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Biomedical subjects

Arnd Gandorfer

Publications and source records attributed to Arnd Gandorfer.

At least 37 records · Page 2Linked to original sources
PubMed2004

[Presumed ocular histoplasmosis syndrome (POHS) in a non-endemic area].

BACKGROUND: POHS is a chorioretinal disease rarely occurring in non-endemic areas. METHODS: We present the case of a 35-year old male patient with symptoms of dry eyes, but subjectively no other ocular complaints. However, visual acuity of the right eye was 20/20, but only 20/200 in the left eye. RESULTS: On fundoscopic examination both eyes showed alterations consistent with all four typical features of presumed ocular histoplasmosis syndrome. In both eyes in the mid-periphery punched-out chorioretinal spots were found, an extensive peripapillary atrophy and peripheral linear chorioretinal streaks were seen. Moreover, in the left eye an atrophic macular scar existed, presumably due to subretinal neovascularisation. The macula of the right eye was normal, serology testing for Histoplasma capsulatum negative. CONCLUSIONS: As the patient had never travelled to endemic areas such as the USA but exhibited all features of POHS, the case shows that POHS may also occur in European, non-endemic areas. This further supports the theory that other factors play a role in the etiopathology of this syndrome.

Adult↗
PubMed2004

Trypan blue in macular pucker surgery: an evaluation of histology and functional outcome.

PURPOSE: To evaluate possible adverse effects of trypan blue on the ultrastructure of the human retina, to report on functional outcome of macular pucker surgery with and without the use of trypan blue, and to evaluate the ultrastructure of tissue harvested during surgery. DESIGN: Experimental study and prospective matched-pair analysis of two consecutive, interventional case series. METHODS: Possible adverse effects on the ultrastructure of the human retina by trypan blue were evaluated in three donor eyes in an experimental study using trypan blue in concentrations of 0.02%, 0.15%, and 0.25%. The retinas were histologically evaluated. In the clinical study, the functional outcome (visual acuity, Goldmann perimetry) of 10 eyes of 10 consecutive patients with intraoperative use of trypan blue (0.15%) was analyzed (group 1) and compared with the functional outcome in a matched group of patients (preoperative visual acuity, pre- and postoperative lens status) who had undergone vitrectomy without trypan blue assistance (group 2). Only patients with an idiopathic macular pucker were included. Epiretinal tissue of all eyes was harvested and prepared for ultrastructural analysis using light and electron microscopy. RESULTS: In the postmortem study, no significant alterations of the inner retina suggesting adverse effects of trypan blue concentrations of 0.02% were observed. In contrast, a disorganization of the innermost retina and an absence of the internal limiting membrane (ILM) was seen after the application of undiluted 0.15% and 0.25% trypan blue. In the clinical study, the median best-corrected visual acuity was 20/50 in both groups (range, 20/200-20/40) before surgery. Mean age was 70 years in group 1 (with trypan blue) and 69 years in group 2 (without trypan blue). Mean follow-up time was 4 months in group 1 and 5.6 months in group 2. Postoperatively, median visual acuity had increased to 20/32 (range, 20/100-20/25; Wilcoxon test P = 0.01) in group 1 and to 20/40 (range, 20/100-20/25; P = 0.09) in group 2. The difference between the two groups was not statistically significant (P = 0.4). Four of 10 patients without and 7 of 10 patients with trypan blue staining experienced an improvement of visual acuity (gain of 2 lines or more). No postoperative visual field defects were noted in either group. Histologic analysis of tissue harvested intraoperatively revealed the regular picture of undisturbed fibrocellular membranes. In some specimens, a layer of interspersed collagen was noted between epiretinal cells and the ILM, suggesting two different morphologic types of macular pucker. In a few sections, areas of cellular elements were detected adjacent to the retinal surface of the ILM. CONCLUSION: Trypan blue in a concentration of 0.02% is not associated with morphologic alterations of the inner retinal layers in our postmortem study. After application of 0.15% and 0.25% trypan blue solutions, a disorganization of the inner retinal layers was observed; the ILM was absent. We did not find any adverse effects of an intraocular trypan blue concentration of 0.02% on functional status. Our study further indicates that the functional results of surgery with and without the use of trypan blue are comparable. As the question of toxicity of a dye can not be answered by morphological observations alone, further experimental studies will be needed.

Adult↗
PubMed2004

Posterior vitreous detachment induced by microplasmin.

PURPOSE: To demonstrate the efficacy of microplasmin in inducing posterior vitreous detachment (PVD) and to evaluate the human and the feline retina after treatment. METHODS: Thirteen human donor eyes were injected with 62.5, 125, or 188 micro g microplasmin. The 13 fellow eyes received balanced salt solution. Four of the microplasmin-treated eyes received an additional intravitreal gas injection. After incubation at 37 degrees C for 30 minutes, all globes were placed in 4% paraformaldehyde. Retinal specimens were processed for scanning (SEM) and transmission (TEM) electron microscopy. Five feline eyes were injected with 14.5- or 25- micro g microplasmin. Animals were killed after 1 day, 3 days, or 3 weeks, and retinal specimens were evaluated by electron and confocal microscopy. RESULTS: In all control eyes, SEM demonstrated the cortical vitreous covering the inner limiting membrane (ILM). Intravitreal injection of 125 or 188 micro g microplasmin resulted in complete PVD. After treatment with 62.5 micro g microplasmin, SEM revealed collagen fibrils covering the ILM. Additional gas injection did not change the dose necessary for PVD. In vivo in cats, 25 micro g microplasmin resulted in complete PVD after 3 days. After 3 weeks, there was complete PVD with both doses of microplasmin. The retina and the ILM were well preserved in all eyes. CONCLUSIONS: Both after death and in vivo, microplasmin induces a dose-dependent cleavage between the vitreous cortex and the ILM without morphologic alterations of the retina. In the feline eye, there is no cellular response of retinal glial cells or neurons.

Adult↗
PubMed2003

The effect of indocyanine-green on functional outcome of macular pucker surgery.

PURPOSE: To compare functional results after surgery for macular pucker either with or without indocyanine-green staining of the internal limiting membrane (ILM) and to evaluate the ultrastructure of the tissue removed. DESIGN: Retrospective analysis of two successive, consecutive, interventional case series. METHODS: Functional outcome (visual acuity, Goldmann perimetry) of 48 eyes of 48 consecutive patients with (group 1, n = 20) or without (group 2, n = 28) intraoperative use of indocyanine-green (ICG) was retrospectively analyzed. For statistical analysis, best-corrected visual acuity measured at the last presentation was considered. Only patients with an idiopathic macular pucker were included. Surgery consisted of three-port pars plana vitrectomy, and removal of epiretinal tissue and the ILM in a second step. Commercially available ICG with a concentration of.05% and an osmolarity of 275 mOsm was used to stain the ILM. The surgical technique used for both groups was identical, except the use of ICG. Epiretinal tissue of all eyes was harvested and prepared for ultrastructural analysis using light and electron microscopy. RESULTS: Follow-up time was 8.5 months in group 1 and 5.4 months in group 2. Whereas patients operated on without ICG experienced a significant improvement of median best-corrected visual acuity from 20/63 (range, 20/400 to 20/32) preoperatively to 20/40 (range, 20/200 to 20/25) postoperatively (P < .001), median best-corrected visual acuity remained 20/63 before (range, 20/200 to 20/63) and after (range, 20/400 to 20/20) (P > .9) ICG-assisted peeling. There was a statistically significant difference (P = .013) in best-corrected postoperative visual acuity of patients with and without the use of ICG. An improvement of vision was noted in 86% of patients without and 55% of patients with ICG-assisted surgery. Thirty-five percent of patients after ICG application presented with a deterioration of visual acuity. Furthermore, we observed large visual field defects in 7 of 20 patients after ILM staining. No visual field defects were noted after conventional peeling. Histologic analysis revealed clear differences between the two groups concerning the amount of cellular elements adjacent to the retinal surface of the ILM: There was more cellular debris visible in specimens after ICG application during surgery. Additionally, in contrast to surgery without ILM staining, epiretinal cells had ruptured and lost their cellular integrity after ICG-assisted vitrectomy. CONCLUSIONS: Indocyanine green-assisted surgery for macular pucker might have an adverse effect on functional outcome. Although there were obvious differences in the ultrastructure of tissue removed during surgery, our observations cannot be explained by histologic analysis alone. Other, so far unknown mechanisms of action must be considered.

Adult↗
PubMed2003

Indocyanine green for successful repair of a long-standing macular hole.

PURPOSE: To report on the successful closure of a persistent chronic macular hole using indocyanine green (ICG) during the second surgical approach. DESIGN: Interventional case report. METHODS: A patient with a long standing macular hole (18 years) underwent pars plana vitrectomy with peeling of the internal limiting membrane (ILM). While no dye was used during the first operation, ICG (0.05%, Pulsion) was applied during the second procedure. The light source was turned off immediately after the ICG application until the dye was washed out after a period of 15 seconds. Tissue harvested during the second surgical approach was prepared for electron microscopy. RESULTS: After the failure of the first operation, areas of incomplete ILM peeling could be stained using ICG and a thorough ILM removal was achieved. Postoperatively, the macular hole was closed, as confirmed by optical coherence tomography. Visual acuity increased from 20/200 to 20/50. No visual field defects were seen postoperatively. There were only few cellular elements adherent to the retinal surface of the ILM as seen during electron microscopy. CONCLUSION: In cases where tractional forces due to incomplete ILM removal are considered responsible for the persistence of a macular hole, ICG is useful to identify areas of unpeeled ILM. Under certain safety precautions no adverse effect on functional outcome was seen.

Aged↗
PubMed2003

Retinal damage from indocyanine green in experimental macular surgery.

PURPOSE: Previous work has shown that indocyanine green (ICG)-assisted peeling of the inner limiting membrane (ILM) may cause retinal damage. In this study, a toxic and a photodynamic effect of ICG at the vitreoretinal interface was assumed. METHODS: Ten human donor eyes were hemisected, and 0.05 mL of 0.05% ICG was poured over the trephined macula in eight eyes. After 1 minute, the dye was drained by irrigation. The macula in each of two eyes was illuminated for 3 minutes with wavelengths of 380 to 760, 380 to 620, or 620 to 760 nm. Two eyes were treated with ICG only, and two eyes were illuminated only. Retinal specimens from the macula and the untreated retina were processed for light and electron microscopy. The irradiance of the light source and the absorption properties of ICG were measured. RESULTS: Exposure of the ICG-stained ILM to wavelengths beyond 620 nm resulted in severe damage to the inner retina, including loss of ILM, cellular disorganization, and fragmentation of the cytoplasm. ICG staining alone or in combination with wavelengths of 380 to 620 nm disclosed rupture of Müller cells with detachment of the ILM, but no other cellular disorganization. Eyes subjected to illumination only showed no abnormalities. CONCLUSIONS: The spectral absorption properties of ICG may account for a possible photodynamic effect of ICG at the vitreoretinal interface. ICG alone induces ILM detachment and disruption of Müller cells even without intentional peeling of the membrane. It is assumed that accumulation of the dye at the vitreomacular interface may enhance the concentration and osmolarity of ICG at the retina beyond intravitreous values and critical limits.

Adolescent↗
PubMed2003

Light-absorbing properties and osmolarity of indocyanine-green depending on concentration and solvent medium.

PURPOSE: To evaluate the absorption spectrum and osmolarity of three currently used indocyanine green (ICG) products at different concentrations and with different solvent media. METHODS: The absorption spectrum and osmolarity of three different ICG products (Pulsion, Munich, Germany; Akorn, Buffalo Grove, IL; and Laboratoires SERB, Paris, France) were analyzed. Each ICG was further diluted with balanced salt solution or glucose 5%. Four different concentrations were evaluated: 0.005%, 0.0025%, 0.001%, and 0.00025%. ICG (Pulsion) diluted in viscoelastic material (Healon; Pharmacia, Stockholm, Sweden) was analyzed at a concentration of 0.0025%. The following parameters were measured: absorption spectrum between 400 and 1000 nm, osmolarity, and the emission spectrum of the light source of a commonly used vitrectomy machine (Megatron; Geuder, Heidelberg, Germany). RESULTS: Independent from the manufacturer, concentrations of 0.005%, 0.0025%, and 0.001% ICG diluted in balanced salt solutions (BSS and BSS Plus; Alcon Pharmaceuticals, Fort Worth, TX) and glucose 5% showed two maxima, one at approximately 700 nm and a second one at 780 nm. There was an increase from zero to maximum absorption between 600 and 700 nm and a return to zero between 800 and 900 nm. The absorption band of ICG diluted in the viscoelastic material was similar to the saline solution (BSS or BSS Plus)-diluted ICG. At lower concentrations of 0.001% or 0.00025%, the peak at 700 nm decreased, forming a shoulder in the curve, whereas the peak at 780 nm remained stable. Osmolarity was in the range of 302 to 313 mOsM for BSS Plus-diluted ICG. When glucose 5% was used for ICG dilution, absorption between 600 and 700 nm decreased, and osmolarity was lower (between 292 and 298 mOsM). The light source emission was between 380 and 760 nm. CONCLUSIONS: Dilution of ICG using the balanced salt solutions BSS or BSS Plus resulted in a steep increase of absorption starting at 600 nm. In clinical practice, there is an overlap between the absorption band of ICG and the emission curve of the light source, resulting in a possible photosensitizing effect, especially at higher ICG concentrations. This effect becomes less likely with decreasing ICG concentrations or when glucose 5% is used as a solvent medium.

Absorption↗
PubMed2002

Vitreoretinal morphology of plasmin-treated human eyes.

PURPOSE: To investigate the ultrastructure of the vitreoretinal interface following an intravitreal injection of plasmin. METHODS: Plasmin (2 U/0.1 ml) was injected into the vitreous cavity of five postmortem human eyes. The five fellow eyes received phosphate-buffered saline and served as controls. After incubation at 37 degrees C for 30 minutes, the globes were placed in fixative and hemisected. Specimens for scanning and transmission electron microscopy were obtained using a corneal trephine. RESULTS: All plasmin-treated eyes showed complete vitreoretinal separation with sparse collagen fibrils covering the inner limiting membrane. All control eyes showed an attached cortical vitreous. At the vitreous base, there was no cleaving effect. The retinal morphology of plasmin-treated eyes was unchanged. CONCLUSIONS: Plasmin induces a cleavage between the vitreous cortex and the inner limiting membrane without morphologic alteration of the retina.

Aged↗
PubMed2002

Scanning laser ophthalmoscope findings in acute macular neuroretinopathy.

PURPOSE: The typical reddish-brown retinal lesions of acute macular neuroretinopathy are difficult to detect. We demonstrate a role for scanning laser ophthalmoscopy in the diagnosis of acute macular neuroretinopathy. METHODS: Observational case report. We used scanning laser ophthalmoscopy in a 23-year-old woman with acute macular neuroretinopathy. RESULTS: In contrast to biomicroscopy, color fundus photography, and red-free fundus photography, scanning laser ophthalmoscopy precisely disclosed the size of the lesions within the macula. Microperimetry showed absolute scotomata corresponding to the macular lesions. CONCLUSION: Scanning laser ophthalmoscopy enhances the visibility of the retinal lesions in acute macular neuroretinopathy. The lesion size can be determined more precisely, and follow-up of patients is more accurate compared with conventional techniques.

Acute Disease↗
PubMed2002

Long-term follow-up after macular hole surgery with internal limiting membrane peeling.

PURPOSE: To report long-term anatomical and functional results after pars plana vitrectomy with peeling of the internal limiting membrane (ILM) for idiopathic macular hole. DESIGN: Prospective, nonrandomized, consecutive series. METHODS: Ninety-nine patients with a follow-up of at least 12 months were included. The surgical technique consisted of a standard pars plana vitrectomy, removal of the ILM, and an intraocular gas tamponade (15% hexafluoroethane [C(2)F(6)] gas mixture) followed by head-down positioning for at least 5 days. Follow-up examinations included a clinical examination, Goldmann perimetry, optical coherence tomography, and static microperimetry using a Rodenstock scanning laser ophthalmoscope (SLO-105). Stimulus size was 0.2 degrees (Goldmann II), intensities employed were 0 and 12 dB. Twenty-degree fields were used for all tests. RESULTS: Mean period of review was 32 months (median 34). Anatomic closure was achieved in 86 (87%) of 99 patients by one surgical procedure. Nine patients underwent a successful second operation with an improvement of visual acuity in 7 patients. The closure rate after two surgical interventions was 96%. Best-corrected visual acuity improved from a median of 20/100 preoperatively to a median of 20/40 postoperatively (P <.001). An improvement of visual acuity was achieved in 94% of patients. In 13 of 99 patients (13%) a combined vitrectomy and cataract surgery with intraocular lens implant was performed; 72 patients (73%) underwent cataract surgery later. Ninety of 99 patients (91%) were pseudophakic on last presentation. Paracentral scotomata did not change in size, density, or shape over time. Its incidence was not correlated with the stage of the macular hole. No postoperative epiretinal membrane formation or late reopening of the macular hole was observed. One patient presented with a peripheral visual field defect after vitrectomy. CONCLUSIONS: Macular hole surgery with peeling of the ILM without the use of adjuvants or ILM staining leads to good functional long-term results. Paracentral scotomata remained subclinical in most cases and may be due to a mechanical trauma of the nerve fiber layer.

Aged↗
PubMed2002

Indocyanine green-assisted peeling of the internal limiting membrane in macular hole surgery affects visual outcome: a clinicopathologic correlation.

PURPOSE: To report the ultrastructure of the internal limiting membrane (ILM) after macular hole surgery with indocyanine green (ICG) staining and to investigate an association with the postoperative functional outcome. DESIGN: Retrospective, noncomparative analysis of a consecutive case series. METHODS: Twenty eyes of 20 patients after macular hole surgery with ICG staining were included. Visual acuity and Goldmann perimetry were obtained before and after surgery. The ILM was obtained during three-port pars plana vitrectomy for idiopathic macular hole. Twenty-five milligrams of sterile ICG powder was dissolved in 5 ml of sterile water as recommended by the manufacturer and then diluted in balanced salt solution. The ultrastructure of the ILM was analyzed using light and transmission electron microscopy. Osmolarity and pH of the ICG solution were measured preoperatively. RESULTS: There was no statistically significant improvement of postoperative visual acuity after ICG-assisted peeling (P =.755). In seven patients, postoperative visual field defects occurred. Indocyanine green-stained specimens revealed cellular elements resembling the plasma membrane of Müller cells and other undetermined retinal structures adherent to the retinal side of the ILM. Histologic findings disclosed no difference between patients with and without visual field defects after the use of ICG. The osmolarity of the ICG solution applied was 275 mOsm; pH was 7.5. CONCLUSIONS: Intravitreal application of ICG may cause retinal damage by altering the cleavage plane to the innermost retinal layers. That may result in less improvement of visual acuity and unexpected visual field defects. The underlying mechanisms of action remain unclear and are the subject of ongoing investigations.

Aged↗