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Biomedical subjects

O E Schnaudigel

Publications and source records attributed to O E Schnaudigel.

At least 19 recordsLinked to original sources
PubMed1992

[Image quality of various types of intraocular lenses (mono-, bi- and multifocal) in air and water].

Most of the monofocal intraocular lenses tested in air and water showed good-to-high resolution in water. There was low resolution in the outer zone of the image in some models. The bifocals tested had a lower resolution efficency with less contrast and change of colors. The diffractive IOL had poor central resolution efficiency with changing colors and double vision. There was a spherical change like a fish-eye. When tested in air there was paracentral double vision in the diffractive IOL with a change of color bands.

Humans↗
PubMed1991

[Changes in the visual field caused by lens opacities].

60 eyes with advanced opacity of the lens nucleus and a corrected visual acuity of at least 0.1 have been examined by Octopus perimetery before and after a cataract extraction with posterior chamber lens implantation. 20 eyes had chronic glaucoma with glaucomatous alterations of the optic nerve head. Our purpose was to determine the effect of lens opacities on the result of automated perimetry especially in view of glaucomatous field defects. The influence of the cataract on the differential light threshold in the whole field (30 degrees) area showed a wide variance. The calculated visual field indices loss variance (LV) and corrected loss variance (CLV) did not clearly separate glaucomatous from cataractous field changes. Often an exact analysis of the numerical printout of the visual field helps in finding of localized glaucomatous field defects.

Adult↗
PubMed1990

[Anatomy of the ciliary sulcus].

The space between the posterior surface of the base of the iris and the anterior surface of the ciliary body - the ciliary sulcus - and the capsular bag are the sites for a posterior chamber lens implant after extracapsular cataract extraction. In human cadaver eyes and in eyes after cataract extraction, the exact topographical relationship of the ciliary sulcus and the surrounding tissue was analyzed. The anatomical findings and important variations are documented by light microscopy and macrophotography and the relationship to lens implantation is discussed.

Ciliary Body↗
PubMed1989

Comparison of different models for the testing of pilocarpine eyedrops using conventional eyedrops and a novel depot formulation (nanoparticles).

An objective in the development of ophthalmic formulations is the use of in vitro or animal models that closely resemble the clinical situation. For this reason, experiments with conventional pilocarpine nitrate eyedrops and a depot formulation of pilocarpine nitrate sorbed to poly (butylcyanoacrylate) nanoparticles were carried out. In vitro, the diffusion of pilocarpine through bovine cornea was measured using Edelhauser cells. In vivo, the rabbit aqueous humor concentration of pilocarpine and miosis were determined after application of the above formulations. In addition, intraocular pressure was measured. Since pilocarpine has little influence on intraocular pressure in healthy rabbits, the pressure had to be increased artificially. Three models were employed that are described in the literature, namely, the betamethasone model, the alpha-chymotrypsin model, and the water-loading model. Pilocarpine could be loaded onto nanoparticles by 15% but was rapidly released from the nanoparticles based on the bovine corneal experiment. Nanoparticles only enhanced the aqueous humor concentration at 30 min; this increase, however, led to a considerably extended period of miosis as well as a reduction in intraocular pressure. The duration of the action and the intensity of the response were different among the three models tested. According to the present results, the betamethasone model seems to represent the best correlation to the clinical situation.

Animals↗
PubMed1989

[Intraocular ossification].

Following a general introduction to the problem of heterotopic bone formation the pathogenetic stages of intraocular ossification are described. Intraocular ossification was found in 30 (7%) of 423 eyes enucleated between 1974 and 1984. In 60% of the eyes the ossification was associated with trauma, in 25% with chronic uveitis. Bone formation started between four and 44 years after the onset of ocular disease and in most cases originated in the retinal pigment epithelium.

Adolescent↗
PubMed1989

[Evaluating the postoperative depth of the anterior chamber in primary extracapsular cataract extraction and intraocular lens implantation].

To evaluate the depth postoperatively of the anterior chamber, a second biometry by ultrasound was done in 100 eyes 6-12 months after cataract extraction and IOL implantation (sulcus fixation). The aim was to compare the depth of the anterior chamber preoperatively with that measured postoperatively. The measurement showed a middle anterior chamber depth of 3.42 mm preoperatively and 3.67 mm postoperatively. This means that there was a mean increase in the anterior chamber depth of 0.25 mm.

Anterior Chamber↗
PubMed1988

[Carteolol: general practice-oriented assessment of the effectiveness and tolerance of a new beta-blocker in the treatment of glaucoma].

During an open multicenter field study the new beta-blocking agent Carteolol, in 1% and 2% solution, proved to be effective and safe in the treatment of 178 patients suffering from glaucoma. On average, IOP was lowered by 5.8 to 18.7 mm Hg in nontreated and by 4.8 to 17.8 mm Hg in pretreated patients. In more than 90% of the cases both the patients and the investigators judged the treatment to be good, or better than the previous therapy. Side affects occurred in less than 3% of the cases.

Carteolol↗
PubMed1986

[Glaucoma visual fields and filtering operations].

Visual field defects already existing in 81 eyes prior to goniotrepanation (Elliot-Fronimopoulos) were followed up for up to 84 months postoperatively. In 11 eyes there were slight peripheral limitations due to cataract formation. In all of the other cases the visual fields were unchanged.

Follow-Up Studies↗
PubMed1986

[Defective artificial lenses].

The authors found the following defects in sterile-packed intraocular lenses, ready for implantation: the positioning holes had sharp edges; the lens surfaces were scratched from polishing and drilling; the lens loops were distinctly deformed. Following a description of these defects the possible clinical complications are discussed.

Humans↗
PubMed1984

Pattern electroretinogram and visually evoked cortical potentials in glaucoma.

Electroretinograms (P-ERG) and cortical potentials (P-VECP) evoked by checkerboard patterns were examined in patients with defects of the ganglion cell and nerve fiber layers due to glaucoma. Only a few patients exhibited a prolonged latency in the P-VECP, whereas in the P-ERG all patients with papillary and visual field defects revealed a significantly attenuated amplitude. Since there is a substantial fluctuation in the assessment of papillary excavation and visual field, the P-ERG offers a further means of evaluating and follow-up of retinal function in glaucoma patients.

Aged↗
PubMed1984

The pattern evoked electroretinogram associated with elevated intraocular pressure.

Electroretinographic responses to pattern-reversal stimuli (P-ERG) were recorded in eight patients with protracted elevation of intraocular pressure. Pressures of bigger than 30 mm Hg result in marked amplitude reductions in the P-ERG. The observed changes probably reflect the impaired function of retinal ganglion cells caused by decreased oxygen supply.

Adult↗