Search PubMed⌕ Search

Biomedical subjects

C Eckardt

Publications and source records attributed to C Eckardt.

At least 37 records · Page 2Linked to original sources

[Clinical and histologic findings after several weeks of intraocular tamponade with perfluorodecalin].

Perfluorocarbon residues sometimes remain in the eye following vitreoretinal procedures employing liquid perfluorocarbons. According to the literature, one or two droplets do not appear to damage the ocular tissue. The question of whether this also applies to larger volumes was investigated in two eyes of two patients. Both eyes were injected with perfluorodecalin for removal of luxated lens in two patients. In one patient approximately 3 ml perfluorodecalin remained in the eye for 3 months postoperatively, in the other patient approximately 4 ml for 4 months. The eye of the first patient developed an inoperable complicated retinal detachment. The second eye developed a secondary glaucoma requiring additional cyclocryocoagulation after removal of the perfluorocarbon. Histological examination of excised retinal tissue revealed extensive destruction of the normal architecture with a marked reduction in the number of cells in the nuclear layers. It remains unclear whether these findings can be attributed to toxic or mechanical damage.

Aged↗

The occurrence of macrophages in the retina and periretinal tissues in ocular diseases.

Specimens obtained from eyes with various ocular diseases were examined immunohistochemically using a panel of monoclonal antibodies (Ki-M1P, K1-M4, CD68, anti-lysozyme, and anti-cytokeratins) to establish the occurrence of macrophages in the retina and periretinal tissues and to determine whether they can be distinguished from migrated cells of the retinal pigment epithelium (RPE). Eyes with proliferative diseases and intraocular melanomas were found to contain more macrophages in the retina than those with uveitis and glaucoma. The epiretinal membranes and subretinal space in eyes of the former group often exhibited additional clustered macrophages and migrated RPE cells. In all specimens studied, RPE cells reacted with antibodies KL-1, CK7, CK18, or CK19 but not with the CD68, Ki-M1P, or lysozyme antibodies. Control eyes without any known disease also contained rare macrophages in the retina. In conclusion, macrophages are regular and normal constituents of the retina that can be clearly distinguished immunohistochemically from migrated RPE cells. Their frequency varies depending on the type of ocular disease involved.

Antibodies, Monoclonal↗

[Ocular tissue after intravitreous silicone oil injection. Histologic and electron microscopy studies].

The intraocular tolerance of silicone oil is still a matter of ongoing controversy. To evaluate a possible migration of silicone oil into eye tissues we examined various tissues from eyes that were injected with silicone oil for a period of 6 months to 3.5 years. The histological and ultrastructural characteristics of these tissues are reported (cornea, 4 cases; iris, 3 cases; retina, 8 cases; retinal pigment epithelium and optic nerve, 1 case). In the iris and in corneas showing a perforating injury light microscopy revealed vacuoles presumably lying in the cytoplasm of macrophages. Using immunohistochemistry and electron microscopy, macrophages could also be found in the retina of eyes that had been filled with silicone oil for longer than 6 months. Using energy dispersive X-ray analysis, vacuoles could be identified as storage sites of the silicone oil. This observation demonstrates that a long-term silicone oil tamponade may cause a migration of silicone oil into the retina and other ocular tissues. In order to prevent this complication, removal of silicone oil should be performed as early as possible.

Choroid↗

Vitrectomy in multifocal chorioretinitis.

In nine patients suffering from multifocal chorioretinitis with panuveitis, we obtained no impressive therapeutic benefit from vitrectomy. Seven women and two men ranging in age from 63 to 86 years underwent pars plana vitrectomy at 3-28 months after the first signs of uveitis had appeared. Previous medical treatment had always been unsuccessful. Vitrectomy was performed in one eye of eight patients and in both eyes of one patient. In addition, in two patients a cataract was removed by phacoemulsification and an intraocular lens was implanted. A visual improvement of one or two lines was achieved postoperatively in most cases, but the visual acuity decreased to preoperative values or less within 6 months. The surgical treatment showed no obvious effect on the intensity or frequency of uveitis relapse. In all cases, vitrectomy specimens were serologically negative for herpes-group viruses. Histologically, no malignancy was detectable. Immunohistochemistry studies revealed that a large number of the vitreous cells bore T-lymphocyte markers (mostly CD2-, CD3-, and CD4-positive); about one-third of the vitreous cells were macrophages, and B-lymphocytes were only rarely detected. In conclusion, pars plana vitrectomy in multifocal chorioretinitis achieved no positive long-term result. There was no diagnostic hint as to whether the cause of the uveitis might have been of a viral, malignant, or autoimmune origin. Therefore, multifocal chorioretinitis remains poorly understood in terms of its etiology and adequate treatment.

Aged↗

Identification of silicone oil in the retina after intravitreal injection.

Retinal tissue obtained from 2 eyes that had been injected with silicone oil for 2 years was stained with monoclonal antibodies against macrophages and studied by light and electron microscopy and energy-dispersive x-ray analysis. Both specimens showed areas with a relatively intact architecture as well as parts with loss of normal structure. In both areas, immunostaining showed single intraretinal macrophages. Energy-dispersive x-ray results clearly demonstrated that some of the intracellular and extracellular vacuoles within the retina represented the storage sites of silicone.

Adult↗

Results of silicone oil removal from eyes treated with retinectomies.

We reviewed the results of silicone oil removal from 32 eyes that had been treated with peripheral retinectomies during vitrectomy for retinal detachment with proliferative vitreoretinopathy. With a minimum follow-up of 6 months, 3 developed a retinal detachment after silicone oil removal. Twenty-eight eyes attained a final visual acuity of 0.1 or better and 15 eyes attained 0.2 or better. Only in 3 eyes was visual acuity decreased after silicone oil removal, whereas 20 eyes showed an improvement in vision. One eye was hypotonous and 11 eyes required antiglaucomatous agents at the last examination. Final visual acuity as well as final intraocular pressure did not correlate with either the retinectomy size or with the duration of the silicone oil tamponade.

Adolescent↗

Biocompatibility of silicone oil and high-density liquids. An immunologic study.

Silicone oil and high-density liquids can be useful tools in the treatment of complicated retinal detachments. To test whether these substances induce specific and/or unspecific inflammatory responses, we performed immunoassays on 60 rats of two different inbred strains. After sensitization, each rat was injected in the right foot pad with either silicone oil, fluorosilicone oil, perfluorooctane, or perfluoropolyether. Depending on the inbred strain, the volume of the foot pads increased up to the fifth day, indicating an injection-induced inflammatory reaction. Histopathological examination of rats injected with silicone oil showed infiltration by mononuclear cells and occasional giant cells. In rats receiving fluorosilicone oil, additional eosinophilic reactions were observed. The most pronounced reactions occurred after injection of the two perfluorocarbons, which induced a greater number of giant cells and a slight granulomatous reaction. The degree of tissue response was independent of the type of sensitization; the majority of the draining popliteal lymph nodes showed no enlargement. Our findings demonstrate that all substances tested induced inflammatory though unspecific responses.

Animals↗

[Treatment of complicated retinal detachment. Intraoperative use of perfluorodecalin].

Perfluorodecalin was injected into the vitreous cavity of 36 eyes during vitreous surgery for complicated retinal detachment. This low-viscosity liquid is immiscible with water, chemically inert and has a high specific gravity. In all cases the posterior retina was flattened without the need for a posterior retinotomy for drainage of subretinal fluid. Injection of the fluid caused stabilization of the retina and improved removal of peripheral epiretinal membranes. In 1 case a retinal break occurred during injection of the liquid and perfluorodecalin entered the subretinal space. In 4 eyes a small mobile droplet of residual perfluorodecalin was observed post-operatively. During follow-up periods of up to 11 months no retinal changes caused by the residual liquid were observed.

Fluorocarbons↗

[A convex-concave contact lens for vitreoretinal operations with the BIOM].

A new convex-concave contact lens for wide-angle vitreoretinal surgery with the BIOM was developed. Placed on an eye, in which silicone oil is injected, it prevents the formation of an optically disturbing oil-water-film on the surface of the cornea. Thus the new contact lens leads to an essential improvement of the fundus view intraoperatively without affecting the optical properties of the BIOM.

Contact Lenses↗

[Venous vascular anomalies within the myelinated retinal nerve fiber area].

We report the case of a 25 year old caucasian female who was presented to our clinic with a four year history of recurrent vitreous hemorrhages, myelinated retinal nerve fibers and ipsilateral anisometropic myopia, astigmatism and amblyopia of her right eye. On fluorescein angiography small, postcapillary venous malformations in the area of myelinization were diagnosed. Vascular anomalies within regions of myelinated retinal nerve fibers have not been described so far. Even if actual leakage itself from the anomalous vessels could not be documented, vitreous hemorrhaging did not recur after successful lasercoagulation and obliteration of the vascular anomalies.

Adult↗

[Immunohistochemical findings of epiretinal membranes after silicone oil injection].

During vitreoretinal surgery, 23 epiretinal membranes from eyes treated with silicone oil were removed. They were examined by immunohistochemical methods and compared with 15 membranes from eyes affected by proliferative vitreoretinopathy (PVR) and not treated with silicone oil and with 4 membranes from eyes with intermediate uveitis. PVR membranes from eyes treated with silicone oil showed a high level of macrophages and a strong expression of HLA-DR. Additionally, lymphocytes were found in PVR membranes, a finding that has not been described before. Similar changes were seen in proliferations removed from eyes affected by uveitis, but these membranes were found to have smaller amounts of extracellular substance. In contrast to this, most cells in the PVR membranes from eyes not treated with silicone oil react with vimentin, GFAP and cytokeratin. In none of these membranes were we able to find T-lymphocytes. It is not possible to say whether or not the different findings are attributable ot the silicone oil.

Extracellular Matrix↗

[Visual changes after silicone oil injection].

Patients frequently complain of visual changes after intraocular silicone oil injection. The degree of these changes as well as refractive changes were analyzed in 11 aphacic eyes that had a postoperative visual acuity of at least 0.1. Visual acuity and refraction were obtained with the patients in a supine position. Then multiple visual acuity tests were done and refraktion was measured up to 12 times a day with the patient sitting erect. All tests were done with a constant pupillary diameter. Mean differences of 3 D between the objective and subjective refraction were noted. In most eyes there was a shift of spherical equivalents towards hypermetropia after a change in posture from supine to erect. The mean shift was 3.4 D (range 0.75-6.25 D). Seven out of 11 patients showed an increase in visual acuity of up to 4 optotypelines within the first 4 h after changing to an erect position. Total eye examination and testing of best-corrected visual acuity were performed again between 4 weeks and 15 months after silicone oil removal (mean 9.6 months). On examination, all eyes had a totally attached retina; none developed secondary glaucoma. Ten out of 11 eyes did not attain a final visual acuity that was better than the best corrected visual acuity before silicone oil removal.

Diabetic Retinopathy↗

[Bacteriocidal effect of preoperative use of gentamicin in comparison with PVP-iodine solution].

This clinical study was designed to evaluate the difference between preoperative treatment of the conjunctiva with either gentamicin eyedrops or a half-strength povidone iodine solution. We treated 50 eyes of 50 patients who came for cataract surgery and showed bacterial growth in the first conjunctival smear with gentamicin eyedrops at 1-h intervals for at least 10 h. The second smear was taken the next day. At the same time, half strength povidone-iodine solution on was applied to the follow-eye. After 2 min the second smear was taken. With both methods a significant reduction of bacterial growth was achieved. The average number of colonies decreased from 1620 to 63 after treatment with gentamicin and from 1338 to 214 after treatment with povidone iodine. There was no significant difference between the two methods. No allergic reactions or corneal haze after application of povidone iodine were observed.

Cataract Extraction↗

Experimental intraocular tolerance to liquid perfluorooctane and perfluoropolyether.

Three kinds of perfluorinated liquids (a perfluorooctane and two perfluoropolyethers) were evaluated as vitreous replacements. Tolerance to these liquids in rabbit eyes was investigated for periods of up to 2 months. Clinically, droplet formation of the liquids occurred within a few days of intravitreal injection. Histologic examination revealed no pathologic retinal changes 8 hours after surgery. At 6 days after surgery, hypertrophy of the Müller cells with bumplike protrusions into the interphotoreceptor space could be observed. At 1 month after surgery, light and electron microscopic examination showed larger droplike protrusions of Müller cells related to localized foldings of the outer retinal layers and rarefication of photoreceptor nuclei and loss of outer segments. Frequently disarranged, granule-loaded macrophages appeared in these areas. At 2 months after surgery, vesicles with low electron density appeared in some areas at the border between receptors and retinal pigment epithelium. In other areas pigment epithelial cells showed distinct hypertrophy (with drusen) toward the droplike Müller cell protrusion, together with narrowing of the interreceptor space. These findings were almost totally confined to the lower part of the retina that had been in permanent contact with the liquids. No histologic differences were noted between perfluorooctane- and perfluoropolyether-injected eyes. The results suggest that the liquids are not candidates for long-term vitreous replacement, but may be suitable for short-term intraoperative use.

Animals↗

[Postoperative necrotizing sclerokeratitis].

Two cases of necrotizing sclerokeratitis following uncomplicated extracapsular cataract extraction are reported. Enucleation became necessary in the first case despite initially successful immunosuppressive treatment. In the second case, a stable condition was achieved by covering the affected area with a patch of lyophilized dura. Two years later, however, phthisis bulbi developed.

Aged↗

Intraocular tolerance to silicone oils of different specific gravities. An experimental study.

Different methylphenylsilicone (MPS) and fluorosilicone (FS) oils having a higher specific gravity than water were investigated as vitreous replacements. Their intraocular tolerance in vitrectomized aphakic rabbit eyes was evaluated for periods of up to 4 months and compared to that of regular polydimethylsilicone oil (PDMS). Weakly fluorinated FS and weakly phenylated MPS showed a presumably toxic effect on the retina. As compared to highly fluorinated FS, highly phenylated MPS showed better intraocular tolerance; however, inflammatory reaction was slightly more extensive than in eyes filled with PDMS.

Animals↗