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Biomedical subjects

K W Jacobi

Publications and source records attributed to K W Jacobi.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Endothelial cell loss after phacoemulsification and 3.5 vs. 5 mm corneal tunnel incision].

This prospective study was performed to compare the central endothelial cell loss (ECL) after phacoemulsification and 3.5 with 5 mm temporal clear-corneal incision. Moreover, the influence of ultrasound time and power on postoperative endothelial cell density was evaluated. PATIENTS AND METHODS. Sixty-two patients (age 71 +/- 7.7 years) without corneal pathology were operated by phacoemulsification (Storz, Premiere) with a temporal, self-sealing, two-step clear-corneal incision followed by posterior chamber IOL implantation under viscoelastic (1% sodium hyal-uronate). Thirty-one one-piece plate-haptic foldable silicone IOLs (Chiron C10; Staar Surgical AA-4203) were implanted by an injector through a 3.5 mm incision (group A). The other 31 PMMA IOLs (Pharmacia 809P) were implanted through a 5 mm incision (group B). One surgeon performed all operations with the same technique (bimanual phacoemulsification in the capsular bag). Sutureless wound closure was performed in group A, while the wounds in patients of group B were closed with a single radial stitch. The central endothelial cell counts were recorded preoperatively, on days 2-5 and 6 months postoperatively using contact specular microscopy. RESULTS. The collective data revealed a cell loss of 7.9% (+/- 4.1 SD) on days 2-5 postoperatively and 6.7% (+/- 2.9) after 6 months. A direct linear relationship was found to exist between ultrasound time (UT) and ECL. In group A (7 patients) the ECL slightly increased from 3.5% in the first week postoperatively to 3.8% after 6 months, operated under UT < or = 1 min 30 sec. The ECL decreased from 8.2% to 6.4% after 6 months in group A (19 patients), operated under UT of 1 min 30 sec, and from 10.8% to 8.9% under UT of 2 min 31 sec-3 min 30 sec (5 patients). The ECL in group B decreased from 6.3% in the first postoperative week to 5.4% 6 months postoperatively, operated under UT < or = 1 min 30 sec (10 patients), from 8.1% to 7%, operated under UT of 1 min 31 sec-2 min 30 sec (14 patients), and from 11.2% to 10.4% under UT of 2 min 31 sec-3 min 30 sec (7 patients). CONCLUSION. Endothelial cell loss of 6.7% after phacoemulsification through a temporal clear-corneal incision compares favorably with other series in which cell loss was determined following cataract surgery with or without IOL implantation. Phacoemulsification and 3.5 mm clear-corneal incision evoked less ECL of 6.2% compared with phacoemulsification and 5 mm clear-corneal incision with ECL of 7.3% after 6 months.

Aged↗
PubMed1995

[Effects of Nd:YAG microexplosions on heparin-coated PMMA intraocular lenses].

UNLABELLED: Surface modification of intraocular lenses (IOL) have improved the quality of cataract surgery. Heparin surface-modified (HSM) IOL are implanted for special indications (e.g., recurrent uveitis, cataract surgery for children, preoperative synechia) because of decreased postoperative inflammatory reactions and higher long-term biocompatibility. Nevertheless, secondary cataract, precipitates and fibrinous membranes appear. The YAG laser is used for treatment. METHODS: PMMA intraocular lenses with or without a heparin monolayer were exposed to Nd:YAG laser. The experiment was performed under BSS using different energy levels and distances to the IOL. The heparin monolayer was stained with toluidin blue. Subsequently, the surface of the intraocular lenses was examined with light and scanning electron microscopy. RESULTS: The YAG laser marks of HSM IOL and PMMA IOL showed no morphological differences. Microexplosions and pressure waves of the Nd:YAG laser cleared parts of the heparin monolayer in the area of the laser spots dependent on energy distance to the IOL. Even "breakdown" behind the HSM IOL without any PMMA lesion shown circular destruction of the heparin monolayer. CONCLUSIONS: The heparin surface defect of HSM IOL after YAG laser treatment should be taken into consideration, because a decreased heparin effect in vivo could be possible.

Heparin↗
PubMed1995

[The anti-inflammatory effect of heparin-containing infusion solutions during phacoemulsification].

UNLABELLED: The use of heparin prevented postoperative intraocular fibrin-clot formation in the rabbit after vitrectomy and cyclocryotherapy. A low rate of postoperative intraocular inflammation was observed in our patients receiving phacoemulsification with heparin infusion solution (slit-lamp examination). To verify this effect a randomized, prospective study was performed using laser-flare cell photometry (LFCP) for measuring protein concentration in the anterior chamber. PATIENTS AND METHODS: Seventy-two patients (49-87 years of age) were randomly assigned to one of the following two surgical groups (temporal clear corneal tunnel incision with phacoemulsification): group A: foldable silicone IOL (Chiron C10), no stitch (3.5 mm incision); group B: PMMA-IOL (Pharmacia 809P) with one radial suture (5 mm incision). Fifty percent of the patients in each group received, in addition to the regular phaco infusion, 1 ml of heparin sodium (-H = without heparin; +H = with heparin). Aqueous flare was measured preoperatively as well as on days 1 and 3 following phaco + IOL with LFCP (Modell FC-1000; Kowa Company). RESULTS: In group A1 (-H) or B1 (-H) the mean flare values (in photon counts/ms) increased from a preoperative value of 7.0 +/- 1.7 (mean +/- SD) or 6.9 +/- 1.2 to 20.2 +/- 3.1 or 20.1 +/- 3.0 on the 1st postoperative day, whereas they decreased again to 13.8 +/- 2.9 or 14.8 +/- 3.1 on day 3 following surgery. In groups with heparin sodium A2(+H) and B2(+H) the flare values only increased from 7.2 +/- 1.3 or 7.1 +/- 1.3 to 12.9 +/- 4.0 or 13.8 +/- 3.8 on day 1, and decreased to 8.0 +/- 2.8 or 8.8 +/- 3.0 on the 3rd postoperative day. The mean postoperative flare values were significantly lower in the groups with additional heparin (p < 0.01). CONCLUSIONS: Heparin sodium in the infusion solution during small incision cataract surgery showed an antiinflammatory effect in the early postoperative period. There was no significant difference between the two IOL materials.

Aged↗
PubMed1994

[Effect of diffractive multi-focal lenses on contrast vision, glare sensitivity and color vision].

BACKGROUND: Due to theoretical considerations an increase in the depth of field of the diffractive IOL may be combined with a reduction in contrast sensitivity, glare sensitivity and colour perception. PATIENTS AND METHODS: A comparative analysis of both eyes was performed in ten patients with a diffractive multifocal IOL (3M 815LE) in one eye and a monofocal IOL in the other eye. Contrast sensitivity was examined by computer generated sine wave gratings of 6 different spatial frequencies; visual acuity with glare and glare sensitivity were determined under 7 different levels of field luminance; colour vision was examined using the Farnsworth-Munsell-100-Hue-test. RESULTS: Contrast sensitivity of the diffractive lens was reduced for intermediate spatial frequencies, but not for low and high frequencies. Visual acuity with glare was only reduced at maximum field luminance; no differences were found in glare sensitivity and colour perception between monofocal and multifocal. CONCLUSION: Altogether, the diffractive lens did not show a dramatic reduction in the examined visual functions compared with the monofocal IOL.

Aged↗
PubMed1994

[Systemic complications and side effects of retrobulbar anesthesia in risk patients].

BACKGROUND: Serious systemic complications with possibly lethal exit after retrobulbar anesthesia have been reported. The present study was performed to evaluate the incidence of complications after anesthesia in risk patients with pre-existing diseases. 2.8% of 3000 cataract operations in our department during October 1991 to April 1993 were performed under general anesthesia, 97.2% under local anesthesia. PATIENTS AND METHODS: 1000 anesthesia protocols of these cataract operations under retrobulbar anesthesia and facial block with anesthesia stand-by were analyzed retrospectively. After retrobulbar injection in Atkinson technique we performed a modified O'Brien facial block. The patients were assigned to five different risk groups on the basis of a special point system. RESULTS: The mean age of the patients increased with the risk group from 60.4 years in group 1 to 77.1 years in group 5. Cardiovascular, pulmonary and general risk factors appeared more frequently in the groups of higher risk. The frequency of cardiovascular complications was dependent on affiliation to risk group. The percentual frequency of cardiovascular complications increased from 1.7% in risk group 1 to 7.7% in risk group 5. Decrease of heart rate or blood pressure of more than 30%, or in combination, with the necessity of medical treatment occurred absolutely and relatively most frequently. The frequency of cardiovascular complications amounted 2.2% in the mean. Life-threatening complications with the need of endotracheal intubation or other occurred in 0.1%. CONCLUSION: The relatively high total frequency of systemic complications of 2.4% is related with age and preexisting diseases. The results underline the necessity of anesthesia stand-by in risk patients with the essential requirements for treatment of typical complications.

Aged↗
PubMed1994

[Theoretical and clinical image properties of refractive 3-zone multifocal lenses with different distribution of far and near focus].

BACKGROUND: The optic of common multifocal IOLs (MIOLs) is effecting an even light distribution to far and near focus. New MIOL designs were developed by Jacobi to improve distance or near contrast, by favouring the far or near focus with 60-70% of the light energy. For binocular implantation, an "asymmetrical" MIOL-combination is possible with accentuation of distance focus in one eye and near focus in the other eye. METHODS: By means of an optical system described by Jacobi and Reiner "artificial eyes" with the new MIOLs were implanted in 7 young healthy subjects and contrast sensitivity was measured for distance and near. Clinical implantation was performed in 46 patients and visual acuity, contrast sensitivity, depth of focus and binocular functions were determined after 6 months. RESULTS: MIOL designs with accentuation of distance vision did not show a significant reduction of distance contrast compared with a monofocal IOL. Asymmetrical binocular implantation of the new lenses resulted in a better distance and near contrast sensitivity than implantation of MIOLs with an even light distribution. Binocular functions were not impaired. CONCLUSION: Asymmetrical implantation of the new MIOLs with uneven light distribution to far and near focus enables distance vision comparable to monofocal IOLs, but with the advantage of an increased depth of focus.

Adult↗
PubMed1994

[Mesoptic vision in multi- and monofocal pseudophakia and in phakic control eyes].

UNLABELLED: The mesopic visual acuity (MVA) after intraocular lens (IOL) implantation is reduced compared to phakic patients of the same age. However, previous studies from our clinic have shown no significant MVA difference between multi- and monofocal IOLs. In the present study (with the patients matched exactly for age), this topic was reevaluated. PATIENTS AND METHODS: We investigated three groups, each consisting of 28 persons, 51 to 60 years of age. Group I consisted of healthy phakic volunteers, group II of patients 3 months after cataract extraction and implantation of a monofocal posterior chamber IOL (Pharmacia 720A) and group III of patients 3 months after implantation of a diffractive multifocal posterior chamber IOL with biconvex optic configuration (3M 825X). The MVA was examined using the "Ocutrast," described by Nowak. The Ocutrast, a modification of the Mesoptometer II, provides a field luminance of 1 cd/m2 and a contrast of 1:23 between test optotype and background; the intensity of illumination under glare conditions amounts to 0.35 lx at the level of the pupil. RESULTS: The MVA without glare amounted to 0.50 +/- 0.12 (group I, healthy phakic eyes), 0.45 +/- 0.15 (group II, monofocal IOLs) and 0.32 +/- 0.11 (group III, multifocal IOLs). The MVA with glare amounted to 0.47 +/- 0.08 (group I), 0.35 +/- 0.12 (group II) and 0.24 +/- 0.10 (group III). Both for the MVA with and without glare there was a significant group difference (P < 0.05; two-factor analysis of covariance with repeated measurements). CONCLUSIONS: After implantation of diffractive multifocal IOLs of the presently used type (3M 825X), the mesopic vision--both with and without glare--is even more reduced than after monofocal IOL implantation. These findings are particularly relevant for aged pseudophakic car drivers, especially for driving at night.

Dark Adaptation↗
PubMed1994

[Use of the Ellmann Surgitron in eyelid and plastic surgery].

BACKGROUND: The Ellman Surgitron is a new electrosurgical device with high frequencies (4 MHz) for special use in oculoplastic surgery. Four different operational functions are available: (1) cutting with minimal coagulation, (2) combined cutting and coagulation, (3) coagulation and (4) fulguration. METHODS: The Ellman Surgitron was used in plastic eyelid surgery (blepharoplasty of the upper lid) and in resection of tumors of the upper and lower lid. Histological sections of the excised tumours and skin were performed with special respect to the cut tissues. RESULTS: Blepharoplasty in the cutting mode was performed in nearly complete haemostasis. Histological sections of the excised skin documented better perpendicularity of the cut tissues after electrosurgery than after conventional surgery. Superficial or complete resection of small and larger tumours was performed in haemostasis of deep and superficial vessels. Perfect evaluation of histological sections of the cut tissue was possible after dissection in the cutting mode or the combined cutting and coagulation mode. Per primam postoperative wound healing was observed in all subjects. CONCLUSION: Use of the Ellman Surgitron decreases operating time and permits efficient tissue dissection, excellent haemostasis and perfect wound healing in oculoplastic surgery.

Basal Cell Carcinoma↗
PubMed1993

[Asymmetric multizone lenses--a new concept in multifocal intraocular lenses].

BACKGROUND: Asymmetrical multifocal lenses (MIOLs) represent a new concept for binocular implantation of MIOLs: one asymmetrical IOL--destined for implantation in the dominant eye--is favouring distance vision by assuring that 60-70% of the light rays coming from an object will pass through the distance part of the optic. The other IOL--destined for implantation in the second eye--is favouring near vision, enabling that 60-70% of the light energy will be focused by the near zone(s) of the IOL. METHODS: Modulation transfer function (MTF), Strehl-Ratio (SR) and resolution efficiency (RE) were determined in both foci by in vitro measurement. Defocus curves were performed after clinical implantation as well as after "optical implantation" by means of an optical device developed by Reiner. RESULTS: In vitro measurements showed superior results of SR and RE in the favoured focus of the MIOL. Defocus curves after clinical and "optical" implantation yielded higher peaks for visual acuity and contrast in the favoured focus. CONCLUSION: First theoretical and clinical results do confirm the new concept of asymmetrical multifocal IOLs.

Contrast Sensitivity↗
PubMed1993

[Multifocal intraocular lenses--an assessment of current status].

UNLABELLED: Besides the diffractive multifocals, which produce a second focus for near vision by means of diffraction rings, there are different refractive multifocal IOL types with 2-7 refractive zones or an aspheric/spherical construction principle. Long-term results: 2 years after implantation of diffractive multifocal IOLs, the corrected distance and near acuities were unchanged compared to the 3-month results. The uncorrected distance acuity was, however, slightly decreased due to a minus shift of refraction to -1.2 D. The contrast sensitivity was improved after 2 years. Multi- versus monofocal IOLs: After diffractive multifocal IOL implantation, the near acuity with distance correction only was markedly improved compared to monofocal IOLs. All other acuity data did not differ between multi- or monofocal lenses. The contrast sensitivity (at low contrasts and high spatial frequencies) and mesopic visual acuity (without and with glare) were reduced compared to monofocal pseudophakic eyes. Near aniseikonia and binocular functions: In unilateral multifocal pseudophakia (monofocal IOL in fellow eye), a near aniseikonia up to 8% was found. The width of fusion was significantly lower than in bilateral multifocal pseudophakia, whereas the stereopsis showed no difference. Determinants of bifocal function: In 7.1% of our cases, no bifocal function (BFF) was present after implantation of diffractive multifocal IOLs. These patients exhibited a significantly higher age as well as higher pre- and postoperative astigmatism, when compared to patients with good BFF. Optical performance of different multifocal IOLs: By means of an optical system, described by Reiner, images of intraocular lenses can be projected into the eye ("optical implantation"); thus, the optical performance of IOLs can be judged subjectively. Using this method, the refractive 2- and 3-zone models performed best within the multifocal group (contrast sensitivity not significantly worse than that of monofocal IOL), when viewing a low-contrast chart (Regan 4%). All other multifocal lenses (diffractive, aspheric/spherical, refractive 5- and 7-zone models) were significantly inferior to the monofocal IOL. CONCLUSIONS: Implantation of multifocal IOLs should presently be restricted to special indications, particularly to the distinct patient request to dispense with wearing near or bifocal glasses, if possible. Because of the reduction in contrast sensitivity and mesopic vision and the increased glare sensibility, multifocal IOLs should not be implanted especially in professional car drivers. There are, however, differences in optical performance between the various multifocal IOL types. Further improvements, in particular concerning lens technology, will presumably extend the present spectrum of indications.

Contrast Sensitivity↗
PubMed1993

[The Array multifocal lens--functional principle and clinical results].

BACKGROUND: Common refractive bifocal IOLs feature 2 or 3 spherical zones with different refraction; the design of the Array multifocal IOL consists of 5 concentric zones, each of them providing a progressive near addition with multiple foci by means of an aspherical surface. METHODS: As a part of a prospective study, distance and near visual acuity, contrast sensitivity, glare and depth of field were examined in 15 patients with the Array lens and a monofocal control group 12 months after implantation. Subjective assessment of the optical quality was performed by detailed asking for optical symptoms. Results were retrospectively compared with the one year follow-up of 15 patients with diffractive bifocal IOLs. RESULTS: No difference was found for best corrected far and near visual acuity and sensitivity for high contrasts. Glare and sensitivity for low contrasts of the monofocal IOL was significantly superior to both multifocal models. Array IOL and diffractive IOL achieved a near acuity of Nieden 2-1 with only distance correction; defocus curves revealed an increase in the depth of field, but with a superiority of the Array lens in intermediate imaging. Optical symptoms as halos were much more frequent in patients with the diffractive IOL than in the Array group. CONCLUSIONS: Functional results of the Array multifocal IOL seem to be comparable to those of the diffractive bifocal IOL, but with the advantage of an improved intermediate imaging and a reduction of optical side effects.

Aged↗
PubMed1993

["Physical eyes" for evaluating various intraocular lenses for monocular and binocular use].

We developed a "physical eye system" to evaluate visual impression after physical implantation of monofocal and multifocal intraocular lenses (IOLs). The system is constructed as two identical astronomical telescopes. The objectives imitate the cornea and behind this cornea the IOL is inserted. The image quality represents exactly the quality of the intraocular lens.

Equipment Design↗
PubMed1993

[Modulation transfer function and contrast sensitivity of refractive multi-zone multi-focal lenses].

Contrast imaging of new multifocal intraocular lens (MIOL) designs with 5 and 7 refractive zones was examined by in vitro measurement of the modulation transfer function (MTF) and by testing contrast sensitivity with Regan 96% and 11% contrast sensitivity charts after "optical implantation" of MIOLs in 20 healthy subjects by means of a new optical device developed by Reiner. The results were compared with those obtained with a monofocal IOL and a diffractive MIOL. We found that the MTF of both refractive MIOLs showed a reduction in contrast at corresponding spatial frequencies compared with the monofocal and with the diffractive IOL, resulting in a Strehl ratio of below 30%. Contrast sensitivity after "optical implantation" was significantly reduced for the refractive 5- and 7-zone models in high contrast (Regan 96%), but for all MIOL models in low contrast (Regan 11%) compared with the monofocal IOL. The refractive 5-zone MIOL and diffractive MIOL showed no statistical difference in contrast sensitivity.

Contrast Sensitivity↗
PubMed1993

[2 years results of implantation of diffractive multifocal intraocular lenses].

In an ongoing prospective study, we investigated 52 eyes of 40 patients 2 years (range: 22-26 months) after implantation of a diffractive multifocal intraocular lens (3M, type 815LE). The distance visual acuity averaged 0.48 without correction and 0.83 with best correction. The mean refraction (spherical equivalent) amounted to -1.2 D (compared to only -0.32 D 3 months postoperatively). The corrected distance acuity was > or = 1.0 in 40% and > or = 0.5 in 100% of the eyes. A near visual acuity of Nieden 1-3 was achieved in 70.3% without correction, in 75% with distance correction only, and in 100% with additional near addition. Compared to our results 3 months after multifocal lens implantation, the uncorrected distance acuity decreased and the uncorrected near acuity increased 2 years postoperatively both phenomena being attributable to the postoperative minus-shift in refraction. The other acuity values were unchanged in comparison with the 3-month results. Measured with the Ginsburg test, contrast sensitivity at low and medium spatial frequencies improved significantly compared to the 3-month results. An improvement in contrast sensitivity since the early postoperative phase was also found using the Pelli Robson contrast sensitivity chart and--in tendency--using the Regan contrast charts. Hypothetically, these findings may be traced back to a retinal or central nervous cybernetic adaptation mechanism to the implanted multifocal optic.

Aged↗
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

[Endocrine stress response in cataract operations with local anesthesia].

This study was undertaken to investigate the endocrine stress response during cataract surgery in local anaesthesia (LA) with or without additional sedation with midazolam (Dormicum). 20 patients for cataract surgery in LA were randomly allocated to the midazolam-group (before injection of LA, sedation with single doses of 1 mg midazolam until the patient was sleeping, but awakeable), and to the control-group without sedation. Premedication and LA were standardized. The investigation was performed at 7 measuring points starting at the arrival in the preparation room up to 30 min after surgery. Adrenaline in plasma was significantly lower in the midazolam-group. Intraoperatively, adrenaline increased in the control-group and decreased in the midazolam-group. In time course, noradrenaline in plasma decreased in the midazolam-group, in contrast to the control-group. With respect to ADH, ACTH and cortisol, no significant differences were found in group levels or time course, and concentrations remained within normal range. In contrast to the control-group, mean arterial pressure decreased in the midazolam-group during the course of time. There were no differences in heart rate or arterial oxygen saturation between the two groups. Local anaesthesia and premedication were sufficient to prevent psychic and surgical stressors. The slight sympathoadrenergic response in the control-group was significantly reduced by small doses of midazolam. Thus, a careful supplementation of local anaesthesia with midazolam appears advantageous for patients with cardiovascular disorders.

Adrenocorticotropic Hormone↗
PubMed1992

[Evaluation of the image quality of bi- and multifocal intraocular lenses with a new optical system].

By means of a new optical device developed by Reiner, an "optical implantation" of 6 different bi- and multifocal intraocular lenses (MIOLs) was performed in 20 young healthy subjects, and results were compared with those of a monofocal reference IOL. The following parameters were investigated: distance and near visual acuity, depth of focus and contrast sensitivity. The median of distance visual acuity was 1.0 in all IOLs with the exception of a 7-zone refractive MIOL (0.75). Near acuity without near addition was 1.0 in all MIOL models; through focus curves of all MIOLs showed an increase in depth of focus with a typical two peak course. Contrast sensitivity at high contrasts was reduced for the 7-zone-model, but contrast sensitivity at low contrasts was significantly reduced for all MIOLs, except the 2- and 3-zone refractive models.

Adult↗