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Biomedical subjects

E Schütte

Publications and source records attributed to E Schütte.

At least 19 recordsLinked to original sources

[Modified radiation administration in Er:YAG laser ab externo sclerostomy].

BACKGROUND: Ab externo sclerostomy enables the restrained aqueous humour drain via a microgram wide corneoscleral canal into the subconjunctival space being an alternative surgical method in glaucoma therapy. The tissue ablative infrared laser radiation (2.94 microgram) was applied until now via a quartz fiber manually pushed forward in permanent tissue contact. Our aim was the development of a new applicator tip without manual feed in order to achieve a reduction in times for construction and maintenance of the former tip as well as in the risk of an infection and mechanical damage of intraocular structures. MATERIAL AND METHOD: In pig eye experiments, the laser parameters were varied in histological and scanning electron microscopic evaluation (pulse energy: 10-60 mJ, repetition rate: 5-17.5 Hz, combinations of constant power: 200 mW). Their influence on the canal shape and the morphology of the internal ostium has been proven in special tests. RESULTS: The new development of the applicator tip (core diameter: 550 microgram) enables a conical profile of the beam (diameter 500-150 microgram) within a distance of 2-3 mm, now without pushing the fiber forward ("fixed fiber"). Smooth canal surfaces, a small homogeneous necrosis zone (25 microgram) and only few tissue ruptures have been seen histologically and on SEM. The correlations of ablation rates/-speed as well as canal characteristics are more significant to energy densities than to repetition rates. First clinical application was technically successful. CONCLUSIONS: The new applicator tip optimizes the method of Er: YAG-laser ab externo sclerostomy from the technical and surgical point of view.

Animals↗

[Intraocular pressure after extracapsular cataract extraction with posterior chamber lens implantation--sulcus versus capsular bag fixation].

BACKGROUND: In this retrospective study the postoperative alteration of intraocular pressure after cataract extraction and posterior chamber lens implantation was analyzed statistically. The influence on intraocular pressure between different positions of the loops (sulcus versus bag) was compared. PATIENTS AND METHOD: The posterior chamber lens implantation was performed on 267 eyes with 129 sulcus implanted and 138 in-the-bag implanted intraocular lenses. The average age of the patients was 74.8 respectively 71.9 years, with an equal ratio of sex. In surgery the viscoelastic experimentation of the nucleus was done via corneoscleral cut. A x-crossed suture sealed the corneoscleral wound followed by subconjunctival injection of corticosteroids. The postoperative medication for 4-6 weeks consisted of a corticosteroid and antibiotic combination. RESULTS: The average intraocular pressure of the sulcus implanted respectively in the bag implanted intraocular lenses increased from 15.4 mm Hg respectively 15.9 mm Hg preoperatively to 16.3 respectively 15.8 mm Hg at the first postoperative day. After two months the intraocular pressure decreased to 14.6 respectively 14.1 mm Hg. That means a pre- to postoperative difference of -0.8 respectively -1.8 mm Hg. CONCLUSIONS: In summary both groups showed a slight decrease in average intraocular pressure after two months. In comparison to the sulcus implanted intraocular lens the decrease of intraocular pressure was more than 1 mm Hg in case of the in the bag implanted lens. This decrease was statistically significant but may be considered of less clinical interest.

Aged↗

Evaluation of intraocular pressure with Healon and Healon GV in sutureless cataract surgery with foldable lens implantation.

PURPOSE: To evaluate transient increases in intraocular pressure (IOP) after use of high-viscosity viscoelastic agents in cataract surgery. SETTING: Military Hospital, Ulm, Germany. METHODS: In a prospective, randomized study, we evaluated IOP following cataract surgery using two different viscoelastic substances (Healon, Healon GV). The viscosity of Healon GV is 10 times higher than that of Healon because of higher concentration and molecular weight. Patients having identical phacoemulsification procedures (sutureless clear corneal tunnel incision with foldable silicone lens implantation) (N = 60) and identical viscoelastic removal were assigned to groups of 15 based on viscoelastic used and removal time (20 or 40 seconds). Intraocular pressure was measured preoperatively and at 6, 24, 36, and 48 hours and 1 month postoperatively. RESULTS: The highest mean IOP elevations in both viscoelastic groups were obtained at 24 hours postoperatively (2.9 mm Hg +/- 4.3 [SD] with Healon and 3.3 +/- 6.3 mm Hg with Healon GV). There were no statistically significant differences between the two viscoelastics and the two removal times during the entire follow-up period (unpaired t-test), but standard deviations were higher in the Healon GV groups at 6 and 24 hours. Two patients in the Healon groups and three in the Healon GV groups required medical treatment for IOP within the first 24 postoperative hours; however, all five patients had an IOP lower than 22 mm Hg on the second postoperative day. CONCLUSIONS: Based on postoperative IOP, both viscoelastics can be equally well removed from the anterior chamber. Incidence of high IOP using high-viscosity hyaluronic acid is minimized by the described removal technique.

Aged↗

[Ab externo sclerostomy with the Er:YAG laser: report of outcome after 2 years].

OBJECT: Results over a period of 24 months of performing the Er:YAG laser ab externo sclerostomy. MATERIAL AND METHODS: The procedure was performed 81 times (chronic glaucoma with open angle (n = 55) and narrow angle (n = 15), 6 secondary glaucoma, 4 pigment glaucoma, 1 normal pressure glaucoma) in 74 eyes of 64 patients at the age of 70 +/- 10 years without any peribulbar anesthesia. The pulse energy was 11 mJ with a repetition rate of 7 Hz. Antimetabolites were not applicated. Success was defined as an IOP of less than 22 mm Hg or a decrease of at least 30%, with or without anti-glaucoma medication. RESULTS: The mean IOP of all cases decreased from preoperatively 28 +/- 8.1 mm Hg (Success group: 26.7 +/- 7.3 mm Hg) to 15 +/- 8.4 mm Hg (Success group: 14.6 +/- 7.8 mm Hg) on the first postoperative day. The success rate was about 50% within the period of two weeks to six months and decreased to about 15% in the 24th month. Complications were iris incarceration/synechia (n = 33), hypotony (n = 36) with consequent choroidal detachment (n = 8), hyphema (n = 19) and more pronounced inflammation symptoms (n = 10). In most cases, the early postoperative outflow failure is caused by iris incarceration into the internal ostium. The scarring tendency of the episcleral tissue leads to closure of the external ostium after months. Resurgery was necessary in 26 cases. CONCLUSIONS: Further efforts should be directed to maintain the intact corneoscleral morphology of the canal, created by an optimized method of the surgical technique. The application of antimetabolites in correct dosage or the implantation of modified silicon draining systems would be helpful.

Aged↗

[Postoperative intraocular pressure in the first days after intraocular administration of hyaluronic acid solution with different viscosities].

BACKGROUND: Viscoelastic substances are used in anterior segment surgery to reduce tissue trauma and endothelial cell loss and to serve as space maintainer. Healon GV (approximately greater viscosity), a hyaluronic acid product with a ten times higher viscosity than Healon, is utilized in complicated procedures (vitreous pressure, flat anterior chamber, congenital cataracts, etc.) and often in phacoemulsification. Intraocular pressure (IOP) rise following incomplete removal is a known problem. MATERIALS AND METHODS: A prospective randomized study was performed to evaluate the IOP following cataract surgery with Healon or Healon GV and different removal times (RT). Forty patients (forty eyes) having uncomplicated phacoemulsification with foldable silicone posterior chamber lens implantation and identical viscoelastic removal technique were assigned to four groups: Healon with 20 or 40 seconds (sec.) RT, Healon GV with 20 or 40 sec. RT. All surgeries were performed by the same surgeon using the same technique especially for the removal of the viscoelastic. All patients had an identical pre- and postoperative medication. Intraocular pressures were obtained using Goldman's applanation tonometry preoperatively, six, 24, 36, and 48 hours postoperatively. RESULTS: The IOP follow-up showed no significant difference between the two viscoelastic substances and the two different removal times of 20 and 40 sec. (t-test). In four patients (two of the Healon-groups, two of the Healon GV-groups) the IOP required treatment. On the second postoperative day, the same four patients showed IOP lower than 22 mm Hg. The highest mean-IOP (mm Hg) in both Healon-groups was obtained at 24 hours postoperatively: 18.5 +/- 3.9 SD (Healon); 17.3 +/- 5.9 SD (Healon GV). CONCLUSION: The incidence of postoperative rise in IOP using high viscosity hyaluronic acid (Healon GV) can be minimized by the applied removal technique. Both viscoelastics-despite of higher molecular weight and viscosity-can be removed equally from the anterior chamber following phacoemulsification and posterior chamber lens implantation utilizing IOP as a parameter in vivo.

Aged↗

[Congenital familial cornea plana with ptosis, peripheral sclerocornea and conjunctival xerosis].

BACKGROUND: Cornea plana is an extremely rare, congenital hereditary malformation of the corneo-scleral shape. The curvatures of cornea and sclera are nearly equal with an indistinct limbus. In addition to the flatness, there is a peripheral sclerocornea that produces a pseudomicrocornea. The low corneal refraction and the short anterior segment often result in hyperopia. Myopia is also described. Usually the posterior segment is not involved. MATERIALS AND METHODS: A young man of 22 years, his three- and five-year-old sons, and his newborn daughter showed this hereditary abnormality of the cornea. In this uncommon anomaly we measured corneal curvature, refraction, diameter and in three of the four patients echographical length of the bulbi. RESULTS: The family showed an autosomal dominant inheritance of the cornea plana. The corneal refraction was less than 32 diopters. The scleral encroachment caused an oval cornea measuring horizontally between 5 and 6.5 mm, vertically 4 to 5 mm. Additionally a pseudoblepharoptosis and a conjunctival xerosis of the father and his sons was observed, which is not regularly found. A-scan measuring of the bulbi revealed age-related normal values. CONCLUSIONS: There is no evidence for progression of this anomaly during life. No therapeutical consequences are necessary. To preserve a satisfactory function a conscientious orthoptical maintainance should be guaranteed.

Adult↗

[Comparative study of ab-externo sclerostomy with the excimer and Er:YAG laser].

The specific ablative effect of pulsed 308 nm XeCl-excimer laser radiation (4 mJ 80 Hz) on the tissue has proved its worth in clinical use in glaucoma patients. However, the cytotoxic and mutagenic photochemical reactions induced by intraocular ultraviolet irradiation could theoretically be cataractogenic and retinotoxic. Unlike the excimer laser technique, ab externo sclerostomy with the Er:YAG laser (2940 nm/11 mJ, 7 Hz) excludes these risks. Histological and scanning electron microscope analysis of pig eyes showed thin, and smoothly limited zones of necrosis and only minimal irritation of the adjacent tissue and a slightly wavy surface. A newly developed handpiece for the Er:YAG laser enables energy transport via zirconium fluoride fiber and coupling to a quartz fiber tip with a core diameter of 320 microns. Er:YAG laser sclerostomy has so far been performed on 16 eyes in which the average preoperative IOP was 29 mmHg. The procedure took only a few minutes and the patients reported feeling no pain although retrobulbar anesthesia was not induced. The postoperative average IOP was less than 20 mmHg after 6 weeks and for the rest of a maximum observation period of 12 weeks. Reoperation was necessary in 2 cases. Er:YAG laser ab externo sclerostomy could be another alternative for the operative therapy of glaucoma.

Aged↗

[Excimer laser sclerostomy of secondary glaucoma].

Initial results after nine ab externo sclerotomies on seven patients awaiting enucleation because of intensive pain caused by secondary glaucoma have encouraged us to present the methods used for this technique of fistula construction and the course in these patients. A special applicator permits precise manual positioning of the excimer laser beam (lambda = 308 nm) subconjunctivally at the limbus using a quartz-quartz fiber (diameter: 0.32 mm). The energy applied at the fibertip is 4 mJ per pulse, with a repetition rate of 80 Hz. All patients undergoing the operation, which lasted only a few minutes, were treated as out-patients without a retrobulbar anaesthesia. Because of the minimal irritation of the anterior chamber, only antibiotic treatment was required after the operation. The intraocular pressure immediately decreased to normal levels after the operation without any further glaucoma treatment in five cases. In the other two cases reduced, but still minimally elevated, pressure was recorded. In the case of one heavily inflamed eye, which had been subjected to two operations, pain felt by the patient was relieved when the pressure was reduced. The maximum period of post-operative follow-up so far is over 10 months and the decrease of intraocular pressure has remained adequate without any additional antiglaucoma therapy. In all cases enucleation was avoided.

Glaucoma↗

[Aphakic retinal detachment in myopic eyes].

The incidence of retinal detachment following cataract extraction was studied in a myopic population of 803 eyes, which were selected by a measurement of the axial length out of 3,184 cases consecutively operated on. The incidence of retinal detachment following intracapsular cataract extraction was 1.5%, which was very similar to that after extracapsular cataract extraction: 1.8%, in the lowest range of date published in the literature. The incidence of retinal detachment of the pseudophakic myopic eye (operated on with the extracapsular technique, combined with implantation of a posterior chamber lens, the PMMA optic disc, diameter 5.8 mm with a 10 degrees angulated haptic and modified prolene-C loops) was 1.1%, in which the cases of intraoperative posterior capsule rupture with vitreous loss were included. There was no correlation between the incidence of retinal detachment and axial length. All cases of retinal detachment appeared in eyes with an axial length of 24.2 to 27.0 mm. In 9 of 11 (75%), retinal detachments occurred during the first 18 months after cataract extraction. In our opinion extracapsular cataract extraction with implantation of a posterior chamber lens is the best method of providing postoperative retinal detachment of the cataractous myopic eye. The question of the incidence of retinal detachment following cataract removal by the extracapsular technique and secondary capsulotomy by the Nd-YAG laser is still interesting.

Cataract Extraction↗

[Vitreoretinal dirofilariasis].

The present paper reports on a 41-year-old patient who complained of moving shadows and impaired vision after vacations in southern Europe and central Africa. On ophthalmoscopic examination the cause was found to be an extremely agile worm, whitish, as thin as an end-artery, and approx. 6 mm long, in front of the macula and later in the vitreous. Following treatment with Hetrazan (diethylcarbamazine) and Mintizol (thiabendazole) the worm could no longer be detected. On the basis of morphologic and chemical studies normal helminth worms were ruled out, as were human filariae. It may be assumed with reasonable confidence that the worm observed was an animal parasite of the genus Dirofilaria.

Adult↗

[Flattening of the anterior chamber and myopic results in sulcus fixation of posterior chamber lenses].

Ultrasonographic biometry was performed in 56 patients immediately after implantation of a posterior chamber intraocular lens to measure the position of the lens. A modified applanation method was used to avoid injury to the scleral suture. Ten months later, 44 of these patients were examined by the same method. The anterior chamber depth was found to have decreased from 4.26 mm (s = 0.39 mm) in the immediate postoperative period to 4.2 mm ten months later. However, axial length, at 23.28 mm postoperatively and 23.34 mm at follow-up, and mean corneal refraction (43.28 D and 43.34 D, respectively) were practically unchanged. There was a shift in the spheric equivalent of refraction from postoperative emmetropia (mean -0.07 D) to slight myopia (mean -0.76 D) at follow-up. This mean myopization of 0.69 D corresponded to the tendency toward a shallower anterior chamber. Shrinkage and fibrosis of the posterior capsule, reduced elasticity of the polypropylene loops, flattening of the cornea and axial changes are discussed as possible causes. The tendency toward myopization should be taken into account when calculating the power of sulcus-fixated posterior chamber lenses.

Anterior Chamber↗

[Comparison of the Kolling distance vision stereo-test with current stereo-test procedures].

A new type of stereotest for distant vision (after Kolling) is compared with established stereotests for distant (different types of Zeiss Polatest) and near vision (Titmus, TNO, Lang tests) in a total of 203 patients. The Kolling test is based on the three-rod method in accordance with Helmholtz. The apparatus does not require separation of the visual input of the two eyes. This new stereotest is practice-oriented, quick, easy to understand and gives reliable and reproducible results. The test cannot be completed successfully with monocular viewing, if the head is fixed. The results show a good correspondence between the Kolling test and the Zeiss Polatest using disparate outlined figures. The Zeiss Polatest using random-dot patterns turned out to have the strictest criteria for this purpose of all stereotests. Interestingly enough, subjects performed much better in stereotests for near vision (Titmus, TNO tests) than in those for distant vision (Kolling test, different types of Zeiss Polatest). The widespread use of stereotests of near vision in driving tests is therefore problematic.

Adolescent↗

Combined cataract-glaucoma operation and its complications with the 7-S-intraocular lens.

The new generation of intraocular lenses placed in the sulcus or in the bag allows implantation even in glaucoma patients under certain conditions. Patients with intraocular pressure between 25 and 30 mm Hg underwent Argon laser trabeculoplasty before implantation. In patients with regulated intraocular pressure between 15 and 20 mm Hg not even an iridectomy was performed implanting the 7-S posterior chamber lens. An average degree of the intraocular pressure of 1.5 mm Hg was found after 6 months. Preoperative endothelial cell counting facilitates the indication for implanting an intraocular lens.

Atrophy↗

[Case report of a choroidal osteoma].

Choroidal osteoma caused blurred vision in a 45-year-old man. Ophthalmoscopy showed a characteristic tumor with irregular elevation and of a yellowish color with a vascular network on the surface. Ultrasonic A-scan findings, hyperfluorescence in angiograms and visibility on computer tomograms confirmed the diagnosis, even though the patient's age and sex, and the location of the tumor, were unusual.

Choroid Neoplasms↗

[Reversible star formation of the macula in retinal angiomatosis].

Case report concerning a young man in whom exudative retinitis had occurred as a result of the A-V shunt of a retinal angioma, leading to sudden loss of vision. With argon laser and xenon arc photocoagulation a minor hemorrhage cleared up spontaneously, the retina remained attached and vision increased to 20/25 within 1 year. The authors believe that the combined photocoagulation insured an interruption of blood flow in feeder vessels and the breakdown of the intervening capillary bed.

Adult↗