Fortschritte der Ophthalmologie : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft最新文献

Two main arguments have stimulated the development of hydrogel and silicone lenses: flexibility allows folding and thus insertion through a small incision, and inertness promises excellent biocompatibility, possibly surpassing that of PMMA. However, as long-term performance remains to be established, these implants cannot yet be considered a routine alternative. Clinical studies are mandatory to document their advantages and any disadvantages, especially as few of the reports already published on experience with such lenses do not give an objective picture of the current status: the surgical techniques used and the observation criteria applied differ and were sometimes inappropriate. In addition, the series are too small and the follow-up studies too short to allow valid conclusions. In this paper, following the description of the materials and designs and of the implantation techniques available for flexible lenses, a review of the pertinent literature and the author's own experiences is reported. This is based on 800 implantations performed over a period of 4 years. Monobloc designs with flange haptics (IOGEL, STAAR) have been found to perform best. The Faulkner folder has proved to be optimal, allowing for easy and atraumatic folding and insertion. Within the eye, the lens is safely guided and released. Bag placement of appropriately styled lens models is strongly recommended, since sulcus-placed lenses have sometimes shown either iris bulging or decentration and windshield-wiper or propeller phenomena. The capsular edge should be smooth and the capsular opening well centered and round in order to guarantee stable fixation and symmetrical compression.(ABSTRACT TRUNCATED AT 250 WORDS)

Thrombospondin (TSP), a platelet-derived protein of the integrin-binding family with adhesive and mitogenic properties was localized in surgically obtained epiretinal traction membranes from patients with traumatic (7/8) and idiopathic (8/8) proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR) (6/8). Using double-label immunofluorescence techniques, we demonstrated co-localization of TSP with the endothelial cell marker, von Willebrand factor, in PDR; however, only a minority of labeled macrophages showed simultaneous staining for TSP. Therefore, macrophages are probably not a major source of TSP in PVR. We demonstrated co-distribution of blood coagulation factor XIII and two of its cross-linking substrates, fibronectin and TSP, in epiretinal membranes, as well as the detection of plasmin and presumably plasmin-induced TSP breakdown products in physiologic and pathologic vitreous. These results suggest that the coagulation system has a functional role in proliferative retinal disorders and imply that the application of inhibitors of the coagulation cascade like heparin may be a potential therapeutic approach.

The structure and dynamics of acoustic shock waves generated with a 193-nm ArF-excimer laser pulse (20 ns) in corneal photoablation were investigated using piezoelectric transducers (PVDF foily). The shock waves passed through the cornea at the speed of sound (1630 +/- 120 m/s). The duration of the acoustic half-value thickness was approximately 60 ns. At clinically relevant laser energy densities (200 mJ/cm2) the amplitude of the shock-waves was 80 bar. At higher energy densities (500 mJ/cm2) the amplitude reaches 150 bar. When laser pulses were applied with a spot size of 100 microns the amplitude of the acoustic transient decreased inversely with the distance to the interaction zone. At large beam diameters (4 mm), however, even at a distance of 3 mm from the interaction zone no significant decrease of the shock-wave amplitude could be found. It is assumed that the mechanical stress involved in laser-induced acoustic shock-waves may be the cause of cellular alterations and the structural damage to adjacent collagen layers leading to the onset of postoperative scar formation.

Coats disease, an idiopathic condition of unknown etiology, includes teleangiectatic and aneurysmatic retinal vessels in association with massive subretinal exudation. Progression to retinal detachment caused by prolonged subretinal exudation means a poor prognosis. Retinal detachment surgery had always been controversial. Twelve patients (aged 7 to 48 years) with retinal detachment and Coats' disease were treated by various operations (cryotherapy, 4X; episcleral buckle, 2X; vitrectomy and gastamponade, 3X; vitrectomy and silicone-oiltamponade, 2X). One case (cryotherapy and cerclage) failed and went on to retinal detachment. In the other 11 cases the retinal was reattached successfully. However, peripheral, small areas remained detached, caused by persistent deposits of subretinal exudation. This means that the underlying Coats' disease is still active and must be treated by laser coagulation. It must also be monitored carefully, to keep an eye on the preretinal vitreous activities leading to detachment.

Experimental autoimmune uveitis (EAU) is induced in rats by active immunization with retinal S-Antigen (S-Ag) in complete Freund's adjuvant. In contrast, oral administration of an antigen induces specific suppression. We investigated the potential of oral administration of S-Ag for the treatment of EAU. Prior to active immunization rats received 3 x 1 mg S-Ag orally. In contrast to untreated controls, the treated rats were significantly protected from EAU, as determined by clinical and histological examination. Lymphocytes from treated rats showed no proliferative response to S-Ag in vitro, but had a normal proliferative response to other antigens. CD8-positive T cells from S-Ag-fed rats inhibited the proliferation of an antigen-specific uveitogenic T-cell line in vitro. Moreover, the intensity of the inflammatory reaction to active immunization could be suppressed when feeding was started after the active immunization. These data show, that oral administration induced suppression, which provided significant protection from the development of uveitis.

In 28 cases of cytomegalovirus retinitis being treated with ganciclovir we examined the relative value of planimetry and conventional investigative methods, such as visual field examination and serial fundus photographs in determination of the development of retinitis. Planimetric evaluation was not possible in 11 of the 28 cases because of technical problems inherent in the method. In 17 cases we found no correlation between visual acuity, visual field and area of retinal necrosis evaluated by planimetry. This shows the low value of visual acuity tests and planimetric evaluation of routine fundus photographs in the examination of the development of common retinitis. In selected cases with primary visual acuity of less than 1/10 (e.g., in optic nerve involvement) the planimetry of fundus photographs seems to yield more information than the standard ophthalmological routine examinations.

Erythrocytes bind fluorescein to their surface, but they do not take up the dye intracellularly during fluorescein angiography. The cells are therefore hypofluorescent compared to blood plasma. Due to the high velocity of red blood cells in retinal vessels, this phenomenon has not been observed during conventional angiography. Scanning laser ophthalmoscopy, however, allows imaging of the retina with a very high temporal resolution. The exposure time of the scanning laser beam for a single erythrocyte is in the range of only 100 ns. Therefore, scanning laser ophthalmoscopy permits imaging of fast-moving red blood cells in large retinal vessels. Pathologically reduced blood flow is clearly visible and can be measured with digital image analysis. The values found in three patients with vascular occlusions were between 0.1 and 1.8 mm/s. In cases with intact circulation, digital image analysis was not sufficient to measure red blood cell velocity. Even if a velocimeter that permits semiquantitative comparison between erythrocytes and moving black dots is used, superimposed on the angiogram, reliable results can only be obtained in cases with reduced red cell velocity. Nevertheless, for the clinician observation of erythrocyte flow during scanning laser angiography is a new and fascinating tool.

When performing a pneumatic retinopexy, air or gas is injected into the vitreous cavity to reattach a primary, rhegmatogenous retinal detachment. SF6 gas, for examples, remains in the vitreous cavity for up to 2 weeks before it is completely absorbed. It is conceivable that the injection of SF6 gas into the vitreous cavity interferes with lens metabolism, thus causing opacities of the lens. Even minor early changes in lens transparency can be monitored by Scheimpflug photography. Two months after performing a pneumatic retinopexy, 31 out of 100 consecutive eyes showed a loss of lens transparency, which was not pronounced or statistically significant. Six months after surgery the loss of transparency was more pronounced in all lens layers, increasing from the front to the back. The increment was statistically significant for the anterior lens cortex. Further investigations are needed to determine whether lens changes are the result of the intraocular tamponade with SF6 gas or are related to other factors, such as the surgical maneuver itself.

We report three patients with recurrent Chlamydia-associated conjunctivitis. The clinical course of the Chlamydial infection was documented by positive conjunctival smears (direct immunofluorescence staining) and the evaluation of the IgA-titer in the sera (immunoperoxidase assay). The recovery of the ocular symptoms after therapy onset correlated well with the negative results of the conjunctival smears and the decrease in IgA level in the sera. The recurrence of the conjunctivitis was accompanied by an increase in the IgA titer in the sera of all three patients and the presence of Chlamydial elementary bodies in the conjunctival scrapings in two cases. Three patients showed immunologic pecularities: two had an allergic diathesis; the third patient developed Wegener disease 3 months after the onset of ocular inflammation. Inclusion bodies or Chlamydial DNA can persist in conjunctival cells. Anderson suggested that a recurrence of active Chlamydial infection may be induced by external causes, which lead to reconstitution of elementary bodies from the persisting DNA. The extraordinary immune situation of our patients might be one cause of the recurrent conjunctivitis.

The treatment of optic neuritis (ON) with corticosteroids has been controversial for many years. None of the previous studies with the usual dosage of steroids or ACTH has proven that this therapy is beneficial. However, these studies did not apply sensitive parameters for assessing the course of ON. The aim of this study was to examine the effect of corticosteroids using subtle parameters. The study design emphasized: 1. strict criteria for patient selection; 2. frequent controls during the initial period of the disease, follow-up for 1 year; 3. double-blind conditions with randomized groups; 4. assessment of the course with sensitive parameters, including visual acuity, visual evoked potentials (VEP) and the Tübingen Flikker Test, also called the Aulhorn Flicker Test, which monitors the activity of the ON. These last two tests were used for the first time in a controlled treatment study in ON. Thirty-eight patients with acute ON were treated orally in a double-blind procedure with either methylprednisolone (initially 100 mg daily, reduction every 3 days) or with vitamin B1 (100 mg thiamin daily) in the control group. The results of the Flicker Test and VEP showed a trend toward faster recovery under prednisolone within the first few weeks after onset of the disease. After 1 year none of the parameters examined showed any difference between the two groups. Thus, although prednisolone treatment in the dosage mentioned above seems to speed up recovery in the initial phase in some patients, no long-term benefit could be demonstrated.