Biomedical subjects

H Weghaupt

Publications and source records attributed to H Weghaupt.

18 recordsLinked to original sources

PubMed2001

Tritan colour contrast sensitivity function in refractive multifocal intraocular lenses.

AIMS: To compare tritan colour contrast sensitivity (CCS), without and with glare, in patients with refractive multifocal intraocular lenses (IOLs) and with monofocal intraocular lenses. METHODS: Tritan CCS was determined (Moorfields Vision System, CH Electronics) in 15 eyes (14 patients, 75.7 (+/-6.6) years) with a refractive multifocal IOL (Allergan SA 40N) and in 11 eyes (10 patients, 73.7 (+/-6.4) years) with a monofocal IOL (Allergan SI 40 NB). Measurements were made monocularly under mesopic conditions at a distance of 2 metres from the monitor with best distance refraction plus 0.5 D at 0.5, 1, 3, 6, 11.4, and 22.8 cycles per degree (cpd). The test was then repeated for the multifocal IOLs, adding minus 2.5 D to the best distance refraction to force the patient to use the near focus. Both lenses were also investigated under glare conditions with the same set-up and using the brightness acuity tester (BAT). RESULTS: The tritan CCS function without glare in multifocal lenses through the distance focus was nearly identical to that through the near focus. The following statistically significant differences were measured: the CCS function without glare for the multifocal lens was worse at 0.5 cpd and 1.0 cpd than that of the monofocal lens. In CCS testing of the multifocal group with glare at 6 cpd, the results through the distance focus were better than the results through the near focus. For the CCS function with glare, the values for the distance focus in the multifocal lens were worse than the values for the monofocal lens at 0.5 cpd and 1 cpd. In CCS testing with glare through the near focus and CCS testing through the monofocal lens, the monofocal lens performed better at 0.5 cpd, 1 cpd, 3 cpd, and 6 cpd. CONCLUSION: Refractive multifocal intraocular lenses influence tritan CCS function compared to monofocal lenses.

Aged↗

PubMed2001

Halo size under distance and near conditions in refractive multifocal intraocular lenses.

AIMS: To calculate the diameter of halos perceived by patients with multifocal intraocular lenses (IOLs) and to stimulate halos in patients with refractive multifocal IOLs in a clinical experiment. METHODS: Calculations were done to show the diameter of halos in the case of the bifocal intraocular lens. 24 patients with a refractive multifocal IOLs and five patients with a monofocal IOL were asked about their subjective observation of halos and were included in a clinical experiment using a computer program (Glare & Halo, FW Fitzke and C Lohmann, Tomey AG) which simulates a light source of 0.15 square degrees (sq deg) in order to stimulate and measure halos. Halo testing took place monoculary, under mesopic conditions through the distance and the near focus of the multifocal lens and through the focus of the monofocal lens. RESULTS: The halo diameter depends on the pupil diameter, the refractive power of the cornea, and distance focus of the multifocal IOL as well as the additional lens power for the near focus. 23 out of 24 patients with a refractive multifocal IOL described halos at night when looking at a bright light source. Only one patient was disturbed by the appearance of halos. Under test conditions, halos were detected in all patients with a refractive multifocal IOL. The halo area testing through the distance focus was 1.05 sq deg +/- 0.41, through the near focus 1.07 sq deg +/- 0.49 and in the monofocal lens 0.26 sq deg +/- 0.13. CONCLUSIONS: Under high contrast conditions halos can be stimulated in all patients with multifocal intraocular lenses. The halo size using the distance or the near focus is identical.

Aged↗

PubMed1998

Contrast sensitivity and glare disability with diffractive and refractive multifocal intraocular lenses.

PURPOSE: To compare contrast sensitivity and glare disability provided by diffractive and refractive multifocal intraocular lenses (IOLs). SETTING: University Eye Clinic Vienna, Austria. METHOD: This study evaluated the contrast sensitivity and glare disability in 29 eyes with a diffractive multifocal IOL (3M815LE) and 12 with a three-piece, five-zone refractive multifocal IOL (AMO Array SSM 26 NB). The Brightness Acuity Tester (Mentor, Inc.) was used with stationary sinusoidal gratings at spatial frequencies of 0.5, 1, 3, 6, 11.4, and 22.8 cycles per degree (cpd) generated on a television monitor (Nicolet CS 2000). RESULTS: The contrast sensitivity functions of both multifocal IOL groups were within the reference range and were identical at 0.5, 1, and 22.8 cpd spatial frequencies. At 3, 6, and 11.4 cpd, the contrast sensitivity function in the diffractive IOL group was 6, 9, and 10% lower than in the refractive IOL group, and the difference between groups was statistically significant at 6 cpd. When glare was present, contrast sensitivity in the diffractive IOL group was generally in the lower limit of the reference range and remained below at 3 and 6 cpd. Contrast sensitivity in the refractive IOL group remained below the reference range at 3 cpd. At 0.5 and 1 cpd, there were no differences between the groups. At the middle and high spatial frequencies (3, 6, 11.4, 22.8 cpd), contrast sensitivity in the diffractive group was 8, 16, 11, and 12% lower than in the refractive group. At 6 cpd, the between-group difference was statistically significant. CONCLUSION: Diffractive multifocal IOLs provided decreased contrast sensitivity and greater glare disability than refractive multifocal IOLs.

Adult↗

PubMed1998

Comparison of pseudoaccommodation and visual quality between a diffractive and refractive multifocal intraocular lens.

PURPOSE: To determine depth of focus and visual quality after implantation of a diffractive intraocular lens (IOL) and a refractive IOL. SETTING: University Eye Clinic, Vienna, Austria. METHOD: This study comprised 10 eyes of 9 patients with a diffractive IOL (3M 825x + 4) and 13 eyes of 9 patients with a refractive lens (AMO Array SSM 26NB). Depth of focus was evaluated in a defocused range of -6.0 to +3.0 diopters (D), and Snellen visual acuity was recorded. RESULTS: Distance acuity peaked at 1.0 +/- 0.2 (3M group) and 0.91 +/- 0.13 (AMO group). The near acuity peaks were at 0.82 +/- 0.15 and 0.55 +/- 0.14, respectively. Visual acuity of 0.5 was possible in a range of defocus of +1.0 to -4.0 D (3M) and +1.0 to -3.5 D (AMO). CONCLUSION: Pseudoaccommodation and full distance visual acuity were realized with both types of multifocal lenses. For intermediate distances, visual acuity may be limited to activities that do not require optimal vision. At near distances, the 3M lens provided statistically significantly better visual acuity.

Accommodation, Ocular↗

PubMed1998

Corneal flap incision technique for sutureless cataract surgery.

A self-sealing incision technique for cataract surgery has been developed. It is appropriate for implantation of rigid-optic intraocular lenses (IOLs) up to 7.0 mm. The incision is designed to meet the principle criteria of sutureless cataract surgery, such as optimal instrument handling, easy IOL implantation, and minimal postoperative patient care.

Cataract Extraction↗

PubMed1997

[Visual acuity and use of eyeglasses after implantation of a diffractive multifocal lens].

BACKGROUND: The implantation of a diffractive multifocal lens (dMIOL) as alternative to a monofocal lens is justified if after surgery there is practically no need to wear glasses. PATIENTS AND METHODS: 31 patients had an implantation of a total of 35 dMIOLs (3M 815 LE). We evaluated the visual acuity, the refractive data and the patients' attitude to wearing glasses. The average age was 67.0 +/- 11.8 years. Follow up took place after 18.7 +/- 5.4 months. RESULTS: The mean value of the uncorrected distance acuity was 0.59 +/- 0.17 and the corrected distance acuity 0.96 +/- 0.13. The uncorrected near acuity amounted to Jg 2.40 +/- 0.94, best distance correction was Jg 1.49 +/- 0.55. The patients still accepted an average of 0.68 +/- 0.37 dpt for the best near correction (near vision over the diffractive near focus) and thus achieved Jg 1.46 +/- 0.55. At the best distance correction plus 3.5 dpt, the near visual acuity was improved to 1.03 +/- 0.17. 54.8% of the patients indicated that they did not use glasses at all. 32.3% stated that they only used glasses for reading. 9.7% wore bifocals all the time, and 3.2% always used glasses for the distance. CONCLUSIONS: Regarding distance vision, the dMIOL is equivalent to monofocal lenses. Without any correction the results of the dMIOLs for the near vision are superior to monofocal lenses. Glasses can be dispensed with if the uncorrected visual acuity of the operated eye is at least 0.6 Jg 2-3 after surgery and the other eye too, does not need any correction. In case the postoperative visual acuity is worse, good visual acuity of the other eye may render glasses unnecessary. Part of the patients put up with a correctable loss of visual acuity in order not to become dependent on glasses. The need to wear glasses may be decreased considerably by implanting a dMIOL in both eyes and by avoiding postoperative refraction errors.

Adult↗

PubMed1997

[Multifocal intraocular lenses as an alternative in cataract surgery].

The development and introduction of multifocal intraocular lenses (MIOL) should provide the patient with a pseudoaccomodation for distance and near acuity without spectacle corrections. For this study two different types of multifocal lenses have been investigated concerning their visual properties. For diffractive MIOL (3M, type 815LE) an uncorrected distance visual acuity of Snellen 0.59 +/- 0.17 was found. The near visual acuity was J 2.4 +/- 0.94 and Snellen Acuity of 0.5 was achieved in a range of defocus of -1.25 D to +4.0 D. For refractive MIOL (Allergan, type Array SSM 26NB) an uncorrected distance visual acuity of Snellen 0.79 +/- 0.17 was found. The near visual acuity was J 2.75 +/- 1.35 and Snellen Acuity of 0.5 was achieved in a range of defocus of -1.0 D to +3.5 D. With this multifocal lenses the patients reached functional results for distance vision as well as with monofocals. Because of the existing pseudo-accommodation the results for near vision lay over of those of monofocals and the need spectacle correction decrease.

Aged↗

PubMed1996

Topical versus peribulbar anesthesia in clear corneal cataract surgery.

PURPOSE: To evaluate the efficacy of topical anesthesia as an alternative to peribulbar anesthesia in clear corneal cataract surgery. SETTING: Department of Ophthalmology, University of Vienna, Austria. METHODS: In this prospective, double-blind clinical trial, 36 patients had bilateral cataract surgeries performed from 1 to 3 months apart. Half of the patients had topical anesthesia for the first surgery and peribulbar anesthesia for the second surgery. The other half had peribulbar first and then topical. All surgery was done using a temporal clear corneal approach and bimanual phacoemulsification followed by in-the-bag intraocular lens implantation. Subjective pain was assessed using a visual analog scale of no pain (0%) to worst pain imaginable (100%) and intraoperative motility using a rank scale of adverse motility (-5) to ideal patient cooperation (+5). RESULTS: Subjective pain was comparable whether topical or peribulbar anesthesia was used (mean 10.75 versus 10.97%; P > .6). Patient cooperation (motility) was significantly better when topical anesthesia was used (+2.16 versus +1.11; P = .03). There were no significant differences in complications. A peribulbar block was given in addition to the topical anesthesia in two cases. CONCLUSIONS: Topical anesthesia is a safe, effective alternative to peribulbar anesthesia in clear corneal cataract surgery.

Administration, Topical↗

PubMed1996

Visual properties of the foldable Array multifocal intraocular lens.

PURPOSE: To evaluate visual acuity, depth of focus, contrast sensitivity, and glare disability in eyes with an Array SSM 26-NB three-piece, five-zone multifocal intraocular lens (IOL). SETTING: University Eye Clinic, Vienna, Austria. METHOD: Fourteen eyes with an AMO Array IOL were evaluated for uncorrected and best corrected distance and near visual acuity. The reading distance produced by the near focus of the lens was varied with convex glasses of less power. Reading at distance focus was evaluated by adding +3.50 diopters (D) to the distance correction. Depth of focus was measured from -3.00 to +6.00 D. Contrast sensitivity and glare disability were also measured using the Brightness Acuity Tester with stationary sinusoidal gratings at 0.5, 1, 3, 6, 11.4, and 22.8 cycles/degree. RESULTS: Mean uncorrected distance acuity (Snellen) was 0.79 +/- 0.17 (SD), which increased to 0.94 +/- 0.14 with best correction. Near acuity was J2.75 +/- 1.35 and J2.59 +/- 1.10, respectively. When near focus was tested for reading distance, a mean of +0.54 +/- 0.02 D was accepted for improvement of near vision of J1.71 +/- 0.94. Near acuity with a distance focus addition of +3.50 D was J1.08 +/- 0.28. Contrast sensitivity and glare disability were lower than in 13 eyes with a monofocal poly(methyl methacrylate) IOL and 16 normal phakic eyes. CONCLUSIONS: Eyes with the Array IOL had full distance function. Reading performance could be improved with a near focus of more than +3.50 D. Full near vision could be achieved with the distance focus and conventional reading glasses. Depth of focus was sufficient but visual acuity was limited at intermediate and near distance. Although contrast sensitivity was relatively low, it was not beyond the reference range.

Aged↗

PubMed1994

Different techniques of extracapsular cataract extraction: bacterial contamination during surgery. Prospective study on 230 consecutive patients.

This study was performed to investigate the correlation between the contamination of the anterior chamber and the technique of extracapsular cataract extraction (ECCE). Three different methods were used: uncomplicated planned ECCE, phacoemulsification involving suturing method, and sutureless technique. All patients had posterior chamber intraocular lenses implanted. Two hundred and thirty consecutive patients were included in this prospective study, and preoperative smears of the conjunctiva and intraoperative aspirates of the anterior chamber were investigated. Samples of the aqueous humor were taken at the beginning and at the end of the operation. Cultures were incubated and held for 14 days. More than 71% of the preoperative smears were contaminated by coagulase-negative staphylococci, the most commonly isolated bacteria. However, 27% of the patients had culture-positive anterior chamber aspirates intraoperatively, also with coagulase-negative staphylococci as the most frequent organisms. In no case did postoperative endophthalmitis develop. Preliminary results in a small population show that the contamination of the aqueous humor is statistically significantly less frequent if the cataract extraction is performed by phacoemulsification than if it is done without phacoemulsification. Another interesting finding is that anterior chamber contamination is not significantly more frequent, if a sutureless technique is used for cataract surgery.

Adult↗

PubMed1994

[Long-term results of implantation of a plate haptic silicone lens in the capsular sac].

BACKGROUND: An important step in developing cataract surgery was the introduction of soft foldable silicone intraocular lenses in the middle 80's. Functional and morphological long-term data are a vital base for definite conclusions on the new material's safety and biocompatibility. PATIENTS AND METHODS: Our study presents the long-term results after the implantation of a silicone posterior chamber lens with solid plate haptic design (STAAR AA-4203). All lenses were folded and implanted through a 4-mm small corneoscleral incision. Our study includes 54 eyes in 52 patients with a mean follow-up period of 56.5 +/- 8.9 months. RESULTS: A visual acuity of 20/40 or better was found in 90.7% of all eyes. All except one of the 33 eyes without any further preexisting ocular pathology at the time of the operation achieved a visual acuity of 20/40 or better. Two thirds of all eyes had a horizontal astigmatism of +1.0 D or less. By slitlamp examination more or less dispersed pigment was seen on the IOL's surface in 46.3%. 83% of the silicone lenses were centrated within 0.5 mm. A YAG-laser capsulotomy was performed in 7 cases (13%). IOL-related intraocular inflammations, cystoid macular edema or an elevated intraocular pressure did not occur in this group. CONCLUSIONS: Our satisfactory long-term results suggest an excellent biocompatibility of the IOL's design and material.

Aged↗

PubMed1993

Functional vision with hydrogel versus PMMA lens implants.

As a particular test of visual function, contrast sensitivity reveals optical properties of Iogel pHema lenses in comparison to poly(methyl methacrylate) implants (PMMA). Sixteen patients with a hydrogel posterior chamber lens in one eye and a PMMA posterior chamber lens in the other were examined by means of contrast sensitivity measurements. Six stationary, vertical, sinusoidal modulated gratings with spatial frequencies of 0.5, 1, 3, 6, 11.4 and 22.8 cycles/degree were presented. Results of the two different implants were analyzed by a paired t-test. There was no significant statistical difference between the two types of lenses for any of the gratings presented. Despite different features like material, refractive index, design and UV-absorbing additive, there seems to be no difference between lenses made of hydrogel and those made of PMMA material with regard to functional vision as evaluated by contrast sensitivity testing.

Aged↗

PubMed1991

Pattern electroretinogram and luminance electroretinogram in Alzheimer's disease.

Visual symptoms are often among the first complaints of patients suffering from Alzheimer's disease and several studies showed a delay in flash visual evoked potentials. Hinton et al. (1986) described optic nerve degenerations in patients with Alzheimer's disease and Sadun published a dropout of retinal ganglion cells that range from 30% to 60%. The reduction of neurotransmitters, especially of acetylcholine, found in the brain might also occur in the retina. Therefore we examined the retinal functions of patients suffering from Alzheimer's disease. In eight patients the pattern-electroretinograms and the scotopic and photopic luminance-electroretinograms were recorded and compared to an age-matched control group. We could not find any abnormalities in the pattern- and the luminance electroretinograms of patients with Alzheimer's disease. Although cholinergic cells have been found in the retina, our results did not reveal an involvement of retinal functions in Morbus Alzheimer.

Aged↗

PubMed1990

Effect of levodopa on the human luminance electroretinogram.

Scotopic and photopic electroretinograms (ERGs) were recorded in 12 healthy volunteers before and 90 and 180 min after administration of levodopa. After 90 min the drug significantly increased the scotopic ERG b-wave amplitude and implicit time. The dark-adapted oscillatory potentials (OPs) were selectively affected, while no changes were observed in the photopic ERG. Levodopa had no effect on the ERG after 180 min drug applications. As a control, the experimental procedure was repeated without drug administration, and no changes were observed.

Adult↗

PubMed1989

Reversible changes of visual acuity and pattern-electroretinograms after blue-green argon laser photocoagulation of diabetic patients.

Visual acuity, color vision, pattern-visual-evoked-potentials (P-VEPs) and pattern-electroretinograms (P-ERGs) were measured in 13 diabetic subjects before, and 24 hours and 5 weeks after blue-green argon laser treatment. As control, the same examinations were performed in 7 normal subjects and 7 diabetic patients before and after slit lamp examination with the Goldman three mirror contact lens. Visual acuity and P-ERG amplitudes were significantly reduced one day after the laser treatment, while 5 weeks after the laser coagulation, visual acuity and P-ERG amplitudes recovered to pretreatment values. The control group showed no significant changes after slit lamp examination. Since fluorescein angiography revealed no macular changes after laser treatment, the possibility of a reversible functional light damage after blue-green argon laser coagulation (ALC) is discussed.

Aged↗

PubMed1989

Comparison of contrast sensitivity between posterior chamber lenses of silicone and PMMA material.

Seventeen patients received a posterior chamber lens of PMMA in one eye and a silicone lens (Staar Surgical Co.) in the other. Contrast sensitivity was examined in both eyes in order to detect differences with respect to the material used for lens implantation. An attempt was made to exclude any changes in the eyes that were not due to lens implantation and that might possibly have an influence on the result. A paired T-test was performed for each spatial frequency. No statistically significant difference was found between the two materials with regard to contrast sensitivity.

Aged↗

PubMed1989

Effect of levodopa on the human pattern electroretinogram and pattern visual evoked potentials.

Pattern electroretinograms (P-ERGs) and pattern visual evoked potentials (P-VEPs) were recorded at three luminance levels and five different check sizes in a group of 16 control subjects before and after the oral administration of levodopa. At the lower luminance levels, significant decrease in P-ERG and P-VEP latencies were found. For P-VEPs the latency changes occurred only at small check sizes. No changes were observed in control experiments without levodopa administration. Our results show that levodopa-induced changes even occur at the retinal level and support a dopaminergic involvement in light and dark adaptation. Our observations are in agreement with a VEP delay found in Parkinson's disease and with a VEP latency increase in rats after dopamine depletion.

Administration, Oral↗

PubMedDate not supplied

Long-term course of induced astigmatism after clear corneal incision cataract surgery.

PURPOSE: To determine whether a small clear corneal temporal incision produces less surgically induced astigmatism than a larger incision. METHODS: One hundred three consecutive cases of postoperative astigmatism after clear corneal incision cataract surgery were studied for a minimum of 1 year. Only self-sealing incisions from the temporal side were made as follows: 3.2 mm (Group A); 4.0 mm (Group B); 5.2 mm (Group C). We considered the amount and axes of the keratometric readings at different times as well as their course over time. Induced astigmatism was calculated using three methods. Axial changes were also analyzed. RESULTS: Immediately after the surgery, there was a small, surgically induced, with-the-rule astigmatic shift in all groups, which in most cases decreased to near preoperative levels with time. One year postoperatively. mean induced astigmatism was 0.09 diopter (D) in Group A, 0.26 D in Group B, and 0.54 D in Group C. Most cases had minimal axial changes. In Group A, 86% had an axial change of fewer than 30 degrees; in Group B, 76%; and Group C, 73%. CONCLUSIONS: The smallest incision group had the least surgically induced astigmatism and axial change. All incision groups remained stable and had satisfactory clinical results.

Astigmatism↗