Biomedical subjects

R Menapace

Publications and source records attributed to R Menapace.

At least 73 records · Page 4Linked to original sources

PubMed1995

Long-term results of combined trabeculectomy and small incision cataract surgery.

We did a prospective study of 49 eyes (36 patients) with coexisting cataract and glaucoma who had combined trabeculectomy, phacoemulsification, and implantation of a folded polyHema intraocular lens through the trabeculectomy opening. Preoperatively, intraocular pressure (IOP) was controlled (< 20 mm Hg) in 13 eyes on a mean of 2.2 medications and uncontrolled (> 20 mm Hg) in 36 eyes on a mean of 2.4 medications. Preoperative visual acuity ranged from 20/40 to hand movements. At the end of the follow-up, IOP was below 18 mm Hg in all eyes (100%), without therapy in 39 (80%) and with reduced therapy in 8 (16%). Two (4%) eyes were controlled on the same medication regimen. Visual acuity improved in 42 patients (86%); 38 (78%) achieved a visual acuity of 20/40 or better. A filtering bleb was observed in 45 eyes (92%). The most common early postoperative complication was fibrin exudation into the anterior chamber. Late complications included posterior synechias and vision-impairing capsule opacifications. Visual acuity improved after neodymium:YAG laser treatment in all eyes with opacification without further complications. We conclude that the combination of small incision cataract surgery and trabeculectomy is a successful surgical approach for long-term visual rehabilitation and glaucoma control.

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PubMed1995

Experience with a suction fixation system for stereotactic radiosurgery of intraocular malignancies.

We designed a suction fixation system for the radiosurgical treatment of intraocular malignancies with the Leksell Gamma Knife. Our device consists of a circular suction chamber and an adjustable unit which is fixed to the Leksell stereotactic head frame. All components are made of plastic in order to avoid artifacts in CT or MRI. A permanent suction of 600-800 mbar is provided by a standard vacuum pump, powered by a portable battery. In the Gamma Knife Unit of the Neurosurgical Department at the University of Vienna, we successfully used this device. Up to April 1994 we successfully performed 25 radiosurgical treatments in 12 patients with large or extra-large uveal melanomas and in 1 patient suffering from a choroidal metastasis.

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PubMed1994

Computerized statistical analysis of corneal topography for the evaluation of changes in corneal shape after surgery.

We examined 20 patients for the effect of a 3-mm sutureless temporal clear corneal incision cataract operation on corneal topography, as recorded with the computer-assisted video-keratoscope TMS-1 (Computed Anatomy, Inc., New York, New York). Each topographic image was cut into 178 fields in eight concentric rings. The refractive values of these fields were stored in a database. The mean differences between the preoperative and one-month postoperative findings were calculated and transformed into color-coded maps as output for the statistical analysis. The patients operated on showed a mean flattening of 0.4 to 1.0 diopter in the temporal region. This was statistically significant by paired Wilcoxon signed-rank tests. There was no significant vertical steepening or nasal flattening, except in two isolated fields. For control purposes, we twice examined 20 age-matched volunteers who were not operated on. The paired Wilcoxon tests of this group did not show significant changes. When compared with Cravy's vector analysis, induced topographic change analysis is better at evaluating surgically induced corneal shape changes.

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PubMed1994

The influence of the incision length on the early postoperative intraocular pressure following cataract surgery.

In a prospective study we recorded the early postoperative intraocular pressure of 60 eyes following phacoemulsification and posterior chamber lens implantation. In 30 patients each the implantation either of a folded polyHema intraocular lens through a 3.5 mm incision or of a polymethylmetacrylate intraocular lens through a 7 mm incision was performed. Healon was used in all eyes and thoroughly evacuated from the capsular bag behind the implanted lens and the anterior chamber. For intraoperative miosis 0.5 ml acetylcholine chloride was injected into the anterior chamber after wound closure. Intraocular pressure was measured preoperatively as well as six hours, 18 hours, one week and two months postoperatively without the influence of antiglaucomatous medication. We found no statistically significant change of intraocular pressure at any measurement time in the 3.5 mm group (Student's t-test, p > 0.1). In the 7 mm group only the rise of intraocular pressure at 18 hours was statistically significant (p < 0.05, student's t-test). The comparison of the changes of intraocular pressure from preoperative values between both groups revealed a statistically significant difference at 18 hours (p < 0.05, student's t-test) but not at any other time recorded. Intraocular pressure exceeding 22 mmHg was found at 6 hours in 4 (13.3%) patients of both groups and at 18 hours in 3 (10%) eyes of the 3.5 mm group and 5 (16%) eyes of the 7 mm group (p > 0.1, Fisher's Exact Test). From these results we conclude that 1) regardless of the wound size the pressure rising effect of Healon is successfully counteracted by the aspiration technique described, and 2) with small-incision cataract surgery statistically significant less changes of intraocular pressure are observed in the early postoperative period.

Acetylcholine↗

PubMed1994

Clinical results with three different kinds of small optic PMMA-IOLs.

In this prospective study the clinical results using three different small optic IOLs are presented. The best results were achieved in those cases with an anterior capsule rim overlapping the entire optic periphery. In those cases with sulcus fixation, haptic in/out and optic in/out positions a higher percentage of capsule fibrosis (Soemmering's rings) was documented (sulcus fixation: 100%, haptic in/out position: 75%, optic in/out position: 65.5%, bag: 7.3%). The fibrosis developed because of contact between the anterior and the posterior capsule leaf. These cases also showed decentrations of the intraocular lens (IOL) more often (sulcus fixation: 50%, haptic in/out position: 75%, optic in/out position: 34.5%, bag: 31.7%). Only one patient was disturbed by glare and halo phenomenons. Cellular reactions on the lens surface were moderate in most cases. Differences specific to lens type were found between the three IOLs implanted. The clinical results were comparable to the results of other comprehensive IOL studies. Under certain indication small optic IOLs represent an alternative to flexible implants for small incision surgery.

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PubMed1994

Evaluation of 100 consecutive IOGEL 1003 foldable bag-style lenses implanted through a self-sealing tunnel incision.

The IOGEL 1003 hydrogel lens, designed for better capsular bag fit, was implanted in 100 consecutive eyes. We evaluated the visual and morphological results obtained with a mean follow-up of six months. Visual acuity was within Food and Drug Administration standards; however, morphological results were less satisfactory. Decentration of 1 mm or more occurred in 24% of the cases. Higher diopter lenses required a minimum incision size of 4 mm and tended to tear when folded. Once in the eye, they regularly came in contact with the iris. A gap between the posterior optic surface and capsule occurred in 61% of eyes. Within the short follow-up period, 9% of eyes required YAG discission because of Elschnig pearl formation. In conclusion, the newer IOGEL 1003 lens performed no better than earlier IOGEL lens models when placed in the bag, and the possible benefit of decreasing posterior lens subluxation after early YAG capsulotomy is offset by the disadvantages.

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PubMed1994

No-stitch, small incision cataract surgery with flexible intraocular lens implantation.

Small incision cataract surgery has several advantages over conventional surgery, including faster postoperative visual rehabilitation. We evaluated 100 consecutive cases of no-stitch, small incision surgery with a square sclerocorneal tunnel and a flexible intraocular lens. Permanent self-sealing of the wound seemed to increase intraoperative safety considerably. With the specific incision used, corneal trauma and irrigation fluid outflow were minimal. Refraction and K-readings stabilized within the first postoperative week, which is when most eyes attained best final visual acuity. No early peak or protracted drift of astigmatism occurred. Minimally leaking wounds in three eyes were left unsutured; a transient filtering bleb was observed in two of these eyes after resorption of an intracameral air bubble. Our results support the theoretical concept and justify the use of no-stitch, small incision surgery.

Cataract Extraction↗

PubMed1994

Evaluation of the first 100 consecutive PhacoFlex silicone lenses implanted in the bag through a self-sealing tunnel incision using the Prodigy inserter.

We evaluated the performance of the PhacoFlex silicone lens with open polypropylene loops and the disposable Prodigy inserter in a series of 100 consecutive no-stitch cases. Loading the lens into the PRO-1A inserter model was easy, as was inserting it through a 4 x 4 mm self-sealing sclerocorneal tunnel incision. If the chamber was deep and the capsular fornix expanded, unfolding the polypropylene loops was safe and direct bag placement was always possible. If the capsular bag was insufficiently distended, however, the posterior loop tended to entangle with wrinkles in the posterior capsule, jeopardizing the capsule's integrity. With a round and well-centered 4 mm to 5 mm capsulorhexis, centration was good provided the lens was completely within the bag. Even with proper bag placement of the haptics, however, the optic occasionally decentered slightly and tilted because of secondary capture in the capsulorhexis opening. With an incomplete capsulorhexis or a jagged-edged capsulotomy, malpositioning was not uncommon. This was due to secondary displacement of one haptic into the sulcus or partial capture of the optic by the anterior capsule leaf. Because of the flexibility of the polypropylene loops, the lenses tended to decenter and tilt following capsular shrinkage.

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PubMed1994

Endocapsular hematoma with biconvex posterior chamber intraocular lenses.

We describe ten cases of endocapsular hematoma that developed in the early postoperative period after cataract or combined glaucoma and cataract surgery. After capsulorhexis and phacoemulsification, one of three types of posterior chamber lenses with biconvex optics was implanted in nine eyes. In one eye, a convex-plano poly(methyl methacrylate) lens was implanted. All lenses were implanted in the bag. Postoperatively, an anterior chamber hyphema was observed in four eyes and erythrocytes in another five. Subsequently observed endocapsular hematomas disappeared gradually over the next several months. A narrow space was visible between the posterior optic surface and the posterior chamber in all eyes with a biconvex lens. We believe that blood from the hematoma seeped behind the anterior capsular leaf into that space. A YAG capsulotomy was not necessary in any case.

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PubMed1994

In vivo documentation of cellular reactions on lens surfaces for assessing the biocompatibility of different intraocular implants.

This prospective study was undertaken to assess the biocompatibility of different intraocular implants and to determine factors influencing cellular reactions on intraocular lenses (IOLs). Cellular reactions seen on the surface of 653 IOLs have been documented by specular microscopy. Various types of IOLs were used with different surgical procedures in humans. The 11 lens types used fall into five groups of materials: polymethylmethacrylate (PMMA), heparin surface-modified PMMA, surface-modified PMMA, poly Hema and silicone. Factors influencing the cellular reaction on intraocular implants were elaborated on in this study. Besides the foreign-body reaction itself, cellular reactions were influenced by an increased inflammatory disposition, surgical trauma, peri-operative treatment, implant positioning and lens style. A significant correlation was found between the development of posterior synechiae and the existence of giant cells on the anterior lens surface. The incidence of cellular reactions on IOLs revealed significant differences specific to lens and material. Hydrophilic surfaces show cellular reactions in a lower percentage of cases compared with hydrophobic surfaces. An accurate and individual selection of lens material and style is mandatory to guarantee optimal after surgery.

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PubMed1994

[Suitability of the open loop lens Phacoflex XI-30 for capsular sick implantation by self-sealing sclerocorneal tunnel incisions].

SCOPE OF THE STUDY: We studied a new intraocular lens implant with a high-refractive silicone optic and prolene C-loops. Suitability for folding and implantation with the recommended instruments as well as its performance as a capsular bag implant were evaluated. The impact of the self-sealing wound construction used on postoperative corneal stability was also studied. PATIENTS AND METHODS: We included 35 consecutively operated eyes. Capsulorhexis and phacoemulsification were performed. A well-centered and round 4-5 mm anterior capsular opening was aimed at. Using the Fine Universal or the Livernois-McDonald folder the optic was folded lengthwise and the leading loop tucked within the crease. The lens was implanted through a self-sealing sclerocorneal tunnel which measured 3.0 mm in length and 3.2 mm in width. RESULTS: With the instrumentation described, a 3.2 mm incision was adequate. - The lens centered well. In one case each decentration resulted from an optic-edge-by-rhexis-rim capture with an inappropriately shaped rhexis and from excessive capsular bag shrinkage with a too small rhexis. As a rule, the posterior capsule was distended and, with five exceptions, firmly attached to the optic. Fibrosis had resulted in only two cases where the rhexis had evaded the optic edge. Except for a single case where a filtering procedure had been simultaneously performed, optic-to-iris clearance was pronounced in all cases. Consequently, signs of iris chafing were never seen and iridocapsular synechiae had never formed in the latter. - Typically, fine granules scattered within the material and a bluish-violet tint were noted. However, neither intensive haze nor brownish discoloration as well as shell- or inner contour-phenomena were never present. - Vector analysis showed a negligible initial astigmatic shift against the wound that did not progress further on. CONCLUSION: This new implant performs very satisfactory. It may be even further improved by eliminating the granular inclusions and increasing the haptic rigidity. In order to prevent fibrotic opacification of the posterior capsule full circular overlap of the optic periphery by the anterior capsular leaf should be aimed at. The advantage of the reduced incision width required for insertion makes it very appropriate for clear corneal incision surgery.

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PubMed1994

Suction attachment for stereotactic radiosurgery of intraocular malignancies.

We designed a suction attachment for the radiosurgical treatment of intraocular malignancies with the Leksell gamma unit (Gamma Knife). Our device consists of a circular suction chamber and an adjustable unit to be fixed to the Leksell stereotactic head frame. All components are made of plastic materials in order to avoid artifacts in CT or MRT imaging. A permanent suction of 600-800 mbar is provided by a standard vacuum pump, powered by a portable battery. Suction times up to 40 min were well tolerated in all cases. We successfully used this device, performing 17 radiosurgical treatments in 8 patients with large or extra-large uveal melanomas and one patient suffering from a choroidal metastasis.

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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.

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PubMed1993

Evaluation of a one-piece poly(methyl methacrylate) intraocular lens with a 7 mm biconvex optic and a total diameter of 10 mm.

To find out how large the total diameter of an open-loop intraocular lens (IOL) should be, we studied 90 consecutive implantations of a one-piece poly(methyl methacrylate) IOL with a 7 mm biconvex optic and a total diameter of 10 mm (Adatomed 75 ST). The lens design made implantation simple, even through a small capsulorhexis. In 85% of the cases, the IOL remained well centered. One case with asymmetric placement of the IOL showed a decentration of more than 1 mm. In 14% of the eyes slight decentrations occurred because the capsular bag was too large. Contact between the iris and IOL was found in 15%. In 4% there were folds in the posterior capsule, and in 35% there was a small space between the IOL and the posterior capsule because the capsular bag was too large. Although the ST lens has a small total diameter, it remained at a distance from the iris in most cases. In-the-bag implantation through a continuous central capsulorhexis is mandatory to avoid secondary displacement; nevertheless, slight decentrations cannot be excluded. For a large capsular bag, the total diameter of an IOL should exceed 10 mm. Clinical results, cellular reaction on the lens surface (26.6%), biocompatibility, and visual performance are comparable to those of other well-approved poly(methyl methacrylate) IOLs.

Adult↗

PubMed1993

Exchange of IOGEL hydrogel one-piece foldable intraocular lens for bag-fixated J-loop poly(methyl methacrylate) intraocular lens.

In 1990, IOGEL lenses placed in the capsular bag were reported to displace into the vitreous after neodymium:YAG (Nd:YAG) laser capsulotomy. We exchanged a bag-placed IOGEL lens in one patient after erroneous biometry and capsular opacification. The technique and results of lens explantation, aspiration of Elschnig pearls, and in-the-bag implantation of a modified J-loop poly(methyl methacrylate) (PMMA) lens are demonstrated. Removal of the soft and nonadhesive IOGEL lens was easy. The capsule pockets held patent by the flanges of the taco-style IOGEL lens allowed for easy insertion and bag fixation of the J-style loops. Visual acuity improved from 20/60 to 20/20. Centration of the exchange IOL was satisfactory. In a series of 61 Nd:YAG laser posterior capsulotomies, we did not observe the reported tendency of IOGEL lenses to luxate posteriorly. Therefore, we recommend Nd:YAG discission of the posterior capsule as the preferred approach to posterior capsule opacification with IOGEL lenses. However, the technical ease of the technique makes the explantation and replacement of IOGEL lenses by a bag-fixated PMMA IOL a valid option to correct an erroneous biometry.

Cataract Extraction↗

PubMed1993

Temporary keratoprosthesis for transscleral fixation of posterior chamber intraocular lenses with penetrating keratoplasty.

In the absence of zonular and capsular support, cataract surgeons increasingly prefer suture-fixated posterior chamber intraocular lenses (IOLs) to angle-supported anterior chamber lenses as a secondary IOL. Various suturing techniques have been proposed for fixating the posterior chamber IOL. Transscleral suture fixation appears advantageous but problematic when performed on an open globe. Moreover, excision of the vitreous base is impeded by the iris and the dark, unstable image. This article describes a technique that takes advantage of a temporary keratoprosthesis (TKP). When sutured onto the trephination opening, the TKP provides a bright, stable image and permits peripheral indentation of the globe, allowing for controlled, thorough vitrectomy. With the infusion pressure supplying adequate eye tone, ab externo transfixation, and thus a targeted passage of the sulcus, is possible. If the cornea permits transfixation, TKP may be used to tamponade after trephination and as a lens rest while the surgeon ties the sutures to the haptics.

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PubMed1993

Long-term results and biocompatibility of heparin-surface-modified intraocular lenses.

A prospective in vivo study of 50 intraocular lenses was done to document the long-term results and biocompatibility of heparin-surface-modified poly(methyl methacrylate) posterior chamber lenses. Continuous curvilinear capsulorhexis and phacoemulsification were performed throughout and examinations were by slit-lamp and specular microscopy. Decentrations of more than 1 mm were seen in 4% of eyes. Stress folds from the haptic traction forces were detected in 16%. A posterior capsulotomy was performed in 10% because of fibrosis or Elschnig pearl formation. Fine fibers were found on the lens surface in 76%. During the first postoperative days only a moderate number of fibroblast-like cells was observed. Foreign-body giant cells were seen in 8%. All cases with foreign-body giant cells had posterior synechias. Visual performance and clinical results were comparable to those of other well-approved intraocular lenses. The low percentage of cellular reaction on the lens surface suggests good biocompatibility.

Adult↗

PubMed1993

[Experiences with disc lenses composed of silicone].

Our study presents the results with a silicone disc-lens (Adatomed 90D) over a postoperative period of 18 months. It includes 47 patients, 42 could be reexamined. The implantation was done after continuous circular capsulorhexis and phacoemulsification with a Faulkner-folder directly into the capsular bag. The implantation was sometimes difficult. Skill and experience of the surgeon are required. The IOL springs forth of the implantation forceps, which can lead to traumatization of the capsule and the iris. Three times the posterior capsule ruptured, in two cases the implantation was stopped because of vitreous pressure and the risk of rupturing the capsule. In 6 cases the rim of the anterior capsule ruptured during the implantation. Postoperatively one IOL had a sulcus position, all other IOLs were in the capsular bag. A deposit of viscoelastic substance (Healon) between the IOL and the posterior capsule in 34 cases (72%) was remarkable. In 14 cases (33%) it remained for 18 months. 16 times (38%) regeneratory after-cataract reached the central part of the capsule. The visual disturbance was different, in 6 cases (14%) a YAG-laser-capsulotomy was performed. An influence of the deposit of viscoelastic substance on the development of posterior capsule opacification could not be proved. 17 IOLs (40%) were minimally decentrated upwards. Only 11 cases (26%) had an excellent mydriatic pupillary reaction. The reason is not clear. 10 eyes (24%) developed iridocapsular synechia, 22 eyes (52%) foreign body giant cells and 20 eyes (48%) dispersed pigment on the IOL surface. The giant cells did not diminish.(ABSTRACT TRUNCATED AT 250 WORDS)

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