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Biomedical subjects

E Reichel

Publications and source records attributed to E Reichel.

At least 37 records · Page 2Linked to original sources
PubMed1995

Optical coherence tomography of central serous chorioretinopathy.

PURPOSE: To assess the potential of a new imaging technique, optical coherence tomography, for the diagnosis and monitoring of central serous chorioretinopathy. Optical coherence tomography is a novel noninvasive, noncontact imaging modality that produces high longitudinal resolution, cross-sectional tomographs of ocular tissue. METHODS: Optical coherence tomography is analogous to ultrasound, except that it uses light rather than sound to obtain higher image resolution in the retina. Cross-sectional tomographs of optical reflectivity within the retina are produced with longitudinal resolution of 10 microns. Optical coherence tomography was used to examine 16 patients at a referral eye center whose initial examination disclosed the clinical diagnosis of central serous chorioretinopathy. The optical coherence tomography results were correlated with slit-lamp biomicroscopy, fundus photography, and fluorescein angiography. RESULTS: The cross-sectional view produced by optical coherence tomography was effective in objectively quantifying the amount of serous retinal detachment in the disease. Optical coherence tomography disclosed detachments that were undetected by slit-lamp biomicroscopy. Longitudinal measurements with optical coherence tomography were successfully able to track the resolution of subretinal fluid accumulation. CONCLUSION: Optical coherence tomography is potentially useful as a new, noninvasive diagnostic technique for quantitative examination of patients with central serous chorioretinopathy and objectively monitoring the clinical course of the serous retinal detachment in this disease.

Adult↗
PubMed1995

Indocyanine green angiography and choroidal neovascularization obscured by hemorrhage.

BACKGROUND AND OBJECTIVE: To determine the use of indocyanine green (ICG) angiography in detecting choroidal neovascularization obscured by hemorrhage. STUDY/DESIGN: Indocyanine green angiography was performed on 20 consecutive patients who were suspected to have choroidal neovascular membranes (CNVs) that were obscured by subretinal or intraretinal hemorrhage on fluorescein angiography. The etiology of choroidal neovascularization was age-related macular degeneration. RESULTS: In all patients, ICG angiography was able to detect some choroidal neovascularization. The entire extent of the CNV was identified in 12 (60%) of these patients after ICG angiography was performed. In the remaining eight eyes (40%), the CNV still was obscured partially by a thick layer of hemorrhage. Difficulty in detection was due to thick subretinal hemorrhage, lipid exudate, and pigment. CONCLUSION: The authors conclude that ICG angiography is superior to fluorescein angiography in showing the presence and extent of CNVs associated with age-related macular degeneration that are almost entirely obscured by hemorrhage.

Choroid↗
PubMed1995

Optical coherence tomography of macular holes.

PURPOSE: To assess the potential of a new diagnostic technique called optical coherence tomography (OCT) for diagnosing and monitoring macular holes. This technique is a novel noninvasive, noncontact imaging modality that produces high longitudinal resolution (10-micron) cross-sectional tomographs of ocular tissue. METHODS: Optical coherence tomography is analogous to ultrasound except that optical rather than acoustic reflectivity is measured. Cross-sectional tomographs of the retina profiling optical reflectivity in a thin, optical slice of tissue are obtained with a longitudinal resolution of 10 microns. Optical coherence tomography was used to examine 49 patients with the clinical diagnosis of idiopathic full-thickness macular hole, impending macular hole, epimacular membrane with macular pseudohole, or partial-thickness hole. The resulting OCTs were correlated with contact lens and slit-lamp biomicroscopy, fundus photography, and fluorescein angiography. RESULTS: The cross-sectional view produced by OCT was effective in distinguishing full-thickness macular holes from partial-thickness holes, macular pseudoholes, and cysts. Optical coherence tomography was successful in staging macular holes and provided a quantitative measure of hole diameter and the amount of surrounding macular edema. Optical coherence tomography also was used to evaluate the vitreoretinal interface in patients' fellow eyes and was able to detect small separations of the posterior hyaloid from the retina. CONCLUSION: Optical coherence tomography appears potentially useful as a new, noninvasive, diagnostic technique for visualizing and quantitatively characterizing macular holes and assessing fellow eyes of patients with a macular hole. The tomographic information provided by OCT eventually may lead to a better understanding of the pathogenesis of macular hole formation.

Adult↗
PubMed1995

The digital indocyanine green videoangiography characteristics of well-defined choroidal neovascularization.

PURPOSE: To evaluate the digital indocyanine green (ICG) videoangiography characteristics of well-defined choroidal neovascularization (CNV). METHODS: The authors retrospectively reviewed all ICG angiograms performed at the New England Eye Center over a 2-year period. Included in this study were all patients with the clinical and fluorescein angiographic diagnosis of well-defined CNV according to the Macular Photocoagulation Study Group criteria. RESULTS: Of the 25 eligible patients, 18 (72%) had a well-demarcated area of ICG hyperfluorescence that was observed either both early and late (6 patients = 24%) or only late (12 patients = 48%) on the ICG angiogram. Five patients (20%) showed only poorly demarcated late hyperfluorescence on ICG angiography. Two patients (8%) had type II occult CNV associated with classic CNV as per the Macular Photocoagulation Study Group criteria. Both patients showed a late, well-demarcated area of ICG hyperfluorescence greater than the area imaged with fluorescein angiography. CONCLUSIONS: Choroidal neovascularization which is well-defined on fluorescein angiography has variable ICG appearances. When there is late leakage associated with a well-defined CNV on fluorescein angiography (type II occult CNV), ICG angiography may more completely delineate the extent of the lesion.

Aged↗
PubMed1995

Imaging of macular diseases with optical coherence tomography.

BACKGROUND/PURPOSE: To assess the potential of a new diagnostic technique called optical coherence tomography for imaging macular disease. Optical coherence tomography is a novel noninvasive, noncontact imaging modality which produces high depth resolution (10 microns) cross-sectional tomographs of ocular tissue. It is analogous to ultrasound, except that optical rather than acoustic reflectivity is measured. METHODS: Optical coherence tomography images of the macula were obtained in 51 eyes of 44 patients with selected macular diseases. Imaging is performed in a manner compatible with slit-lamp indirect biomicroscopy so that high-resolution optical tomography may be accomplished simultaneously with normal ophthalmic examination. The time-of-flight delay of light backscattered from different layers in the retina is determined using low-coherence interferometry. Cross-sectional tomographs of the retina profiling optical reflectivity versus distance into the tissue are obtained in 2.5 seconds and with a longitudinal resolution of 10 microns. RESULTS: Correlation of fundus examination and fluorescein angiography with optical coherence tomography tomographs was demonstrated in 12 eyes with the following pathologies: full- and partial-thickness macular hole, epiretinal membrane, macular edema, intraretinal exudate, idiopathic central serous chorioretinopathy, and detachments of the pigment epithelium and neurosensory retina. CONCLUSION: Optical coherence tomography is potentially a powerful tool for detecting and monitoring a variety of macular diseases, including macular edema, macular holes, and detachments of the neurosensory retina and pigment epithelium.

Adult↗
PubMed1995

Vitreoretinal emergencies.

Emergencies that affect the visual system can be devastating, with loss of vision being the most feared complication. In addition, visual signs and symptoms may indicate the coexistence of systemic conditions that can result in stroke, myocardial infarction and death. In patients who present with sudden loss of central or peripheral vision or pain in or around the eye, a careful examination of the eye and adnexa is warranted. Traumatic injuries also necessitate a careful examination to locate treatable problems. Prompt evaluation and treatment of vitreoretinal emergencies are important in the preservation of vision. These conditions can result in loss of vision or other severe consequences, especially if they are not promptly evaluated and treated by an ophthalmologist specializing in vitreoretinal disorders.

Emergencies↗
PubMed1994

Diabetic vitrectomy.

Proliferative diabetic retinopathy is one of the leading causes of permanent vision loss. Vitrectomy for the complications of proliferative changes has resulted in preservation of vision. Recent studies have focused on the cellular and structural changes in patients with proliferative changes. Data obtained from the early Treatment of Diabetic Retinopathy Study show that the rate of vitrectomy is reduced in eyes that have early-scatter photocoagulation in comparison with those that have deferral of treatment. The efficacy and complications of silicone oil tamponade have been more carefully evaluated with respect to complex detachments associated with proliferative diabetic retinopathy.

Diabetic Retinopathy↗
PubMed1994

Indocyanine green dye-enhanced diode laser photocoagulation of poorly defined subfoveal choroidal neovascularization.

Indocyanine green (ICG) is a dye with an absorption peak (795 to 810 nm) similar to the emission peak of the diode laser (805 nm). Therefore, ICG dye-enhanced diode laser photocoagulation may permit the selective ablation of ICG-retaining choroidal neovascular membranes (CNVM) with relative sparing of the neighboring neurosensory retina. Ten patients with poorly defined subfoveal CNVM were treated with ICG dye-enhanced diode laser photocoagulation and followed for an average of 15 months. One of the 10 patients experienced an immediate significant drop in visual acuity after photocoagulation. Obliteration of the CNVM at the site of laser photocoagulation was confirmed by fluorescein angiography and ICG angiography. Subfoveal chorioretinal scar formation was noted postoperatively in all 10 patients. At last follow up, 9 of these 10 patients had no more than a two-line increase or decrease in visual acuity. These preliminary results suggest that poorly defined subfoveal CNVM can be successfully treated by ICG dye-enhanced diode laser photocoagulation with minimal adverse affect on visual acuity in most cases.

Aged↗
PubMed1992

A special irrigation liquid to increase the reliability of laser-induced shockwave lithotripsy.

For the laser-induced shockwave lithotripsy (LISL) the laser-pulses of a Q-switched Nd:YAG laser produce an optical breakdown in the irrigation liquid surrounding the urinary stone. Subsequently high-pressure shockwaves are emitted causing stone fragmentation. Since the LISL is an endoscopic technique, problems arise from the transmission of the laser pulses through optical fibers. The intensity threshold for an optical breakdown in commonly used saline solution amounts to 21 GW/cm2, in optical silica fibers, to about 3 GW/cm2. Therefore bare fibers cannot be used without being destroyed by a breakdown. So we have developed an irrigation liquid by adding small quantities of metal ions to saline solution to lower the threshold intensity. The most suitable ion was Fe3+ in a concentration of 0.02 mmol/l, which shows a lowering to 5 GW/cm2. In combination with a spherically shaped fiber exit the intensities that have to be transmitted are below the threshold of the fiber material. Using this irrigation liquid the overall reliability of the method could be significantly increased and several stone fragmentations can be performed with a single optical fiber.

Evaluation Studies as Topic↗
PubMed1992

Oxycephaly, bilateral ectopia lentis, and retinal detachment.

We report the case of a man with oxycephaly, bilateral ectopia lentis, and total retinal detachment in one eye. Although the association of retinal detachment with ectopia lentis is well known, this is the first report to our knowledge of a craniosynostosis, specifically oxycephaly, being associated with ectopia lentis and retinal detachment.

Adult↗
PubMed1990

Mutations within the rhodopsin gene in patients with autosomal dominant retinitis pigmentosa.

BACKGROUND: Night blindness is an early symptom of retinitis pigmentosa. The rod photoreceptors are responsible for night vision and use rhodopsin as the photosensitive pigment. METHODS AND RESULTS: We found three mutations in the human rhodopsin gene; each occurred exclusively in the affected members of some families with autosomal dominant retinitis pigmentosa. Two mutations were C-to-T transitions involving separate nucleotides of codon 347; the third was a C-to-G transversion in codon 58. Each mutation corresponded to a change in one amino acid residue in the rhodopsin molecule. None of these mutations were found in 106 unrelated normal subjects who served as controls. When the incidence of these three mutations was added to that of a previously reported mutation involving codon 23, 27 of 150 unrelated patients with autosomal dominant retinitis pigmentosa (18 percent) were found to carry one of these four defects in the rhodopsin gene. All 27 patients had abnormal rod function on monitoring of their electroretinograms. It appears that patients with the mutation involving codon 23 probably descend from a single ancestor. CONCLUSIONS: In some patients with autosomal dominant retinitis pigmentosa, the disease is caused by one of a variety of mutations of the rhodopsin gene.

Base Sequence↗
PubMed1990

A point mutation of the rhodopsin gene in one form of retinitis pigmentosa.

The gene for autosomal dominant retinitis pigmentosa in a large pedigree of Irish origin has recently been found to be linked to an anonymous polymorphic sequence, D3S47 (C17), from the long arm of chromosome 3. As the gene coding for rhodopsin is also assigned to the long arm of chromosome 3 and is expressed in rod photoreceptors that are affected early in this blinding disease, we searched for a mutation of the rhodopsin gene in patients with autosomal dominant retinitis pigmentosa. We found a C----A transversion in codon 23 (corresponding to a proline----histidine substitution) in 17 of 148 unrelated patients and not in any of 102 unaffected individuals. This result, coupled with the fact that the proline normally present at position 23 is highly conserved among the opsins and related G-protein receptors, indicates that this mutation could be the cause of one form of autosomal dominant retinitis pigmentosa.

Adult↗
PubMed1990

Laser-induced shock wave lithotripsy. Influence of laser pulse energy and irrigation solutions on stone disintegration.

With a high intensity Q-switched Nd-YAG laser shock waves can be generated in a liquid close to the calculus. Up to 80 mJ single pulse energy with 8 nsec pulse duration can be transmitted through flexible quartz fibers. Energy conversion and enhancement can be accomplished at the fiber tip with optical focussing of the light at the quartz tip, with irrigation solutions and with high pulse energies. Iron-III-dextran solutions (1 mg Fe3+/1) and magnesium chloride (50 mmol/l) increased the pressure in the laser induced breakdown up to ten times (8,000-10,000 bar). Smaller stone particles and higher efficacy in stone fragmentation could be achieved.

Humans↗
PubMed1990

[Laser lithotripsy with the neodymium YAG laser].

Laser-induced shock wave lithotripsy (LISL) with a Q-switched neodymium-YAG laser depends on the generation of a laser-induced breakdown in the fluid surrounding the stone. An oscillating plasma bubble is created, directing shock waves towards the stone. These cavitational effects fragment the calculus into small particles. A new bifunctional laser is introduced: this allows both nanosecond pulses for shock wave generation and disintegration of urinary calculi and millisecond pulses for biliary stones and tissue coagulation. It can be supplied with 320-, 400-, and 600-micron fibers. We have treated 189 ureteric stones in 185 patients with laser lithotripsy utilizing flexible ureteroscopes (n = 26) or rigid ureteroscopes (n = 159). It proved possible to fragment 179 stones into small pieces. In eight patients LISL was not successful. A rigid cystoscope that can be dismantled into an upper and lower hemisheath for the introduction of flexible endoscopes into the ureter without prior dilatation of the ureteral orifice was used in 15 patients.

Cystoscopes↗