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Biomedical subjects

W Hunold

Publications and source records attributed to W Hunold.

At least 19 recordsLinked to original sources
PubMed1995

[No-stitch tunnel incision vs. corneoscleral incision. A prospective, randomized study].

An important factor in early visual recovery after cataract surgery is surgically induced astigmatism. In a randomized clinical trial we compared the development of astigmatism and visual acuity after three different types of incision and suture techniques. Sixty-seven patients were randomized into three groups: (a) scleral tunnel incision (5 mm) without suture (no stitch) (n = 23) (b) scleral tunnel incision (5 mm) with suture (single stitch) (n = 23) (c) corneoscleral incision (5 mm) with suture (CS suture) (n = 21). Implants: 5 mm optic size; follow-up period: 6 months. There was no statistically significant difference among the 3 groups concerning age distribution and preoperative astigmatism. Postoperative follow-up at day 1, weeks 1, 2, months 1, 4 and 6 showed astigmatic values ranging from 0.84 to 1.41 D (means values, vector analysis; differences not significant: P > 0.10). The surgically induced astigmatism ranged from 1.13-1.74 D (differences not significant P > 0.16). At all follow-up dates the mean uncorrected distance acuity did not differ significantly among the three groups (P > 0.35). No quantitative statistically significant differences could be detected among the three incision and suture techniques.

Aged↗
PubMed1994

[Area of contact of the artificial lens and posterior capsule. Systematic study of various haptic parameters].

New techniques in cataract surgery, namely the small and tunnel incisions, have led to intraocular lens (IOL) designs with haptics angulated anteriorly as low as 0 degrees. Clinical and animal studies strongly support the inhibitory influence of contact between the optic and the posterior capsule on the formation of posterior capsular opacification. Human cadaver eyes were used to examine the effect of different haptic angulations (1 degree, 5 degrees, 10 degrees, 15 degrees), different haptic diameters (11.5 mm, 12.0 mm, 12.5 mm), and different optic diameters (5.0 mm, 6.0 mm) on the area of contact between optic and posterior capsule. Exciting fluorescein with a Wood light visualized the space between the IOL and the posterior capsule. Only IOLs with haptics bent forward at more than 10 degrees could achieve contact between IOL and posterior capsule. The haptic and optic diameters had only a limited effect.

Humans↗
PubMed1994

[Night driving capacity of pseudophakic patients].

One hundred pseudophakic patients (aged 62.1 +/- 10.8 years) were examined for glare sensitivity and contrast vision, using the Mesoptometer II, 15.8 +/- 9.8 months after implantation of monofocal intraocular lenses. The patients were tested in order to determine whether they met the requirements of the German Ophthalmological Society (DOG) for the granting of a driver's license. The patients were divided into three groups: (1) pseudophakic bilaterally (n = 50), (2) pseudophakic in one eye with phakic contralateral eye (n = 25), and (3) pseudophakic in one eye with cataract in contralateral eye (n = 25). There were no differences between the groups in corrected distance acuity (ANOVA, P = 0.17). Fifty-two percent of the patients did not fulfill the requirements of the DOG (group 1 50%, group 2 24%, group 3 84%). In groups 1 and 2 the binocular results for glare sensitivity and contrast vision were significantly better than the monocular results (P < 0.001). In group 3, however, there was no difference between binocular and monocular results (P > 0.3). In 20% of patients in this group the binocular results were worse than the monocular results. Results for both contrast vision and glare sensitivity were significantly related to age. Overall, this population of pseudophakic patients were 40-50% less suited to night driving than were healthy volunteers with normal eyes.

Aged↗
PubMed1993

Depth of focus and functional results in patients with multifocal intraocular lenses: a long-term follow-up.

We did a follow-up study of 35 patients who had phacoemulsification with implantation of diffractive, multifocal intraocular lenses (IOLs) 2.5 years ago. The patients had an average age of 58.2 +/- 9.6 years. Fifty multifocal IOLs were implanted (3M 815LE, n = 45; 3M 825X, n = 5). Refractive values, visual acuity, depth of focus, and the dependence on corrective glasses were evaluated. Eighty percent of the spherical equivalents ranged from -1 to +1 D (mean 0.25 +/- 0.71). In 76% the cylindric power was not higher than 1 D (mean 0.87 +/- 0.64). With distance correction, 100% of the patients achieved a visual acuity of 20/40 or better. Without correction, 86% achieved 20/40 or better. Near acuity of 20/40 or better with only distance correction was achieved in 98% of patients. Ninety-four percent had a near acuity of 20/40 or better without any correction. The depth of focus was significantly better in the multifocal group than in a control group of patients with monofocal IOLs (P < .01). Although 90% of the patients had good uncorrected visual acuity results of 20/40 or better for near and distance, 58% preferred glasses for distance and/or near.

Accommodation, Ocular↗
PubMed1993

[Pseudo-accommodation of diffractive multifocal lenses and monofocal lenses].

35 patients were examined for their pseudoaccommodation 6 to 18 months after cataract extraction and implantation of a diffractive multifocal intraocular lens (MIOL). While in 15 patients a MIOL had been implanted in both eyes 20 patients had a MIOL in one eye only. 45 type 3M 815 LE and 5 3M 825 XE lenses were implanted. The mean age was 58.2 years +/- 9.6 years (33 to 76). Only patients without any pathology except cataract and preoperative refractive errors < +/- 5 diopters of spherical and +/- 1 diopter of astigmatic refraction were eligible for implantation of MIOLs. After estimation of the objective and subjective refraction the patients' pseudoaccommodation was measured by testing their visual acuity, adding lenses of +/- 1, 2, 3, 4, 5 diopters to their best distance correction. All patients with MIOLs reached a visual acuity of 0.4 or better with a maximum peak at 0 and -3 diopters. The visual acuity of the MIOL patients was significantly better in the range of -1 to -4 diopters compared to the results of a control group of patients with monofocal IOLs. This suggests a wider range of pseudoaccommodation in patients with MIOLs.

Accommodation, Ocular↗
PubMed1993

[Long-term results of contrast perception and glare sensitivity in patients with diffraction multifocal lenses].

OBJECTIVE: To test the longterm findings for glare and contrast sensitivity in patients with diffractive multifocal intraocular lenses. STUDY DESIGN: Measurements were done using the Mesoptometer II under standardized contrast level and brightness illumination settings (0.032 and 0.1 cd/m2 brightness illumination for testing contrast sensitivity (0.1 cd/m2 brightness illumination and glare of 0.35 Lux for glare testing). Furthermore the patients were tested on their ability to fulfill the requirements of the German Ophthalmological Society (DOG) for mesopic vision to obtain a driver's license. PATIENTS: 40 patients with multifocal intraocular lenses (MIOL), aged 59.3 +/- 9.1 years, were examined 2 years after lens implantation (3M 815 LE and 3M 825 XE) and compared to results of a control-group of 40 patients with monofocal IOL's. RESULTS: There were no significant differences testing contrast sensitivity. Patients with monofocals, however, reached significant better results than patients with multifocals (p < 0.01) when tested for visual acuity under low contrast conditions and glare sensitivity. CONCLUSIONS: Seventy percent of MIOL-patients and 56% of Monofocal-patients failed to meet the minimum requirements for driver's license. Both patient groups showed decreased values for glare and contrast sensitivity when tested 2 years after cataract surgery.

Adaptation, Ocular↗
PubMed1992

Cycloplegic refraction in children: single-dose-atropinization versus three-day-atropinization.

A new scheme for refractive measurements under atropine cycloplegia was tested in 90 strabismic children aged two to several years. Refraction was determined by an autorefractor (CANON R 10) 90 minutes after application of two drops of atropine (0.5% atropine children < 2 1/2 years; 1.0% atropine children > 2 1/2 years) and compared with the results after 3 days of receiving 1 atropine eyedrop 3 times daily. In 86.5% the spherical equivalents differ not more than 1.0 diopter (p = 0.05); the correlation was 0.99. Astigmatic corrections were in agreement in 95.5%, the axis of cylinders in 93.0% (p = 0.05); the correlations were 0.95 and 0.97. The residual accommodation 90 minutes after 2 drops of atropine was not more than 1 diopter in all children. The additional cycloplegic effect of the three-day-atropinization was only 0.5 diopters. This new type of application allows a more rapid and less toxic assessment of refraction than the usual three-day-atropinization.

Accommodation, Ocular↗
PubMed1991

[Refraction by atrophine cycloplegia].

A new method for refractive measurements with atropine cycloplegia was tested in 90 children with squint. Measurements were taken by an autorefractor (Canon R 10) 90 min after application of 2 atropine eye drops and after 3 days of receiving 1 atropine eye drop 3 times daily, i.e. 9 drops per eye. Results were also compared to conventional "objective" refractometry by means of a hand refractometer (Rodenstock PR 50). According to this method, the total refraction, spherical and cylindric power and the cylinder axis are in agreement with refractive data in 80-90% of the children after 3-day atropinization. The additional cycloplegic effect of atropine given for 3 days is only 0.5 dptr compared to the application of 2 drops on the first day. So for practical purposes the refractive data evaluated after 90-min atropinization can be used as a basis for the prescription of glasses.

Atropine↗
PubMed1991

[Lens epithelium necrosis factor for prevention lens opacity].

Posterior capsule opacification is a common postoperative complication after extracapsular cataract extraction and lens implantation. If the patient's visual acuity is reduced markedly, a capsulotomy with a Nd-YAG laser may become necessary. Various attempts have been made with the aim of developing an injectable solution capable of damaging the epithelial cells of the capsule bag irreversibly and thereby avoiding posterior capsule opacification. This solution should be applied for a short time during the operation. In tissue culture we tested the influence of two injectable solutions [lens epithelial necrosis factor (LENF)] and aqua bidest. on cellular growth. Balanced salt solution served as control. We used human epithelial carcinoma cells, type HEp-2. The results were evaluated by vital staining (ethidium bromide and acridin orange), hemotoxylin staining, autoradiography and measurement of protein and DNA synthesis. The results showed that LENF is capable of damaging 100% of the epithelial cells irreversibly if it is applied for 20 s or longer. The influence of each of these solutions was tested on 20 human capsular flaps, which were excised during the operation. The flaps were immersed for 30 s in the different solutions. Vital staining of these flaps led to the following results: LENF causes a 100% cell damage of all epithelial cells of the capsular flaps. No vital cells remained. On the other hand Aqua bidest. cannot guarantee 100% cell damage of the capsular flap epithelia. Sixty percent of the capsular flaps treated with aqua bidest, showed differing amounts of remaining vital cells.

Biological Factors↗
PubMed1991

[Experience with hydrophilic silicone disc intraocular lenses].

When oxygen plasma was used for plasma etching it was possible to hydrophilize the surface of silicone intraocular lenses (IOLs) without changing the chemical composition or the properties of deeper layers of the polymer. The modification was characterized by surface analysis. (Electron spectroscopy = XPS, contact angle estimations) and by scanning electron microscope. A cytotoxic influence of the modified surface could be excluded by cell culture experiments in which we evaluated cell spreading, cell morphology, DNA synthesis and protein synthesis. In vivo experiments on rabbits showed that the postoperative foreign body reaction was not significantly influenced by the hydrophilization of the IOL surface. Over the entire follow-up period (12 weeks), there was a reduced tendency to induce posterior synechiae in the group with hydrophilized lenses (P = 0.009). The number of dislocations and the incidence of posterior opacification did not differ significantly; on the other hand there were indications of improved adhesion to the posterior lens capsule of the hydrophilized IOL.

Animals↗
PubMed1990

[Animal experiment studies of the biocompatibility of colored and plain lens haptics of polymethylmethacrylate].

In spite of the great clinical success of cataract surgery and intraocular lens implantation, adverse reactions still occur. In 2-3% of all cases, there is acute or chronic inflammation. One reason might be that the biocompatibility of the lens material is insufficient. This study evaluates the biocompatibility of dyed and undyed transparent PMMA lens haptics. The haptics were implanted subcutaneously in mobile and immobile mice tissue. After different implantation periods varying from 1 week to 6 months, the haptics were removed and evaluated histologically. The undyed PMMA lens haptics showed no adverse reactions. The dyed PMMA lens haptics showed a strong inflammatory response caused by diffusion of the dye into the surrounding tissue.

Animals↗
PubMed1989

A method to study the interaction between intraocular lens loops and anterior segment vasculature.

Gold-coated plastic casts of the anterior segment ocular microcirculation of the rabbit eye were studied by scanning electron microscopy to define the interaction between ciliary sulcus fixated intraocular lenses and the anterior segment vasculature. A detailed description of the technique is given. Interactions such as loop deformation by the tissue and loop erosion into the vascular tissue are shown. Possible clinical applications of this experimental model are discussed.

Animals↗
PubMed1989

[Corneal endothelial damage in congenital and juvenile glaucoma].

Corneal changes are typical for infantile glaucoma. In newborns, Descemet's membrane and the stroma are still soft, and distend when intraocular pressure rises. Cell counts were performed under the reflecting microscope to determine whether the endothelium is affected when corneal diameter increases and changes occur in Descemet's membrane. The mean endothelial cell density of 20 patients with congenital or secondary juvenile glaucoma, aged between 4 and 29 years, was found to be 2780/mm2. Even though increased corneal diameter was the most common primary symptom of buphthalmos, there were no relationships between corneal diameter on the one hand and postoperative endothelial cell density, visual outcome, or postoperative pressure on the other. In children who had had corneal edema followed by ruptures of Descemet's membrane the number of endothelial cells was significantly reduced, visual outcome was worse, and there were more problems with regulation of intraocular pressure. Lower-than-average endothelial cell densities were also found in some patients with secondary glaucoma.

Adolescent↗
PubMed1988

[Clinical use of the Canon R10 autorefractometer for determining refraction in children with strabismus].

Using a Canon R 10 Autofractor, refraction was measured in 131 children with squint. Measurements before and after cycloplegia were compared to a reference measurement (taken with the Rodenstock PR 50 hand-held refractometer after cycloplegia). In 80% of the cases the power and axis of the cylinder equalled the reference measurements. Due to accommodation, 40% of the values for spherical equivalents before cycloplegia were false. After cycloplegia 80% of the spherical equivalents were also in agreement with the reference measurement. The short examination time and the interesting fixation target facilitate multiple measurements in children. As a result, refraction can be measured more reliably with the R 10 Autorefractor than with the hand-held refractometer in children from age 2 1/2 or 3. Retinoscopy is only indispensable in cases where it is difficult or impossible to use an autorefractor, i.e., on children aged under 2 1/2 and those with extreme head tilt.

Accommodation, Ocular↗
PubMed1987

[Biomicroscopy of an intraocular lens. Comparison of specular microscopy findings with the cytologic specimen].

Seventeen months after implanting an anterior chamber intraocular lens the lens had to be removed because of secondary glaucoma and retinal hemorrhage. The lens had been examined 5 days prior to surgery. It appeared that histiocytic giant cells and fibroblasts had settled on its surface. This was subsequently confirmed by cytological studies. It therefore appears possible to describe an in vivo differential cytology and to diagnose the type of inflammatory reaction in vivo.

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