Biomedical subjects

U Eckardt

Publications and source records attributed to U Eckardt.

8 recordsLinked to original sources

PubMed1999

Macular rotation with and without counter-rotation of the globe in patients with age-related macular degeneration.

BACKGROUND: Macular rotation to treat exudative age-related macular degeneration (AMD) involves translocation of the fovea to a site with intact retinal pigment epithelium. To avoid the inevitable postoperative cyclotropia we combined this procedure with torsional muscle surgery. PATIENTS AND METHODS: In 30 eyes the macula was rotated upward by 30-50 degrees following complete artificial retinal detachment and a 360 degrees retinotomy. Simultaneous torsional muscle surgery was not carried out in the first 8 eyes; in the remaining 22 eyes surgery of the oblique muscles was performed alone or in combination with surgery of two or four rectus muscles. Simultaneously or later, muscle surgery was performed on the fellow eye in 17 of these patients. Three of the eight patients who had no primary muscle surgery were operated on later. They had muscle surgery on the macular-rotated eye and on the fellow eye. RESULTS: Postoperatively, the silicone oil was removed from all but one eye and an intraocular lens implanted in all but two eyes. Five eyes developed a postoperative retinal detachment, three of them with proliferative vitreoretinopathy. Three other eyes developed a recurrence of the choroidal neovascularization. At last examination, 18 of the 30 eyes (60%) had a near vision of 0.4 or better, sufficient for the reading of normal newsprint. Six of the eight patients who did not undergo muscle surgery reported considerable disorientation caused by the postoperative diplopia and cyclotropia. The muscle operation, which has been performed in a total of 25 patients, conferred complete freedom from complaints in all but one patient. CONCLUSION: Macular rotation succeeded in restoring reading vision in about half of cases of exudative AMD, at least in the short term. The most serious complication was the development of a retinal detachment. The extremely disorienting side effects of diplopia and tilted image could be prevented or effectively treated by muscle surgery for counter-rotation of the globe, if need be also in the fellow eye.

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PubMed1998

[Orthoptic problems after macular rotation with and without muscle surgery].

BACKGROUND: In spite of new therapeutic approaches the treatment of age related macular degeneration remains unsatisfying. Macular rotation is so far only a rarely employed surgical procedure, where the macula is translocated to an area with intact retinal pigment epithelium. The aim of this study was to elucidate the orthoptic problems of macular rotation and describe possible treatment modalities. PATIENTS AND METHOD: Between February and July of 1997 a macular rotation was performed in 8 patients with exsudative macular degeneration, followed by silicone oil removal and implantation of an intraocular lens. In 3 out of 8 patients the oblique muscles were transposed at the beginning of the surgery to produce an excylotropia. In all patients visual acuity for distance and near was determined pre- and postoperatively along with a complete orthoptic status including measuring of cyclotropia. Mean postoperative follow-up was 5.5 months. RESULTS: Due to the unilateral ectopia of the macula all patients presented with a postoperative strabismus with vertical deviation of 2 degrees to 10 degrees. The change of the visual axis resulted in a displacement of the pupillary reflex. The patients described a cyclotropia of 12 degrees to 45 degrees corresponding to the ophthalmoscopically estimated angle of retinal rotation. Patients after surgery of the oblique muscles showed less cyclotropia with an angle of 12 degrees to 20 degrees. They were less disturbed by diplopia and tilted visual impression than those without muscle surgery. All patients exhibited an abnormal head position with chin up and tilt to the side of the operated eye. CONCLUSION: Macular rotation always causes diplopia because of the unilateral ectopia with cyclotropia and vertical deviation. These problems can be considerably reduced by combining macular rotation surgery with oblique muscles surgery. It may well be that in the future these problems can be completely resolved by additional surgery on the rectus muscles.

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PubMed1997

[Obtaining donor corneas without eyeball removal].

The goal of the present study was to compare the quality of 7-mm corneal buttons taken directly from donor eyes with commonly obtained transplants. Seven-mm porcine corneal specimens and 16-mm cornoscleral specimens were immersed for 3 and 7 days in Optisol culture medium. After 3 days, ultrasonic pachometry revealed a decline to 73% of the original thickness in the 7-mm and to 83% in the 16-mm specimens. After 8 days, the thickness in both groups had returned to 91% of the original values. Light microscopy revealed a homogeneous endothelial layer in both groups. Staining with 0.25% Trypan blue revealed only a few dead cells. The 7-mm specimens exhibited fewer wrinkles in Descemet's membrane than the 16-mm specimens. Scanning electron microscopy of human 7-mm corneal specimens, some obtained directly from donor eyes and stored in Optisol and some trephined from 16-mm corneoscleral specimens after immersion, detected uniformly smooth cutting edges in both groups. Even the endothelia displayed no marked differences. Our results show that the quality of donor specimens removed at the desired size in situ and stored in Optisol equals that of commonly obtained specimens. Further investigations must show the feasibility of this procedure in practice.

Animals↗

PubMed1997

[Removal of the internal limiting membrane in macular holes. Clinical and morphological findings].

UNLABELLED: The recommended treatment for full-thickness macular holes is removal of the posterior hyaloid and sometimes the epiretinal membrane from the retina during vitrectomy in order to release the assumed intravitreous traction. We have employed a technique involving the additional removal of the membrana limitans interna (MLI) from the retina in the vicinity of the macular hole. We report on our clinical results and ultrastructural findings. MATERIALS AND METHODS: Between December 1995 and July 1996, we performed vitrectomies on 39 eyes of 37 patients with full-thickness macular hole. After removal of the attached posterior hyaloid, a specially developed forceps was used to remove a circular area of the MLI approximately three to four disc diameters in size. At the conclusion of the operation, 20% C3F8 gas was injected and the patient instructed to stay in a prone position for 8 days. RESULTS: Intraoperatively, "rhexis" of the MLI only rarely produced bleeding or recognizable retinal edema. Complete closure of the hole was observed postoperatively in 36 of the 39 eyes (92%). A visual improvement of at least two lines was achieved in 77% of eyes with successful closure. Pigment irregularities or edematous changes could not be detected either clinically or by fluorescein angiography in any of the 39 eyes. Electron microscopy was performed on 23 of the membranes. The salient feature was the MLI. Canals leading from the inner to the outer surface of the MLI contained Müller cell processes with clear signs of necrosis or degeneration. On the vitreous side, the MLI usually exhibited myofibroblasts. CONCLUSIONS: The MLI was successfully removed in all 39 eyes with a full-thickness macular hole. This procedure led to very good anatomic and functional results. It remains for future studies to determine the pathogenic significance of the necrotic processes detected by electron microscopy in the MLI canals.

Adult↗

PubMed1996

[Incidence of posterior vitreous detachment in eyes with and without age-related macular degeneration. An ultrasonic study].

Data in the literature differ widely regarding the incidence and age at which posterior vitreous detachment occurs. We investigated the incidence of posterior vitreous detachment in elderly patients and whether this varied between eyes with and without age-related macular degeneration (AMD). Patients ranged in age from 51 to 89 years (median: with AMD 74 years, without AMD 70 years). A total of 251 eyes were examined by B-mode ultrasonography for the presence of posterior vitreous detachment. In 119 eyes no pathological changes were found in the macular region. The other 132 eyes exhibited either exudative or non-exudative age-related macular degeneration. Ultrasonography revealed complete posterior vitreous detachment in only 19% of eyes without and 15% of eyes with macular degeneration. Eyes with macular degeneration, though, had a significantly higher (p = 0.0059) incidence of incomplete vitreous detachment than eyes without macular degeneration. Whether this represents a cause or a consequence of the macular degeneration remains unclear. Our results show that complete posterior vitreous detachment is rarer in the elderly than hitherto assumed.

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PubMed1995

[Effect of traumatic iris defects on spatial perception].

Perforating injury to the eye often results in iris defects in addition to loss of the lens. To determine whether iris defects can impair stereopsis, we tested the stereoscopic vision of 23 patients treated at the University Eye Clinic in Kiel for perforating eye injuries involving the iris and, in most cases, the lens. The patients were divided into three groups according to the severity of the iris defect and the status of the intraocular lens. Individuals with strabismus or visual acuity < 0.5 (20/40) were excluded. Stereopsis was measured using conventional stereopsis tests (Titmus contour stereopsis, Lang global stereopsis) and by means of the Pulfrich pendulum phenomenon. Patients with traumatic aphakia without an iris defect (n = 33) served as controls. Optical rehabilitation was achieved in the controls lenses (n = 16) or intraocular lens implant (n = 17). In group I (intact lens, iris defect < 135 degrees), two of five patients had attained global stereopsis. In group II (implanted or contact lens, iris defect < 135 degrees), only one of the nine patients exhibited global stereopsis. In group III (no lens, iris defect > 135 degrees), none of the nine patients achieved global stereopsis. In the control group, by contrast, more than half of the patients with an implant (10 of 17) and 3 of 16 patients with a contact lens attained global stereopsis. The results indicate that severe iris defects are especially likely to impair stereoscopic vision, more so than traumatic loss of lens alone without an accompanying iris defect.

Adolescent↗

PubMed1995

[Binocular vision in idiopathic macular foramen. Pre- and postoperative findings].

In recent years idiopathic macular hole has become an increasingly frequent indication for vitrectomy. To our knowledge, the literature contains no studies comparing binocular vision before and after vitrectomy. We therefore carried out a prospective study not only on visual acuity following vitrectomy but also, for the first time, on binocular vision. Stereopsis and fusion were evaluated in 37 patients with idiopathic macular holes (stage I-IV) using Bagolini striated glasses, the Titmus stereotest (contour stereopsis), the random dot test (global stereopsis), the Worth four-dot test and the phase-difference haploscope. The tests were performed preoperatively and 10-12 weeks after vitrectomy. Two patients with stage I macular hole showed no loss of stereopsis in conventional tests. One patient, however, exhibited suppression tendencies with partial exclusion. The 18 patients with stage II macular hole had a relative good visual acuity of 0.2-0.6, but subnormal binocular vision with marked suppression of foveal images. Postoperatively, the majority of these patients had symptom-free binocular vision and good stereopsis. Some, however, continued to experience foveal exclusion. Patients with macular hole stage III and IV (n = 17) had the poorest results. Although the postoperative visual acuity improved by 2 to 3 points in some patients (n = 6), in approximately one third it remained limited to global peripheral binocular vision. In summary, our findings show that even in early stages (I and II), macular hole can cause not only reduced visual acuity but also impairment or, in stage II, even loss of binocular vision. Vitrectomy in these early stages often leads to an overall improvement in visual acuity and binocular vision, whereas in more advanced stages vitrectomy often does not affect visual acuity and binocular vision. This should be taken into account when weighing up the indications for surgery.

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PubMedDate not supplied

Keratoprosthesis as an aid to learning surgical techniques on cadaver eyes.

Practice on cadaver eyes can be an essential aid for residents and inexperienced surgeons in learning operative techniques. Cadaver eyes, however, have been of only limited utility for teaching highly complicated procedures because of the obscuring of intraocular structures caused by the rapid post mortem onset of corneal swelling. We have overcome this problem by the use of a silicone keratoprosthesis that provides an excellent view of all intraocular tissues. Our model allows the use of donor eyes unsuitable for transplantation and facilitates the learning of even complicated cataract surgery, and vitrectomy techniques on the human eye. It thus can reduce the rate of complications in operations on patients.

Cadaver↗