R Trau

University of Antwerp, Antwerpen, Flanders, Belgium

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Publications (14)2.73 Total impact

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    ABSTRACT: To analyze the performances of the Inpro-Gauss Excimer laser in the treatment of hyperopia and combined hypermetropia-presbyopia. The hypermetropic treatment consisted in making 12 confluent ablation spots of 3.3+/-0.1 mm at 4.5 mm from the corneal apex. The surgical parameters were simulated by a computer model of the corneal profile. The combined hypermetropic-presbyopic treatment was achieved by adding 4 spots of +2 D in the infero-nasal quadrant. Our series included forty eyes of which eleven were treated for hyperopia only and twenty nine were treated both for hyperopia and presbyopia. The uncorrected postoperative visual acuity was equivalent or better than the preoperative corrected visual acuity in 82% of cases. The averaged postoperative spherical equivalent was -0.2+/-0.5 D. Near uncorrected visual acuity was one line better (in decimal notation) for the group treated for both hyperopia and presbyopia than in the single hyperopia group. Surface laser treatment of hyperopia and presbyopia with a gaussian broad beam laser is safe, accurate and reproducible.
    Bulletin de la Société belge d'ophtalmologie 02/2008;
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    ABSTRACT: To evaluate the effect of refractive surgery on binocular vision and ocular alignment in patients with manifest or intermittent strabismus, with or without vertical component. University Hospital Antwerp, Edegem, Belgium. Patients and methods: 13 patients (22 eyes) with strabismus underwent refractive surgery. Five of these patients presented with an esotropia and four of them with a small vertical deviation. Five patients had a manifest exotropia, of whom two presented with a small vertical deviation. Two patients had an intermittent exotropia with binocular vision, of whom one patient had a vertical deviation. One patient had a hypertropia with a dissociated vertical deviation. Ocular alignment and binocular function remained unchanged postoperatively in all except two patients with high anisometropia who experienced an improvement in binocular function. In these patients, the preoperative manifest deviation became intermittent or latent after surgery, allowing fusion and stereopsis. Vertical deviation was found preoperatively in 8 of the 13 patients. This vertical deviation remained unchanged postoperatively, but improved in one patient with anisometropia. Preoperative intermittent or manifest strabismus is not a contraindication for refractive surgery provided some specific recommendations are taken into account, such as an adequate preoperative orthoptic examination and aiming at emmetropia for both eyes.
    British Journal of Ophthalmology 12/2006; 90(11):1410-3. · 2.73 Impact Factor
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    ABSTRACT: To evaluate the mid-term (1-3 years) results of the Gaussian broad-beam excimer laser Delivery System (DS) after single treatment for the correction of myopia. To study the corneal surface with scanning electron microscopy (SEM) after excimer laser ablation using a flying spot delivery system (Bausch & Lomb) and a Gaussian Delivery System (GDS) (InPro). The 1035 consecutive eyes studied were split in four groups with respect to the treated myopia, expressed in spherical equivalent: low myopia up to -3.00 D (183 eyes), moderate myopia from -3.25 D to -6.00 D (540 eyes), high myopia from -6.25 D to -10.00 D (210 eyes) and very high myopia from -10.25 D to -20.00 D (102 eyes). Four post-mortem eyes of two donors were treated using the flying spot DS on one eye and the GDS on the other eye. We achieved postoperative spheriqual equivalent within +/- 1 D of emmetropia in respectively 99.1%, 98.9%, 83% and 21% of the eyes of group 1, 2, 3 and 4. UCVA was 10/10 or better in respectively 65%, 51% and 19% of group 1, 2 and 3. UCVA was 5/10 or better in respectively 86% and 75% of group 3 and 4. The defocus equivalent refraction was 1.0 or less in respectively 98%, 93%, 62%, and 7% of the four groups. On SEM, the corneal surface presented a smooth and polished profile for the GDS. The Gaussian Delivery System gives comparable results to the flying spot laser system for surface laser ablation in myopic eyes up to -10 D. Advantages of this system are: smooth ablation surface, short treatment time, low haze rate, high reliability and easy maintenance of the device due to the optical DS. It is an interesting alternative for the more complex mechanical DS.
    Bulletin de la Société belge d'ophtalmologie 02/2005;
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    ABSTRACT: To study the efficacy of Laser In Situ Keratomileusis (LASIK) and Arcuate Keratotomy (AK) for the treatment of anisometropia and/or astigmatism after Penetrating Keratoplasty (PKP) in an attempt to optimize binocular vision. Correction of post-PKP anisometropia and/or astigmatism was considered only when stable refraction was achieved for at least 6 months. Four eyes were treated for anisometropia and astigmatism using the LASIK technique (IN-PRO Gauss Excimer Laser and SKBM Microkeratome). Five eyes were treated with AK to correct post-PKP astigmatism only. The results were evaluated using the following parameters: uncorrected visual acuity (UCVA), best subjective spectacle correction (BSC-VA), corneal uniformity (CU) index and predictive corneal (PC) acuity from the Holladay Diagnostic Summary (HDS) analysis. Post-PKP anisometropia and astigmatism were treated successfully after primary LASIK in three out of the four cases. One eye needed an additional diode thermal keratoplasty (DTK). Astigmatism post-PKP was treated successfully after primary AK in four of the five cases. One eye needed an additional LASIK. AK can be used successfully in cases of low-grade post-PKP astigmatism. LASIK gives better results in cases of post-PKP anisometropia and astigmatism. In order to affine the final results a combination with other refractive techniques such as DTK can be proposed. CU index and PC acuity (EyeSys-HDS analysis) are poor predictive parameters for visual outcome in cases of irregular corneal surfaces as it is often the case after PKP.
    Bulletin de la Société belge d'ophtalmologie 02/2004;
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    ABSTRACT: To evaluate the efficacy and safety of laser-assisted subepithelial keratectomy (LASEK) for the treatment of myopia and astigmatism (low, moderate and high). Laser-assisted subepithelial keratectomy was performed by 3 surgeons in 45 eyes using an INPRO Gauss Excimer laser (31 eyes) or a NIDEK EC-5000 Excimer Laser (14 eyes). The mean follow-up is 9 months (3-15 months). Preoperative best-corrected visual acuity (BCVA) and corneal topography were measured. The postoperative parameters were: uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical equivalent refraction (SER), defocus equivalent refraction (DER), and corneal topography. The mean preoperative sphere and cylinder were -4.09 diopters (D) +/- 1.94 D (range -1.25 D to -9.75 D) and -0.67 D +/- 0.55 D (range 0 D to -2.50 D) respectively. No eye lost 2 or more lines of BCVA. The UCVA was > or = to 20/20 in 56% of the cases and 20/40 or better in 100% of the cases. No eye developed corneal haze that affected visual acuity. No major complications were recorded. LASEK treatment is a safe and effective technique for treatment of low to high myopia. This surgical technique is less invasive and more effective than LASIK because of the lack of flap- and microkeratome-related complications.
    Bulletin de la Société belge d'ophtalmologie 01/2003;
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    ABSTRACT: To analyse retrospectively the pre- and postoperative refraction and visual acuity according to Standard Graphs proposed by Waring for refractive surgery. Ninety-three eyes with myopia ranging from -1.50 to -8 diopters (D) and/or with astigmatism ranging from 0.75 to 3 D were treated between July 1998 and June 2001. The laser delivers a broad beam with a regular gaussian energy repartition obtained by means of a plate containing an array of diffractive micro-lenses. The coefficient of linear correlation between the attempted and achieved spherical equivalent refraction was 0.97. A postoperative spherical equivalent refraction between -0.50 and +0.50 D was found in 92.3% of eyes. The defocus equivalent refraction (spherical refraction added to one-half of the cylindrical component, ignoring the sign) represents more accurately the reality of the refractive state, and in our study was within +/- 0.50 D for 86.4% of the eyes. A preoperative best corrected visual acuity of 10/10 was found in 78% of eyes and 64% achieved postoperatively an uncorrected visual acuity of 10/10. The InPro-Gauss excimer laser gives good refractive results. The Gauss profile delivery system provides reliability and quality of the ablated surface of cornea.
    Bulletin de la Société belge d'ophtalmologie 02/2002;
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    ABSTRACT: We present a new technique, scanning laser retinoscopy, to spatially resolve in two dimensions the optical aberrations and refractive power of the ocular media. For this purpose, the Maxwellian view of a confocal scanning laser ophthalmoscope (SLO) is configured to scan simultaneously the posterior and the anterior segment of the eye at different levels of prefocussing. This set-up allows retinal imaging and psychophysics through different optical zones of the cornea and lens. In addition, the size of the anatomical pupil can be dynamically controlled by adjusting the colinear infrared and visible light intensities of the illuminating system. In retinoscopic images we can see a part of the retina superimposed by distinctive patterns of shadows in the pupillary area. The variable patterns of shadows in the retinoscopic images change with the level of prefocussing of the SLO. The patterns are the result of local variations in refraction or wavefront aberrations within the lens and cornea. In cases of excimer laser refractive surgery, for example, scanning laser retinoscopy is able to distinguish between a treated central area, transition zone and peripheral cornea. As a corollary, we can document differences between excimer laser delivery systems and also correlate the retinoscopic images with the subjective complaints of refractive surgery patients. These include monocular diplopia, glare, loss of contrast sensitivity besides reduced visual acuity.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
    12/1997;
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    ABSTRACT: The results of two year follow-up after Holmium LTK are presented. The choice of the technique was justified based on experimental, technical and anatomo-pathological data as well as on the property of the corneal collagen fibers to shrink at a temperature of 60-70 degrees C. Although the immediate results were encouraging, we found an important regression after two years follow-up, resulting in a final correction of maximally 1.5 D, independent on the degree of hypermetropia to be treated. These results were obtained with the "contact" method, which is in our experience slightly superior to the "non-contact" technique. The question is whether the regression will continue with time or will stabilize and remain at 1.5 D of hyperopic correction.
    Bulletin de la Société belge d'ophtalmologie 01/1997; 266:75-83.
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    ABSTRACT: We present a new technique, scanning laser retinoscopy, to spatially resolve in two dimensions the optical aberrations and refractive power of the ocular media. For this purpose, the Maxwellian view of a confocal scanning laser ophthalmoscope (SLO) is configured to scan simultaneously the posterior and the anterior segment of the eye at different levels of prefocussing. This set-up allows retinal imaging and psychophysics through different optical zones of the cornea and lens. In addition, the size of the anatomical pupil can be dynamically controlled by adjusting the colinear infrared and visible light intensities of the illuminating system. In retinoscopic images we can see a part of the retina superimposed by distinctive patterns of shadows in the pupillary area. The variable patterns of shadows in the retinoscopic images change with the level of prefocussing of the SLO. The patterns are the result of local variations in refraction or wavefront aberrations within the lens and cornea. In cases of excimer laser refractive surgery, for example, scanning laser retinoscopy is able to distinguish between a treated central area, transition zone and peripheral cornea. As a corollary, we can document differences between excimer laser delivery systems and also correlate the retinoscopic images with the subjective complaints of refractive surgery patients. These include monocular diplopia, glare, loss of contrast sensitivity besides reduced visual acuity.
    Proc SPIE 01/1997;
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    ABSTRACT: The need of medical treatment after photorefractive surgery has been studied by reviewing the literature on the subject and comparing their conclusions with our clinical experience. Considering the pre-operative and immediate post-operative medical treatment, there is a large consensus since the aim is treatment of pain and prevention of superinfection. The post-operative considerations for medical treatment are more controversial and can be considered as to be useful or possibly useful.
    Bulletin de la Société belge d'ophtalmologie 01/1997; 266:113-9.
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    ABSTRACT: Treatment of peripheral post-mortem human corneas with the Holmium laser in a ring pattern resulted in opaque spots. One pair of treated eyes was immediately processed for light and electron microscopy and three other treated eyes were preserved for 4 days in medium in order to compare direct and short-term effects of the Holmium laser. Cross as well as frontal light microscopical sections of all eyes revealed interconnecting bands between the spots. At the ultrastructural level the anterior corneal tissue within these spots was characterized by coagulation of cells and collagen and shoed either a dramatic distorting effect on the epithelium in the eyes processed immediately or a single layer of flattened multi-nucleolated epithelial cells having more than one nucleolus per nucleus in the eyes stored in medium. Furthermore, the spots showed disturbed Bowman's layer, destroyed keratocytes and collagen fibrils which were either coagulated or organized chaotically. The interconnecting bands contained alternating normal and coagulated collagen fibers. The rest of the cornea outside the spots had a normal appearance. In corneas stored in medium, both keratocytes and epithelial cells over the entire cornea exhibited accumulations of cytoplasmic fibrils and glycogen particles. These phenomena were not observed in non-preserved corneas, suggesting that the differences are due to preservation and not due to the laser treatment. It is concluded that morphological changes occur mainly in the treated peripheral cornea whereas the central untreated cornea remains unaffected,indicating that the Holmium laser is a reliable instrument to treat hypermetropic patients.
    Proc SPIE 12/1996;
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    ABSTRACT: The aim of this study was to evaluate the implication of the mechanical factor 'decentration' on the visual outcome after PRK. 100 eyes of 70 patients were included. The mean decentration was 0.27 mm +/- 0.18. Decentration was less than 0.5 mm in 84 percent of the cases. The importance of the decentration was investigated by the statistical correlation of decentration from the pupilcenter and the visual outcome. We did not find any statistical significant association for decentrations less than 1 mm. Our conclusion is that decentration, if less than 1 mm, does not play an important role in the final visual outcome after PRK.
    Proc SPIE 12/1996;
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    ABSTRACT: Until recently, surgical correction of hyperopia was subject to nearly total regression regardless of the method used. Laser thermokeratoplasty (LTK) with the holmium:YAG laser (Sunrise Technologies' Corneal Shaping System) is able to correct hyperopia in the range of + 1.0 to + 3.0 diopters. Up to eight spots with a spot size of 650 micrometers can be delivered simultaneously. According to the amount of hyperopia to be corrected, eight or sixteen spots are administered with respective pattern diameters of six or six and seven mm. The energy density used is 8.5 J/cm2 per spot. Most of the regression occurs within the first month. In the 30 eyes with a follow-up of 6 months patient satisfaction rate is high and complications are minimal.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
    01/1995;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Until recently, surgical correction of hyperopia was subject to nearly total regression regardless of the method used. Laser thermokeratoplasty (LTK) with the holmium:YAG laser (Sunrise Technologies' Corneal Shaping System) is able to correct hyperopia in the range of + 1.0 to + 3.0 diopters. Up to eight spots with a spot size of 650 micrometers can be delivered simultaneously. According to the amount of hyperopia to be corrected, eight or sixteen spots are administered with respective pattern diameters of six or six and seven mm. The energy density used is 8.5 J/cm2 per spot. Most of the regression occurs within the first month. In the 30 eyes with a follow-up of 6 months patient satisfaction rate is high and complications are minimal.
    Proc SPIE 01/1995;

Publication Stats

23 Citations
2.73 Total Impact Points

Institutions

  • 1997–2006
    • University of Antwerp
      • Faculty of Medicine
      Antwerpen, Flanders, Belgium
  • 2002
    • Universitair Ziekenhuis Antwerpen
      Antwerpen, Flanders, Belgium