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Biomedical subjects

J Strobel

Publications and source records attributed to J Strobel.

At least 19 recordsLinked to original sources
PubMed1992

Effect of heparin surface modification of polymethylmethacrylate intraocular lenses on signs of postoperative inflammation after extracapsular cataract extraction. One-year results of a double-masked multicenter study.

PURPOSE: A heparin surface modified posterior chamber intraocular lens (IOL) was compared with a conventional polymethylmethacrylate (PMMA) IOL regarding postoperative complications caused by inflammation. METHODS: Five hundred twenty-four patients from 10 different centers were included in a parallel group, double-masked, multicenter study. RESULTS: The cumulative number of patients with inflammatory cellular deposits on their IOLs during the first postoperative year differed significantly in favor of the heparin surface modified group, with 29.8% of the patients having cellular deposits compared with 48.8% of patients in the control group. Cellular deposits were observed most frequently at 3 months after surgery, and the difference between the groups was most pronounced and statistically significant at this time. The same results were seen at 1 year, but the difference was not significant. The number of cellular deposits per patient, however, was significantly lower in the heparin surface modified group at 1 year. Cumulatively, there were significantly more patients with posterior synechiae in the PMMA group than in the heparin surface modified group during the 1-year follow-up. Complications were few and comparable between the groups. CONCLUSION: The results of this study indicate that heparin surface modification reduces the inflammatory response to PMMA IOLs.

Adult↗
PubMed1992

[In vivo autofluorescence. Measurements of human crystalline lenses with cataract and normal findings after excitation with monochromatic light].

In 25 eyes with nuclear cataract, 18 eyes with posterior subcapsular cataract, 25 eyes with cortical cataract, and 23 eyes without any pathological lens changes, the maximal fluorescence intensity was determined after excitation with monochromatic light at 365 nm, 405 nm, 436 nm, and 485 nm. The coefficient of variation was smaller than 5%. All eyes with cataract underwent cataract surgery a few days after the fluorescence measurements. The fluorescence spectrometer, especially constructed for in vivo measurements, consists of a modified slit lamp (Zeiss 75 SL) and an optical multichannel analyser (OMA) for gauging the data. The clinical trial was undertaken to determine whether, considering the influence of age, there is a difference between the fluorescence intensities in eyes with the above named cataracts and noncataractous eyes. The data were analyzed to determine the effect of age upon fluorescence intensity for all excitation wavelengths in both cataractous and noncataractous eyes. Age had an influence on the fluorescence intensities for all four excitation wavelengths. Assuming that the influence of age was not dependent on the state of the lens, it was quantified for all measurements and an "age-corrected" fluorescence intensity was calculated. The statistical analyses of these "age-corrected" fluorescence intensities revealed a significant difference (P < 0.001) for all of the types of cataracts examined and for normal eyes. The cataract types examined and the normal eyes showed differences in their fluorescence feature. To assess the fluorescence intensities obtained after excitation with the wavelengths mentioned above, one must take into consideration the influence of age on the measurements.

Adult↗
PubMed1992

[Measuring scattered light with the Opacity Lensmeter 701 in normal eyes and eyes with cataracts. Correlation between scattered light and cataract-induced vision loss].

In 50 eyes with nuclear cataract, posterior subcapsular cataract and cortical cataract and 34 normal eyes, the amount of scattered light was determined using the Opacity Lensmeter 701 to determine its accuracy in distinguishing between clear and cataractous lenses. Taking as a basis the manufacturer's statement that normal lenses show Opacity Lensmeter readings of less than 25 and that cataractous lenses show Opacity Lensmeter readings of more than 30, 94% of the nuclear cataract cases, 62% of the posterior subcapsular cases and 66% of the cortical cataract cases were identified as being pathologically opaque. Of the normal eyes, 88% had an Opacity Lensmeter reading of less than 25. Among the types of cataract examined, a significant linear relationship (P < 0.05) between visual acuity loss due to cataract and scattered light measurements could be found only in eyes with nuclear cataract, with the individual results heavily scattered around the linear regression. In the case of nuclear cataracts, measuring scattered light with the Opacity Lensmeter is suitable for making general statements on visual loss due to cataract for a whole group of patients. However, in individual cases the results can only be used together with other clinical examinations.

Adult↗
PubMed1992

[Computerized videokeratoscopy. Indications for postoperative suture removal].

Twenty-three patients who had a high degree of postoperative astigmatism (3 D) after extracapsular cataract extraction were examined in a prospective study with a computerized videokeratoscope. Sutures were removed within the first 3 months postoperatively, and an examination with the videokeratoscope was performed at the same time. In addition, corneal power was measured with a keratometer for comparison. A comparative map demonstrating the change in corneal shape can be obtained by simple subtraction of the pre- and postoperative keratographs (color-coded topographical maps). Immediately after suture removal the corneal curvature was flattened in the steepest meridian (3 mm and 5 mm zone), resulting in an average net change in cylindrical refraction of -1.3 (+/- 1.7)D. The steepest meridian moved slightly in a counterclockwise direction (-5.79 +/- 29.4 degrees). The topographical analysis of all cases showed that suture removal along the steepest meridian reduced astigmatism by flattening the steepest meridian and steepening the flattest meridian. As the peripheral cornea becomes steeper, the central cornea flattens in a meridian. Morphologically, three different patterns were found. In 52% the reduction in astigmatism was "symmetric", in 21% it was "round", and in 26% it was "irregular". As a result of the study, a topographical model of the cornea will be given, showing the average net change in diopters power at various locations on the surface of the cornea. These results cannot be described by the use of ordinary keratometers.

Astigmatism↗
PubMed1991

[Concentration of non-steroidal, anti-inflammatory topical agents in the aqueous humor].

In a prospective randomised study we tested two non-steroidal anti-inflammatory medications clinically in a group of 40 eyes. 20 eyes received topically administered indomethacin and another 20 flurbiprofen eyedrops. Before we started the planned extracapsular cataract extraction we performed a puncture of the anterior chamber and aspirated a small volume of anterior chamber fluid. We examined the concentrations of the applied drugs in the aspirated volume. The concentration of indomethacin is 7-9 times higher than that of flurbiprofen.

Administration, Topical↗
PubMed1991

[Concentration of locally applied Indometacin eyedrops for the inhibition of prostaglandin synthesis in the eye].

Indomethacin is well known as local eye drug for the prevention of cystoid macular oedema. The concentration is 50 mg/5 ml. Another inhibitor of the prostaglandin synthesis is flurbiprofen; its concentration is 1.5 mg/5 ml. Indomethacin is a suspension and available in different concentrations dependent on the shaking procedure. We measured the concentration of indomethacin in one single eyedrop from a full bottle, half full and a nearly empty bottle. After correct shaking the concentration of indomethacin was between 48 and 53 mg/5 ml.

Indomethacin↗
PubMed1991

[Quantitative studies of protein and cell concentrations in the anterior chamber in cataract surgery with therapy using steroidal and non-steroidal antiphlogistic drugs].

In a prospective, randomized double-blind study, the anti-inflammatory effects of indomethacin and flurbiprofen were examined. The operation performed was extracapsular cataract extraction. For the pre- and postoperative measurement, the Laser Flare Cell Meter was used. In 76 eyes the flare and cell concentrations were measured quantitatively. It was found that, dependent on the postoperative time interval, indomethacin is more effective in reducing post-operative inflammation than flurbiprofen.

Anterior Chamber↗
PubMed1991

[Glare and contrast with diffraction intraocular lenses].

The quality of vision in patients with a diffractive multifocal intraocular lens was tested and compared to monofocal IOLs and to eyes with a beginning cataract. An automatic computer-assisted visual acuity and contrast-sensitivity test was used. Diffractive IOLs showed reduced contrast sensitivity in both dark contrast testing and bright contrast testing. The differences from monofocal IOLs were not statistically significant. Glare sensitivity was of the same degree in both IOL groups. In additional, visual acuity under reduced contrast conditions was measured at the Ocutrast with and without glare. There was no significant difference between IOL groups. The results obtained showed that contrast sensitivity with diffractive IOLs is not as good as with monofocal IOLs. In this study no significant differences were found.

Aged↗
PubMed1991

[Stereotactic evacuation and early rehabilitation in space-occupying cerebral hemorrhage].

The choice of treatment in intracerebral hematoma remains controversial as long as there are no prospective, randomized trials from multiple centers. Recent experiences showed a lower mortality rate after stereotactic evacuation of intracerebral hematoma. However according to the present study (60 patients) the quality of survival and duration of hospital stay seems to be dependent on early and intensified rehabilitation and physiotherapy.

Cerebral Hemorrhage↗
PubMed1990

[Local anesthetics in the aqueous humor in local anesthesia of the eye].

Local anesthetics injected retrobulbarly are detectable in the aqueous humor. From 40 patients who received a total dose of 140 mg lidocaine, 15 mg bupivacaine, and 30 mg etidocaine, samples of aqueous humor were taken between 30 and 90 minutes after administration (average 57 minutes). The mean lidocaine concentration was 1.02 micrograms/ml, that of bupivacaine 0.075 micrograms/ml. Etidocaine, used only for facial nerve block in front of the ear, could not be detected in the aqueous humor. All three substances were found in the central venous blood. It therefore appears unlikely that any of them are transported via the blood-aqueous barrier, whether actively or passively. Local anesthetics can inhibit corneal cell proliferation and result in lens opacification when administered into the conjunctival sac. It may be that local anesthetics detected in the aqueous humor have similar effects resulting from contact with the cornea and lens.

Aged↗
PubMed1990

[Cataract diagnosis using scattered light at 700 nm].

The present study was undertaken to determine whether the scattered light of lenses measured with the Opacity Lensmeter 701 can be used for objective, quantitative assessment of lens opacities, and how far pupillary diameter and the type of lens opacity affect the measurement. Visual acuity and scattered light were determined in 150 eyes with the Opacity Lensmeter set at 700 nm. In the group with nuclear cataract there was a significant correlation between visual acuity and the amount of scattered light measured by the Lensmeter. In the groups with cataracta scutellaris posterior and cortical cataract there was no significant correlation between visual acuity and scattered light measurements. While the Interzeag Opacity Lensmeter 701 is capable of furnishing data on fairly large populations with nuclear cataract, it is of limited value for assessing individual cases. The influence of pupillary diameter on the scattered light measurement was examined in 50 selected eyes. In all 30 of the eyes with cataract, significant correlations were found between pupillary diameter and scattered light measurements, while this was the case in only 10 of the 20 normal eyes. Therefore, when measuring stray light in cataract cases, the pupillary diameter should be stated.

Cataract↗
PubMed1990

[Special intra-ocular lenses].

Intraocular lens (IOL) implantation is the method established worldwide for visual rehabilitation following cataract surgery. IOL's with particular characteristics and/or for special purposes are available for clinical or experimental use. Bifocal and multifocal IOLs have two or more foci for simultaneous far and near vision. The first clinical results are promising. The theoretically expected disadvantages, i.e., reduced contrast sensitivity or reduced visual acuity under reduced contrast conditions, have not yet been found in clinical studies. In cases of age-related macular degeneration, IOLs with a high negative diopter power in the center can be implanted as part of a Galilei telescope. By using high-plus power spectacles, a 2.5x to 4x magnification and a wide field of view can be achieved. Clinical investigation has started recently. Intraocular lenses for the correction of high-grade myopia are being tested by some surgeons. These lenses are made to be implanted in phakic eyes with a clear crystalline lens. Angle-supported and iris-fixated types are under investigation. Longterm results will show the clinical efficacy and safety. Other special intraocular lenses are iris-color lenses and a polymethymethacrylate (PMMA) iris diaphragm.

Humans↗
PubMed1990

[In vivo examination of aqueous humor for cells and protein in clinically silent anterior uveitis before surgical interventions].

The laser flare cell meter is a new device for measuring flare and cells in the anterior chamber. In 100 eyes we used this device to measure flare and cell counts. We found that eyes with former uveitis and no clinical signs of acute or earlier uveitis have more flare and more cells in the aqueous humor. This is important for IOL implantation and follow-up studies to determine the best way to perform eye surgery.

Aqueous Humor↗
PubMed1989

[Preoperative use of suction cup oculopression in comparison with Vörösmarthy oculopression].

In contrast to Vörösmarthy oculopression (VOP), suction-cup oculopression (SOP) is "pure" oculopression without compression of orbital tissue. Prior to 44 cataract operations with posterior chamber lens implantation, the authors performed SOP (negative pressure - 110 mm Hg) or VOP (level of oculopression 30 mm Hg) of the same duration (average 26 min). Before oculopression, a retrobulbar injection (RBI) was performed for local anesthesia. The intraocular pressure (IOP) was decreased by 14 mm Hg to 3.9 and 4.9 mm Hg after SOP and VOP, respectively. After VOP, the iris-vitreous diaphragm was more frequently judged to be concave, i.e., vaulted against the retina, than after SOP (standardized questionnaire). After RBI + SOP, a post-injection of anesthetic was necessary in three cases; no additional injection was required after RBI + VOP. In conclusion, identical preoperative reductions in IOP can be achieved with SOP and VOP. Regarding the form of the iris-vitreous diaphragm and the frequency of post-injection, the differences between the two methods may be related to the lack of orbital compression during SOP.

Aged↗
PubMed1989

[Natural fluorescence of nuclear cataract lenses and melanomas of the eye].

For various reasons, it is desirable to have an objective cataract classification system that does not depend on either the opinion of the physician or the patient. Since both highly molecular protein aggregates and chromophores are formed in cataractous lenses, which fluoresce under suitable stimulation, we have developed a fluorescence apparatus that illuminates the lens with five monochromatic wavelengths between 350 and 500 nm in situ. The fluorescence spectrum is recorded up to 100 ms with an optical multi-channel analyzer. This fluorescence method is non-invasive and does not harm the eye; it also uses the native fluorophore. The set of fluorescence spectra obtained by this method describes the condition of the cataractous lens both quantitatively and qualitatively. Because of the sensitivity of the method, it can also be used to assess the disease objectively in the early stages and to test and determine the effectiveness of anti-cataract drugs. Another use was discovered by using the fluorescence measurements for the diagnosis of malignant melanomas. With this equipment, melanomas in the eye and the surrounding area can be diagnosed both rapidly and precisely.

Cataract↗
PubMed1989

[Measuring lens opacity with the Opacity Lensmeter 701].

The Opacity Lensmeter 701 is a new instrument to quantify the opacity of the lens. The stray light scattered on the lens is measured and the amount depends on the density of the cataract. In 85 patients who underwent cataract surgery, both visual acuity and lens opacity were measured before surgery. After implantation of a lens, the visual acuity was tested again. There was a significant correlation between the opacity values and a cortical cataract. The correlation was lower (p = 0.0696) for eyes with nuclear cataracts. No correlation was found between a posterior subcapsular cataract and the opacity values measured.

Cataract↗
PubMed1989

[Automatic evaluation of visual functions using a computer].

Many different tests for visual acuity, glare and contrast sensitivity, even by computer, are known. We developed a new computer system that is directed by the patient who works with a joystick. A special overlay computer program receives the answers given by the joystick, calculates the information on the screen and provides a new combination of background illumination, optotype position, color, contrast and enlargement. With this automatic test we examined cataract patients before and after the operation. After the operation the patients have better visual acuity and less sensitivity to glare- and contrast in both the dark and light.

Cataract↗