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Biomedical subjects

P Kroll

Publications and source records attributed to P Kroll.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Simultaneous bilateral rhegmatogenous retinal detachment].

BACKGROUND: Rhegmatogenous retinal detachment (RD) has a strong bilateral tendency. It results from a chronic degenerative process, wherein both eyes are involved. However, simultaneous RD of both eyes is a rare finding. In a retrospective study we investigated the clinical course as well as risk factors in this kind of manifestation. METHODS: From 1989 to 1994, 931 patients underwent operation because of RD in our ophthalmologic department. Eleven of these patients presented a simultaneous bilateral RD exceeding one hour. We excluded patients with consecutive retinal detachments and retinal detachments deriving from intraocular surgery, trauma, tractive hole formation or heredodegeneration. RESULTS: Seven out of 11 patients with simultaneous bilateral retinal detachment were under 35 years of age. All of these presented multiple round holes (3-19). Horse-shoe tears were causative in 6 eyes; these patients all were over 50 years of age. There was a preponderance of males (73%) in our study. Nine patients were myopic with diopters ranging from -0.5 to -11.25. Retinal reattachment by a single intervention was achieved in 21 eyes, whereas 3 eyes had to undergo a second operation for a redetachment. CONCLUSION: Simultaneous bilateral RD, the most severe type of a retinal resp. vitreoretinal degenerative process, occurs predominantly in patients under the age of 35 with multiple bilateral round holes. We therefore conclude that multiple round holes in this group of patients are not to be regarded as a benign form of degeneration.

Adolescent↗
PubMed1995

[Phototherapeutic keratectomy in recurrences of granular corneal dystrophy after keratoplasty].

BACKGROUND: Recurrences of granular corneal dystrophy (Groenouw type I dystrophy) after penetrating keratoplasty have been often reported in the literature. Up to now the therapy of these recurrences consists in performing a lamellar or penetrating re-keratoplasty. As those recurrent opacities at first are located in the area of Bowman's membrane and the superficial corneal stroma, a phototherapeutic keratectomy (PTK) with an excimer laser offers a therapeutic alternative to re-keratoplasty. PATIENTS AND METHODS: We describe three eyes of two patients with recurrent opacities on the transplant after successful keratoplasty because of granular corneal dystrophy. In all eyes we performed an excimer-laser PTK (Keratom of Schwind Company, Kleinostheim/Germany, wave length 193 nm) after abrasion of the epithelium with a hockey-knife. The depth of ablation depended on the location of the opacities and was between 7 microns and 35 microns. During the excimer-laser treatment several biomicroscopical slit-lamp controls were performed to make sure whether a sufficient depth of ablation was obtained. RESULTS: The opacities could be totally removed in all eyes by excimer-laser PTK. Postoperatively the visual acuity increased and the patient's photophobia decreased. At the same time a slight progression of hyperopia developed depending on the depth of ablation. During the follow-up period of 5 to 12 months no recurrent opacities could be found until now. CONCLUSIONS: Phototherapeutic keratectomy with the excimer laser seems to be a good alternative to re-keratoplasty in superficially located recurrences of granular corneal dystrophy in a graft after keratoplasty. A slight progression of hyperopia depending on the depth of ablation has to be accepted. The future will show whether there will develops recurrent opacities of the dystrophy after an excimer laser treatment.

Aged↗
PubMed1995

[Early vitrectomy in endogenous juvenile uveitis intermedia--a long-term study].

BACKGROUND: The intermediate uveitis is one of the most common intraocular manifestations of inflammation during infancy and adolescence. The success of intensive pharmacological treatment is rather limited and often associated with heavy side effects. PATIENTS AND METHODS: In 25 eyes with juvenile uveitis intermedia (age of the patients between 5 and 18 years, mean 13.5 years) and visual acuities between 0.02 and 0.4 (mean 0.19) an early vitrectomy was performed after failure of conservative treatment and peripheral cryocoagulation. RESULTS: Almost all patients (22 out of 25) showed an improvement of visual acuity within the first 6 months of the surgery. Among the patients with a remarkable improvement of visual acuity 7 eyes had a chronic cystoid macular oedema which showed a regression postoperatively. Additionally, the number and the course of inflammatory periods could be reduced postoperatively. An increase of preexisting lens opacities, however, has not been noticed even after a follow-up period of 10 years. CONCLUSIONS: The results show that an early vitrectomy in cases of juvenile uveitis intermedia often leads to a stabilization or an improvement of visual acuity and a regression of the inflammatory attacks (episodes). Therefore, in children and adolescents with endogenous uveitis intermedia a pars plana vitrectomy instead of a long-term systemic immunosuppression associated with heavy side-effects should be considered.

Adolescent↗
PubMed1995

[Keratomileusis in situ in high grade myopia. Initial results].

Besides photorefractive keratectomy (PRK) with the excimer laser, different methods of intrastromal keratectomy are now available for refractive corneal surgery in myopic patients. The first results of keratomileusis in situ in high-grade myopia are presented. Keratomileusis in situ was performed with a semiautomatic mechanical microkeratome in 15 amblyopic eyes with a refraction (spherical equivalent) between -12 and -25 D (mean -18.18 D). The principle of the method consists in a change of the anterior corneal curvature by resection of a refractive lenticulus out of the corneal stroma. The first step is the removal of a superficial corneal lamella consisting of epithelium, Bowman's layer, and superficial stroma. After this, the refractive lenticulus is resected out of the stroma, and the superficial lamella is sutured back to the cornea. The postoperative refraction (spherical equivalent) 4 weeks after the operation ranged between + 1.5 and -4.5 D (mean -1.37 D). Best corrected preoperative visual acuity was achieved again postoperatively within 4 weeks in most of the patients; in some patients the postoperative visual acuity even exceeded the preoperative values. After an uncomplicated healing process in 14 of the 15 eyes the cornea remained completely transparent in the optical zone, and the effect of treatment remained stable. Scar formation was observed in one eye only, where the lamellar cut was inadvertently performed in Bowman's layer and not in the stroma. Thus, keratomileusis in situ is a supplementary technique to conventional refractive surgery in high-grade myopia. Its advantages are quick optical rehabilitation and an almost scar-free optical zone, because the integrity of Bowman's layer is almost completely maintained with this technique.

Adolescent↗
PubMed1995

[Traction vitreoretinal opticopathy in proliferative diabetic vitreoretinopathy].

UNLABELLED: In patients with proliferative diabetic vitreoretinopathy the authors noticed tractive vitreoretinal distortion of the optic disk to the nasal side. As a result of this distortion a reduction in visual acuity, pallor of the optic disk, and changes in the visual evoked potentials were registered. The disease in called "tractive vitreoretinal opticopathy." METHOD: We examined 15 diabetics with vitreoretinal traction and temporal pallor of the optic disk, as well as a reduction in visual acuity. Six patients were observed retrospectively and 9 patients prospectively before and after vitrectomy. Pre- and postoperative examinations included visual acuity, visual field, fluorescence angiography, and the conduction of visual evoked potentials (VEP). RESULTS: Within a postoperative follow-up of 2-8 months (mean 6.5 months) a return of optical vitality combined with an increase in visual acuity could be seen in 14 of 15 patients. In addition, some of the patients showed an improvement in the amplitudes and a reduction in the latency of the VEP. CONCLUSIONS: The authors assume that the axoplasmatic flow in the optic nerve fibers is reduced according to vitreoretinal traction. Furthermore, the traction may cause elongation of the capillaries, resulting in reduced perfusion of the optic disk. For these reasons early vitrectomy in patients with tractive vitreoretinal opticopathy is recommended.

Adult↗
PubMed1995

Tissue plasminogen activator as a biochemical adjuvant in vitrectomy for proliferative diabetic vitreoretinopathy.

Tissue plasminogen activator (TPA) converts plasminogen to plasmin, thereby inducing fibrinolysis. In ophthalmologic surgery of subretinal hemorrhages, it is used to dissolve blood clots. As the blood-retina barrier of diabetic patients has broken down, plasminogen can enter the vitreous compartment in these cases. It is known that plasmin dissolves extracellular matrix protein in the vitreous interface. For that reason se used TPA in pars plana vitrectomy (ppV) of proliferative diabetic vitreous retinopathy (PDVR). Ten patients undergoing ppV for PDVR of stage A or B (Kroll classification) were included in a prospective study. At 15 min prior to vitrectomy, 100 microliters balanced salt solution was injected into the vitreous cavity. As randomized, the injection fluid contained either 25 micrograms TPA or only buffer solution. At this stage, the operating surgeon did not know whether TPA was injected or not. The grade of difficulty and complications of the operation were scored and documented. In all cases the operating surgeon correctly classified verum or placebo after surgery. Preparation of vitreous cortex and pathological membranes proved to be less difficult when TPA had been injected. Moreover, no severe bleeding occurred in this group in spite of marked PDVR. We conclude that TPA can be used in ppV without producing severe side effects. Disintegration of the vitreous interface causes a posterior detachment of the vitreous body, thus facilitating ppV.

Adolescent↗
PubMed1995

Panophthalmitis with acute scleral necrosis after brachytherapy of a malignant melanoma of the ciliary body.

A 52-year-old man who presented with a large ciliochoroidal malignant melanoma was treated by application of a 106Ru plaque. At 8 days after removal of the plaque, severe panophthalmitis with rapidly progressive scleral necrosis at the site of the tumor made enucleation inevitable because of impending perforation of the globe. Microscopic examination revealed an intense inflammatory response and almost complete necrosis of the tumor and overlying sclera. Possible mechanisms for the occurrence of this rare complication are discussed.

Acute Disease↗
PubMed1994

[Systematic search of the posterior vitreous cortex during vitrectomy. Technique, complications and results].

We present the results of a prospective study trying to answer the question: when a clinical or echographic premacular vitreous detachment occurs, is it still possible to find a preretinal membrane at the surface of retina? We looked for such a membrane in 50 consecutive vitrectomies for various indications. We found and removed such a membrane in 42 cases but were unable to obtain histological examinations. Our conclusions are: most of the time, the diagnosis of total vitreous detachment is very difficult and the finding of a premacular membrane during vitrectomy is a frequent event.

Adolescent↗
PubMed1994

[Failures in primary surgery of retinal detachment with cerclage].

In a retrospective study we analysed 30 unsuccessful circumferential buckling operations being performed in the years 1990 and 1991 as primary interventions on simple retinal detachments without PVR, directing our attention to the cause of the failure. 13 eyes (43%) showed simple retinal detachments with holes located anterior (20%) or posterior (23%) to the circumferential buckle. In 12 of these eyes (40%) the retina could be reattached permanently by a re-operation with a second scleral buckling procedure. Another 15 eyes (50%) showed retinal holes not being sealed by the circumferential buckle. In addition, however, the retina in these eyes was kept from reattachment by a PVR grade C or D at the time of the re-operation. In 9 eyes (30%) of this group reattachment could be achieved after vitrectomy with endotamponade, in 6 eyes (20%) the retina could not be reattached. Only 2 eyes (7% of all patients) showed a PVR detachment without detectable retinal breaks. Thus, failures of primary circumferential buckling operations in numerous cases are caused by either inadequate surgical procedures or by a poor surgical technique.

Adolescent↗
PubMed1993

[Radical conjunctivectomy in therapy of malignant melanoma of the conjunctiva].

BACKGROUND: In tumor excision of large malignant melanomas of the conjunctiva or in the excision of widespread precancerous melanosis the development of symblepharon is a threatening complication after conjunctivectomy, especially if the conjunctival fornix is afflicted. PATIENTS: Three patients with suspected nodular melanoma and surrounding precancerous melanosis of the conjunctiva were treated by extended excision of the conjunctiva. Instead of a conjunctival graft, spontaneous epithelization under the protection of an 'Illig' contact lens was achieved. After this, two patients with histologically proven malignant melanomas were treated by beta-ray radiation with 90-Strontium. RESULTS: Within four weeks after the excision a complete epithelization of the wound occurred and the functional as well as the cosmetic results were very satisfying. During the follow-up between 12 and 22 months no recurrence of the melanomas and no formation of symblepharon was observed. CONCLUSIONS: With regard to these results extended tumor excision without conjunctival graft seems to be a reasonable therapy for large nodular melanomas and widespread melanosis, while the application of an 'Illig' contact lens avoids the formation of symblepharon.

Adult↗
PubMed1993

Immune function in alcoholism: a controlled study.

Several studies have shown an increased risk for infection and cancer in alcoholic patients. The mechanisms for such observations remain largely unknown. In an effort to investigate the possibility of immunological dysfunction in alcoholism, we studied three immune parameters in 47 hospitalized chronic alcoholic patients and 47 age- and sex-matched normal controls. The immune measures were: (1) lymphocyte phenotyping, with estimates of percentages of T cells, B cells, T helpers, T suppressors, natural killer (NK) cells, and cells carrying the activation markers IL2R1 and I2; (2) NK cell activity; and (3) lymphokine-activated killer cell activity. Results indicate a significant increase in the IL2R and I2 lymphocyte markers in alcoholic patients compared with matched controls. We also found a nonsignificant trend for a decrease in the percentage of suppressor T cells in the alcoholic group, as well as a trend for a negative correlation between the percentage of T suppressor cells and age. There were no significant differences in either NK or lymphokine-activated killer cell activities between the two groups. Furthermore, there were no significant associations between duration and intensity of alcohol consumption and any of the immune measures. These results suggest subtle alterations in immune regulation in alcoholic patients that cannot be explained solely on the basis of duration and/or amount of alcohol consumed.

Adult↗
PubMed1993

[Pupillary dilatation with Eckardt iris retraction sutures within the scope of vitreoretinal surgery. A follow-up study].

In cases of complicated vitreoretinal surgery, maximal mydriasis is necessary. Preexisting or intraoperatively occurring miosis in aphakic eyes can be remedied by the iris suture by Eckardt. In our hospital, the iris suture technique was carried out in 31 cases. The postoperative situation depends on the extent of retraction of the iris sutures and the general course of the disease. At maximal retraction, the iris is forced against the ciliary body, causing persisting synechias; therefore, to us it seems important to separate all synechias after opening the iris sutures. The formation of anterior loops is also possible. Thus, it is essential to release the endangered segments behind the ciliary body and at the base of the vitreous body from tractive elements immediately after opening the iris sutures. Based on our present experience, we think non-maximal retraction of the iris is desirable. It offers enough view of the fundus and reduces the complications mentioned above.

Diabetic Retinopathy↗
PubMed1992

[Choroid ganglioneuroma in childhood].

The authors report on a case of a 4 1/2-year-old male child, who was referred because of a convergent microstrabisms of the right eye combined with amblyopia and minimal anisometropia and progressive decrease of the visual function from 0.6 to 0.05 although occlussion-therapy was performed. Funduscopy showed a melanoma-like choroidal tumor temporal-inferior of the macula with shallow retinal detachment and severe cellular vitreal infiltration. Because of the progression the tumor was resected by the transscleral technique of Foulds (1983). Histology showed a ganglioneuroma of the choroid, which has not been reported in this localisation up to now. Usually it is found in the retroperitoneal area and in the mediastinum, specially in case of neurofibromatosis (Recklinghausen). This disease could not be objectified in this meanwhile 7-year-old boy. At the last control visual acuity was 1/20, ophthalmoscopy showed gross streaky depigmentation in the macular region, the retina was attached.

Child, Preschool↗