retinal incarceration (n = 2) and subretinal hemorrhage (n = 2). In the PV group intraoperative complications included choroidal detachment (n = 1) and iatrogenic holes (15%). Postoperative complications were choroidal detachment in 6/60 vs 0/40, transitory increased intraocular pressure (30% vs 68%). Double vision, however correctable by means of prisms, occurred in 4/60 vs 0/40. CONCLUSIONS: The primary attachment rate is high and similar with both procedures. The spectrum of intra- and postoperative complications is however different between both groups.

Aged↗

[Examination of the cornea using optical coherence tomography].

INTRODUCTION: This study evaluated the clinical use of optical coherence tomography (OCT) for two-dimensional representation of the cornea. PATIENTS AND METHODS: Noncontact slitlamp-adapted OCT was used in selected cases to evaluate pathologically altered corneas and to measure the central corneal thickness and curvature. RESULTS: OCT provided correlation between differences in reflection and morphological changes. Scar tissue resulted in hyper-reflective light scattering, whereas cystic lesions were hyporeflective. Precise biomorphometry also allowed representation of intrastromal and retrocorneal changes. Central corneal thickness measured by OCT yielded reproducible values and corneal curvature could be calculated from the optical signals of the corneal surface. CONCLUSIONS: OCT provides high-resolution representation of the cornea and exact evaluation of its morphology, thickness, and curvature. Due to the noncontact, simple, and rapid examination using the slitlamp the corneal OCT method is a promising additional diagnostic modality.

Adolescent↗

Combined use of partially fluorinated alkanes, perfluorocarbon liquids and silicone oil: an experimental study.

BACKGROUND: Partially fluorinated alkanes (FALKs) are a new class of substances which can be used in vitreoretinal surgery as an intraoperative tool and as a long-term tamponade. The aim of this in vitro study was (1) to investigate the solubility of FALKs in silicone oil during direct exchange, (2) to study their combined use and solubility in PFCLs, (3) to evaluate their lipophilic properties and (4) to investigate the possibility of preparing "heavy silicone oil". METHODS: (1) Four different FALKs (F6H6, F6H8, O44 and O62) were directly exchanged with silicone oil (5,000 mPas). The dissolved amount of fluorocarbons in the removed silicone oil was determined by gas chromatography and by gravimetry. Furthermore, the diffusion phenomena during the exchange process were studied. (2) The behaviour of FALKs in PFCLs was investigated and the solubility of the resulting mixtures in silicone oil was measured. (3) The solubility of FALKs and PFCLs in native olive oil was analysed. (4) Different FALKs were added to silicone oil and measurements of the resulting specific gravity and the viscosity were performed. RESULTS: (1) FALKs dissolved in silicone oil up to the following values: F6H6=45 m%, F6H8=54 m%, 044=100 m%, O62=18 m%. (2) FALKs dissolved in PFCL, thereby changing the physicochemical properties of PFCL depending on the type of FALK and ratio used. (3) The lipophilic properties of FALKs and PFCLs could be characterized by their dissolution in native olive oil (F6H8=23.4 m%, 044=16.7 m%, F6H6=12.3 m%, 062=5.3 m%, PFD=1.1 m%, PFO=0.6 m%). (4) It was possible to prepare "heavy silicone oil" e.g. by adding 30 vol% F6H8, resulting in a specific gravity of 1.08 g/ml, or by adding 80 vol% 044, resulting in a specific gravity of 1.25 g/ml, but decreasing the viscosity of the mixtures dramatically. CONCLUSION: (1) If FALKs are used as an intraoperative tool, a direct exchange with silicone oil should be avoided owing to their capacity to dissolve in silicone oil, resulting in a mixture with unpredictable properties. (2) A combined use with PFCLs and silicone oil is possible, if the right ratio is chosen. (3) The solubility of FALKs in native olive oil may be an indicator for their tissue penetration and may render feasible their use as a long-term tamponade. (3) "Heavy silicone oil" preparation using FALKs is possible, but the mixture needs further evaluation in terms of emulsification, mobilization of oligosiloxanes, tissue penetration and long-term stability.

Drug Combinations↗

New substances for intraocular tamponades: perfluorocarbon liquids, hydrofluorocarbon liquids and hydrofluorocarbon-oligomers in vitreoretinal surgery.

UNLABELLED: Perfluorocarbon liquids (PFCLs) and heavy fluorocarbon liquids (HFCLs) are being increasingly used as soft tools during vitreoretinal surgery. However, since long-term intraocular tolerance is still unsatisfactory, at present complete removal at the end of surgery is recommended. With the aim to improve long-term intraocular compatibility and to enlarge the spectrum of clinical applications, modified HFCLs have been developed. HFCL-oligomers with a higher viscosity represent the latest perspective. All three groups of fluorocarbon liquids will be compared with respect to their physical and chemical properties, experimental and clinical results, and prospects for clinical applications. Common features of PFCLs, HFCLs and HFCL-oligomers are biological inertness, specific gravity higher than water, immiscibility with water or blood, and a high gas binding capacity. In PFCLs such as decalin, octane, or phenanthrene. All carbon atoms of the carbon backbone are completely fluorinated. In experimental and clinical use, emulsification, vascular changes and structural alterations of the retina have been described. By only partial replacement of hydrogen atoms by fluorine, the specific gravity of HFCLs is reduced, whereas lipophilic properties increase. Thus HFCLs are potential solvents for intraocular silicone oil remnants. However. after long-term application, side-effects are similar to those observed with PFCLs. Substances of this group, such as F6H6, F6H8, 044, and 062 are used intraoperatively and are currently being investigated for clinical long-term application. With the aim to avoid emulsification and to improve intraocular tolerance, we have developed HFCL-oligomers consisting of 2-4 HFCL molecules with increased viscosity. The oligomers were tolerated well in rabbit eyes for up to 4 months. In contrast to PFCLs or monomers, they did not emulsify nor show vascular alterations. ERGs returned to normal after removal of the oligomer from the eye. Histology of the retina showed mild alterations. CONCLUSION: according to physical properties, experimental intraocular compatibility and stability against emulsification, HFCL-oligomers are promising candidates for improved long-term tamponade of the lower retina. At present, indications for an application in human eyes have to be determined in clinical trials.

Animals↗

Results of vitrectomy and the no-touch-technique using autologous adjuvants in macular hole treatment.

BACKGROUND: Anatomic and functional results of macular holes using vitrectomy and platelet-concentrate (PC) or autologous whole blood (WB) were investigated without peeling any epiretinal membrane in order to minimize retinal trauma. METHODS: 44 patients with macular holes stage II, III and IV underwent a vitrectomy with removal of posterior cortical vitreous (in stage II and III) and C2F6 gas endotamponade. No peeling of any epiretinal membrane or the ILM was performed. In 14 patients autologous WB was injected and in 30 patients autologous PC. The mean follow-up time was 9.3 months. RESULTS: An anatomic closure was observed in 36.4% of patients in the WB-group and in 93.9% of patients in the PC-group. SLO-microperimetry showed a reduction of absolute scotomas in 80% of the WB- and in 75% of the PC-group. In the WB-group 1 retinal detachment and 1 branch vein occlusion occurred; in the PC-group 3 retinal detachments, 1 central artery occlusion, 1 macular pucker, 1 cystoid macular edema, 1 late reopening and 1 secondary glaucoma were observed. In both groups no endophthalmitis occurred. CONCLUSION: If autologous platelet concentrate is available, high anatomic success rates can be achieved without aggressive membrane removal, which may cause retinal damage. Autologous whole blood cannot be recommended as an alternative adjunct for the treatment of macular holes without membrane removal.

Adult↗

Senile schisis detachment with posterior outer layer breaks.

BACKGROUND: Senile retinoschisis with associated retinal detachment in the presence of multiple or large posterior outer layer breaks is rare. Despite many and significant developments in vitreoretinal surgery for this situation, no definitive therapeutic guidelines exist. In an observational study three different approaches performed by two of the authors are presented. METHODS: Eighteen eyes of 18 patients with symptomatic schisis detachment and large posterior outer layer breaks were analyzed retrospectively. The fovea was detached in six eyes. Four eyes had laser photocoagulation and/or transscleral cryopexy (Group I), and five eyes had extensive scleral buckling (Group II). In nine eyes primary vitrectomy and gas endotamponade were performed, including inner layer resection in two eyes (Group III). The median follow-up period was 13 months. RESULTS: Initial anatomic success, which was defined as complete reattachment of the outer retinal layer, was achieved in two of four eyes of Group I, in four of five eyes of Group II, and in seven of nine eyes of Group III. Inner layer separation persisted in 11 of 16 eyes. Visual acuity improved in 3 of 18 eyes, remained unchanged in 9 of 18 eyes, and worsened in 6 of 18 eyes. Complications included in Group I were persistent outer retinal layer detachment (two eyes); in Group II, proliferative vitreoretinopathy (PVR) detachment (one eye), CME (one eye), diplopia (one eye), late redetachment (one eye); in Group III, secondary rhegmatogenous detachment (one eye) PVR detachment (two eyes), macular pucker (one eye), preexisting CME (two eyes), subretinal perfluorocarbon liquid (one eye), transient central serous detachment (one eye), and nuclear sclerosis (five of eight eyes). CONCLUSION: Photocoagulation alone may be considered a first approach in selected cases of schisis detachment complicated by large posterior outer layer breaks. By use of present surgical techniques, today pars plana vitrectomy is the most rational approach allowing an exact evaluation of the complex retinal architecture, a controlled coagulation, and an adequate tamponade of the involved area. Resection of the inner layer seems to increase the risk for epiretinal membrane formation.

Adult↗

[Correlation of morphologic changes between optical coherence tomography and topographic angiography in a case of gyrate atrophy].

PURPOSE: To characterize ultrastrructual changes in atrophic disease of the retina, RPE and choroid as seen with gyrate atrophy using two new diagnostic modalities, optical coherence tomography (OCT) and topographic angiography. PATIENT AND METHOD: OCT images were taken in a patient with pericentral choroidal atrophy using a slit-lamp-adapted OCT system. Ophthalmoscopy, conventional and topographic angiographic findings were correlated to the reflectivity changes as seen on OCT. RESULTS: Areas of chorioretinal atrophy correlated with a loss of reflectivity in the RPE-choriocapillaris complex on OCT. Additionally OCT identified a thinning of the nerve fiber layer. Topographic angiography demonstrated an extensive defect, seen as an area of depression, consistent with a loss of choriocapillaris and larger-sized choroidal vessels. In contrast to conventional angiography, central islands were not found to demonstrate structural intensity, while the midperipheral surrounding area was clearly elevated to physiological levels. CONCLUSION: OCT and topographic angiography provide in vivo insight into morphologic changes within neurosensory retina and choroid caused by pericentral choroidal atrophy.

Choroid↗

Slit-lamp-adapted optical coherence tomography of the anterior segment.

PURPOSE: To evaluate the diagnostic potential of a slit-lamp-adapted optical coherence tomography (OCT) system as an in vivo imaging device for routine clinical examination of the anterior segment of the eye. PATIENTS AND METHODS: In a pilot study, healthy volunteers and patients with different pathologies of the anterior segment were examined with a slit-lamp-adapted OCT system using 100-200 axial scans with 100-Hz line-scan frequency. The scan length is variable up to 7 mm, and the axial depth is 1.5 mm in tissue. RESULTS: The slit-lamp-adapted OCT system allowed direct biomicroscopic imaging of the measured area. Anatomic structures and morphological changes anterior to the attenuating iris pigment epithelium could be visualized with high accuracy. Biometric analyses of the cornea, the chamber angle, the iris and secondary cataract were possible. Complete demonstration of the chamber angle was difficult due to the backscattering properties of the anterior part of the sclera and the consequent shadowing of the most peripheral part of the iris. CONCLUSIONS: Slit-lamp-adapted OCT is a useful diagnostic tool which allows in vivo microscopic cross-sectional imaging of the anterior segment and precise measurement of ocular structures.

Anterior Eye Segment↗