Publications by authors named "Loay Daas"

40 Publications

Descemet Membrane Endothelial Keratoplasty (DMEK) in Previously Vitrectomized Eyes: Complications and Clinical Outcomes.

Klin Monbl Augenheilkd 2021 Jul 26. Epub 2021 Jul 26.

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg, Germany.

Purpose: To evaluate the results and complications of Descemet membrane endothelial keratoplasty (DMEK) in previously vitrectomized eyes.

Design: Retrospective study of 35 eyes that had undergone DMEK, due to Fuchs endothelial corneal dystrophy (FECD), at our department with a follow-up after 6 months postoperatively. We compared the intraoperative procedure, complications, and results of DMEK between 14 previously vitrectomized pseudophakic eyes (group 1) and a control group of 21 pseudophakic non-vitrectomized eyes (group 2).

Results: The unfolding time (in minutes) was significantly longer in group 1 than in group 2 (10.5 ± 6.4 vs. 3.2 ± 1.5, p < 0.01). A single re-bubbling was needed in 8 patients in group 1 (57.1%) and in 3 patients in group 2 (14.2%) (p < 0.01). Repeated re-bubbling (≥ 1 time) was performed in only 5 patients of group 1 (35.7%). There was significant postoperative improvement in best-corrected visual acuity (BCVA, in LogMAR) in both groups (p = 0.04 in group 1 and p < 0.01 in group 2). The central corneal thickness (CCT, in µm) did not differ significantly between the two groups preoperatively (p = 0.4) or postoperatively (p = 0.1). However, the CCT decreased significantly postoperatively in both groups (p < 0.01 in both groups). The postoperative endothelial cell density (ECD in cell/mm²) was significantly lower in group 1 than in group 2 (p = 0.03).

Conclusion: DMEK in previously vitrectomized eyes presents a surgical challenge, which requires special, and sometimes unpredictable, intraoperative maneuvers, but good functional and morphological results can be achieved. The use of the endothelial Descemet membrane lamellae (EDML) of older donors might be recommended to facilitate the intraoperative unfolding process.
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http://dx.doi.org/10.1055/a-1517-4518DOI Listing
July 2021

Semiquantitative Criteria in the Eye Bank That Correlate with Cornea Guttata in Donor Corneas.

Klin Monbl Augenheilkd 2021 Jun 22;238(6):680-687. Epub 2021 Jun 22.

Department of Ophthalmology, Saarland University Hospital and Saarland University Faculty of Medicine, Homburg, Germany.

Background: Cornea guttata may not be recognized in the eye bank and recent studies have displayed that guttae are transplanted in about 15% of cases in varying severities. The purpose of this study was to establish semiquantitative criteria for the detection of cornea guttata in donor corneas in the eye bank.

Methods: In this retrospective cohort study, preoperative endothelial pictures of donor corneas were collected and classified according to the post-penetrating keratoplasty cornea guttata grade into three distinct groups: group 1 consists of healthy corneas with no guttae (guttata grade 0); group 2 constitutes corneas with mild asymptomatic cornea guttata (guttata grade +); and group 3 comprises corneas with advanced widespread cornea guttata (guttata grade ++/+++/++++). The preoperative pictures of each group were then individually analyzed using the following five semiquantitative criteria: The number and the area of the cell-depleted surfaces, the presence of less than 50% of the cells having a hexagonal or a circular shape, the presence of cell membrane defects and interruptions, the presence of blebs in the cell membrane, and the presence of groups of cells with a distinct whitish color.

Results: In total, 262 patients were included in this study, with a total number of 1582 preoperative donor corneal endothelial pictures. Out of those pictures, groups 1, 2, and 3 encompassed 995 (62.9%), 411 (26.0%), and 176 (11.1%) pictures, respectively. Three out of the five eye bank criteria were found to correlate with postoperative cornea guttata with a highly significant p value of < 0.001. These three criteria are the presence of less than 50% of the cells having a hexagonal or a circular shape, the presence of cell membrane defects and interruptions and, the presence of blebs. The presence of groups of cells with a distinct whitish color was only a weak predictive factor for cornea guttata (p = 0.069). There was no statistically significant correlation between the number and the area of cell-depleted surfaces and postoperative cornea guttata with a p = 0.181.

Conclusion: Three semiquantitative criteria that can be detected in the eye bank using inverted light microscopy seem to correlate with postoperative cornea guttata: The presence of blebs, the presence of cell membrane defects and interruptions, as well as endothelial pictures with less than 50% of the cells having a hexagonal of circular shape. The presence of groups of cells with a distinct whitish color appears to be a weak predictor of cornea guttata.
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http://dx.doi.org/10.1055/a-1498-1846DOI Listing
June 2021

[Central Sclerocorneoplasty à Chaud in Bacterial Superinfected Mycotic Keratitis Confirmed by Confocal Microscopy at the Base of Recurrent Herpetic Keratitis].

Klin Monbl Augenheilkd 2021 May 17. Epub 2021 May 17.

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes, Homburg (Saar), Deutschland.

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http://dx.doi.org/10.1055/a-1386-5229DOI Listing
May 2021

Clinical Comparison of the Performance of Two Marketed Ophthalmic Viscoelastic Devices (OVDs): The Bacterially Derived Healon PRO OVD and Animal-Derived Healon OVD.

J Ophthalmol 2020 18;2020:8874850. Epub 2020 Nov 18.

Department of Ophthalmology, Saarland University Medical Center UKS, Homburg, Saar, Germany.

This clinical investigation compared the clinical performance of two marketed ophthalmic viscoelastic devices (OVDs): the bacterially derived Healon PRO OVD (test) and the animal-derived Healon OVD (control) under normal use conditions during cataract removal and lens implantation. This prospective, multicenter, randomized, parallel, participant/evaluator masked, postmarket investigation enrolled 139 subjects (170 eyes), 116 (143 eyes) of which were treated (73 test; 70 control group). Both test and control OVDs were used, at a minimum, to inflate the anterior chamber and protect the endothelium prior to cataract extraction according to the standard procedure. The surgeon completed a postsurgery OVD clinical performance questionnaire, and intraocular pressure (IOP) was measured before surgery and at the 1 day postoperative visit with Goldmann applanation tonometry. Any IOP measurement of 30 mmHg or higher was considered a "spike" and recorded as a study-specific, serious adverse event. The bacterially derived Healon PRO OVD was found to be statistically noninferior to the overall clinical performance of the animal-derived Healon OVD control; thus, the primary hypothesis was satisfied. There were no statistically significant differences between OVD groups for any of the additional endpoints relating to IOP changes or to safety, thus satisfying additional hypotheses. The Healon PRO OVD showed statistically significant improvements in surgeon ratings for ease of injectability, transparency/visibility, and ease of IOL placement. The safety profile was also similar between OVD groups with regards to serious and/or device-related adverse events, as well as medical and lens findings. The results of this clinical investigation support the safety and effectiveness of the bacterially derived, currently marketed Healon PRO OVD and indicate that the intraocular surgical performance was similar between the two OVDs.
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http://dx.doi.org/10.1155/2020/8874850DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8028729PMC
November 2020

Large-Diameter Penetrating Keratoplasties are Mostly Due to Very Severe Infectious Keratitis and Cannot Always Prevent Secondary Enucleation.

Klin Monbl Augenheilkd 2021 Apr 14. Epub 2021 Apr 14.

Augenheilkunde, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Homburg (Saar), Germany.

Purpose: To report the indications and outcomes of penetrating keratoplasties with a graft diameter > 8.5 mm in severe corneal diseases at the Department of Ophthalmology at Saarland University Medical Centre.

Study Design: Retrospective (6 years), descriptive, and observational.

Methods: Thirty-five large-diameter penetrating keratoplasties (LDPKPs) in 27 patients (mean age, 62 ± 22 years) were performed from March 2010 to December 2016. The indication for surgery, number of previous corneal transplantations, best-corrected visual acuity (BCVA) before surgery, intraocular pressure, graft status, and BCVA at last follow-up were recorded.

Results: Infectious keratitis represented 83% of the indications (of those, 45% fungal). The mean corneal graft diameter was 10.8 ± 1.7 (min 8.75, max 15.0) mm. Twenty-three eyes (65% absolute) had at least one previous penetrating keratoplasty (mean graft size, 9.2 ± 1.6 mm). The mean pre-surgery BCVA was 1.96 ± 0.23 logMAR. With a mean follow-up period of 20.2 ± 13.4 months, the mean BCVA was 1.57 ± 0.57 logMAR at last follow-up. Overall, 12 grafts (35%) remained clear until the last follow-up, and in 23 grafts (65%), the primary disease recurred, or corneal decompensation developed. Up to the last follow-up, 6 eyes (17%) had to be enucleated.

Conclusions: In complex cases of infectious keratitis requiring a LDPKP to remove the complete pathology and preserve eye integrity, the visual outcomes are generally expected to be poor, not only because of the well-known risks of LDPKP but also because of the consequences of the infectious disease itself. This knowledge is important for adequate counselling of the patient preoperatively.
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http://dx.doi.org/10.1055/a-1396-4787DOI Listing
April 2021

Reliability analysis of successive Corneal Visualization Scheimpflug Technology measurements in different keratoconus stages.

Acta Ophthalmol 2021 Mar 22. Epub 2021 Mar 22.

Department of Ophthalmology, Saarland University Medical Center, Homburg, Germany.

Background: This study assesses the reliability of successive corneal biomechanical response measurements by the Corneal Visualization Scheimpflug Technology (CST, Corvis ST , Oculus Optikgeräte, Wetzlar, Germany) in different keratoconus (KC) stages.

Methods: A total of 173 eyes (15 controls: 15 eyes, and 112 KC patients: stages 1|1-2|2|2-3|3|3-4|4, n = 26|16|36|18|31|26|5 according to Topographical KC Classification, TKC) were repeatedly examined five times with the CST, each after repositioning the patient's head and re-adjusting the device. Tomographical analysis (Pentacam HR ; Oculus, Wetzlar, Germany) was performed once before and once after CST measurements. Outcome measures included (1) A1 velocity, (2) deformation amplitude (DA) ratio 2 mm, (3) integrated radius, (4) stiffness parameter A1 and (5) Ambrósio relational thickness to the horizontal profile (ARTh). The Corvis Biomechanical Index (CBI) is reported to be extracted out of these parameters. Mean values of the five measurements and Cronbach's α were calculated as a measure for reliability.

Results: Ambrósio relational thickness to the horizontal profile and SPA1 were significantly higher in controls (534|123) compared to TKC1 (384|88), TKC2 (232|66), TKC3 (152|55) and TKC4 (71|27; p < 0.0001). The other parameters were similar in controls and TKC1 (A1 velocity: 0.148|0.151 m/s; integrated radius: 8.2|8.6 mm ), but significantly higher in TKC stages 2 to 4 (DA ratio 2 mm: 5.5|6.3|8.0; A1 velocity: 0.173|0.174|0.186 m/second; integrated radius: 10.9|12.8|19.0 mm ; p < 0.0001). All parameters proved to be highly reliable (Cronbach's α ≥ 0.834) and the corneal tomography remained unaffected.

Conclusions: The individual parameters included in the CBI (consisting of ARTh, SPA1, DA ratio 2 mm, A1 velocity and integrated radius) are highly reliable but differ KC stage-dependently.
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http://dx.doi.org/10.1111/aos.14857DOI Listing
March 2021

Endothelial Cell Density and Central Corneal Thickness following Penetrating Keratoplasty of Acanthamoeba Keratitis Patients - A Retrospective Cross-Sectional Observational Study.

Klin Monbl Augenheilkd 2021 Mar 17. Epub 2021 Mar 17.

Dr Rolf M. Schwiete Center for Limbal Stem Cell and Congenital Aniridia Research, Saarland University, Homburg/Saar, Germany.

Purpose: To analyze endothelial cell density (ECD) and central corneal thickness (CCT) following penetrating keratoplasty (PKP) in keratitis (AK) patients.

Patients And Methods: In this retrospective, clinical, single-center, cross-sectional, observational study, patients were enrolled who underwent PKP at the Department of Ophthalmology of Saarland University Medical Center, Homburg/Saar, Germany between May 2008 and December 2016 with the diagnosis of AK. In all, 33 eyes of 33 patients (14 males, 42%) were enrolled; their mean age at the time of surgery was 39.5 ± 14.3 years. Postoperatively, AK patients received topical polyhexamethylene biguanide, propamidine isethionate, neomycin sulphate/gramicidin/polymixin B sulfate, and prednisolone acetate eye drops (5 ×/day each), and the topical treatment was tapered sequentially with 1 drop every 6 weeks over 6 months. CCT was recorded using Pentacam HR Scheimpflug tomography and ECD with the EM-3000 specular microscope before surgery and 3 and 6 months after surgery as well as after the first and second (complete) suture removal.

Results: ECD tended to decrease significantly from the time point before surgery (2232 ± 296 cells/mm) to the time point 3 months after surgery (1914 ± 164 cells/mm; p = 0.080) and to the time point after the first suture removal (1886 ± 557 cells/mm; p = 0.066) and decrease significantly to the time point after the second suture removal (1650 ± 446 cells/mm; p = 0.028). CCT did not change significantly over the analyzed time period (p ≥ 0.475).

Conclusion: In AK, endothelial cell loss does not seem to be accelerated following PKP, despite the postoperative use of diamidine and biguanide. A subsequent prospective comparative study should confirm our retrospective longitudinal analysis.
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http://dx.doi.org/10.1055/a-1353-5171DOI Listing
March 2021

[Excimer laser-assisted DALK: a case report from the Homburg Keratoconus Center (HKC)].

Ophthalmologe 2021 Feb 25. Epub 2021 Feb 25.

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrbergerstr. 100, Geb. 22, 66421, Homburg/Saar, Deutschland.

Indications: The aim of excimer laser-assisted deep anterior lamellar keratoplasty (excimer-DALK) is, as in mechanical DALK, the treatment of keratectasia (keratoconus and pellucid marginal degeneration), stromal scars or stromal corneal dystrophy. A prerequisite for surgery is the absence of (pre‑) Descemet's scars and an intact endothelium.

Surgical Technique: After excimer laser-assisted trephination to 80% of the corneal thickness at the trephination site, intrastromal air injection (so-called big bubble) and lamellar corneal preparation, a lamellar anterior transplantation of the endothelium-free donor tissue is performed. The technique combines the advantages of DALK and excimer laser trephination. We describe the steps of an excimer-DALK from the Homburg Keratoconus Center (HKC).

Conclusion: Excimer-DALK is a viable treatment option for patients with intact endothelium. In cases of intraoperative perforation, conversion to excimer-perforating keratoplasty (PKP) with all the advantages of excimer laser trephination remains feasible.
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http://dx.doi.org/10.1007/s00347-021-01342-3DOI Listing
February 2021

[Purpureocillium lilacinum : Atypical pathogen of mycotic keratitis in an immunocompetent patient].

Ophthalmologe 2021 Feb 13. Epub 2021 Feb 13.

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrberger Str. 100, Gebäude 22, 66421, Homburg/Saar, Deutschland.

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http://dx.doi.org/10.1007/s00347-021-01325-4DOI Listing
February 2021

[Descemet Membrane Detachment after Complex Cataract Surgery - DMEK is Not Always Necessary].

Klin Monbl Augenheilkd 2021 02 12;238(2):162-165. Epub 2021 Jan 12.

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes, Homburg (Saar), Deutschland.

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http://dx.doi.org/10.1055/a-1268-9042DOI Listing
February 2021

Thickness and Curvature Changes of Human Corneal Grafts in Dextran-Containing Organ Culture Medium Before Keratoplasty.

Cornea 2021 Jun;40(6):733-740

Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany.

Purpose: To determine the changes of corneal thickness and curvature of human corneal grafts in organ culture medium II, containing dextran T500 6%, before keratoplasty.

Methods: We examined the tomography of 24 corneas from our eye bank transferred from medium I into medium II. Images were repeated hourly during 24 hours using an anterior segment optical coherence tomography. The central corneal thickness (CCT) was measured with the manual measurement tool of the anterior segment optical coherence tomography. The radii of curvature (anterior flat and steep and posterior flat and steep) were measured with a MATLAB self-programmed software for "sterile donor tomography."

Results: The mean CCT (±SD) at baseline (T0) was 727 ± 156 μm. It reached 581 ± 103, 506 ± 84, 472 ± 79, and 456±7 μm after 6, 12, 18, and 24 hours, respectively. After 12 hours, 83% of the final deswelling was achieved. The radii of curvature (±SD) at baseline (T0) were (posterior flat, posterior steep, anterior flat, and anterior steep) 6.6 ± 0.5, 6.2 ± 0.5, 7.7 ± 0.4, and 7.4 ± 0.4 mm, respectively. After 24 hours, the radii of curvature reached 6.8 ± 0.1, 6.6 ± 0.3, 7.6 ± 0.1, and 7.4 ± 0.2 mm, respectively.

Conclusions: The kinetics of the deswelling process in medium II follow a hyperbolic curve. Considering a CCT of 506 μm at T12, we assume that a time interval of 12 hours in medium II might be enough for clinical purposes. This result might help to keep storage in medium II as short as possible to escape potential toxic effects of dextran in medium II. The radius of curvature does not seem to change within 24 hours for all measured surfaces.
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http://dx.doi.org/10.1097/ICO.0000000000002543DOI Listing
June 2021

The Homburg Cross-Stitch Marker for Double-Running Sutures in Penetrating Keratoplasty.

Klin Monbl Augenheilkd 2020 Dec 7. Epub 2020 Dec 7.

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes UKS, Homburg (Saar), Germany.

Introduction: Until now, the double-running cross-stitch according to Hoffmann used in penetrating keratoplasty (PKP) has been routinely carried out by simply using a sense of proportion. As a result, the estimation of the precisely defined entry and exit points of the sutures and, by extension, the success of the running cross-stitch suture was completely dependent on the practical experience of the surgeon. Therefore, we introduced the cross-stitch marker as a supporting instrument for PKP surgery.

Methods: Description of the Homburg cross-stitch marker with an exact step-by-step guide on how the instrument is implemented while performing a PKP to mark entry and exit points for sutures including a video to demonstrate the use of this instrument.

Results: The new Homburg cross-stitch marker ensures the precise localisation of the entry and exit points of the suture. This new instrument allows inexperienced surgeons in particular to feel very confident when performing the running sutures.

Conclusion: Surgeons with little experience can completely avoid using their still imprecise sense of proportion and significantly shorten the learning curve for this procedure.
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http://dx.doi.org/10.1055/a-1275-0807DOI Listing
December 2020

Efficacy, safety, and predictability of transepithelial photorefractive keratectomy: meta-analysis.

J Cataract Refract Surg 2021 May;47(5):634-640

From the Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany (Sabau, Daas, Flockerzi, Seitz); Medical Biometrics, Epidemiology and Health Informatics Institute, Homburg/Saar, Germany (Behkit, Wagenpfeil); Institute of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany (Langenbucher); Department of Ophthalmology, Medical University of Graz, Graz, Austria (Ardjomand).

Purpose: To evaluate the efficacy, safety, and predictability of transepithelial photorefractive keratectomy (TransPRK) for correcting myopia, astigmatism, and hyperopia.

Setting: Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany.

Design: Meta-analysis of retrospective or prospective studies.

Methods: Relevant studies were collected from Medline and included when meeting the following predefined criteria: randomized controlled trials, at least 1 of the main outcome measures as efficacy, safety, or predictability, and 1 common TransPRK laser (Schwind Amaris). The parameters estimates and 95% CI were derived from random-effects meta-analysis to account for possible heterogeneity.

Results: Because hyperopia studies did not meet the inclusion criteria, the results are centered on myopia and astigmatism. Sixteen studies with a total of 1924 treated eyes were included in the meta-analysis. The mean efficacy, safety, and predictability had a probability of 94% (CI, 0.86-0.97), 0% (CI, 0.00-0.03), and 89% (CI, 0.82-0.93), respectively. The mean correction index, difference vector, and index of success had a value of 1.01 (CI, 1.01-1.02), 0.20 (CI, 0.06-0.34), and 0.12 (CI, 0.07-0.18), respectively.

Conclusions: This summary estimate showed that TransPRK was highly effective, safe, and predictable in correcting myopia and/or astigmatism.
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http://dx.doi.org/10.1097/j.jcrs.0000000000000487DOI Listing
May 2021

Tomographically normal partner eye in very asymmetrical corneal ectasia: biomechanical analysis.

J Cataract Refract Surg 2021 03;47(3):366-372

From the Department of Ophthalmology, Saarland University Medical Center UKS (Fraenkel, Hamon, Daas, Flockerzi, Suffo, Seitz), and Institute of Experimental Ophthalmology, Saarland University (Eppig), Homburg/Saar, and AMIPLANT GmbH (Eppig), Schnaittach, Germany.

Purpose: To point out the biomechanical changes of the topographically and tomographically normal partner eye (NPE) in patients with very asymmetrical corneal ectasia.

Setting: Department of Ophthalmology, Saarland University Medical Center in Homburg/Saar, Germany.

Design: Retrospective study.

Methods: The topographical and tomographical results of the NPE were assessed using the Pentacam HR and the biomechanical corneal properties using the Ocular Response Analyzer (keratoconus match index [KMI], corneal hysteresis [CH], and corneal resistance factor [CRF]) and the Corvis ST (topographic biomechanical index [TBI] and Corvis biomechanical index) and compared those results with a normal control group (CG).

Results: The clinical records of 26 patients recruited from the Homburg Keratoconus Center diagnosed with a very asymmetrical corneal ectasia were reviewed. The NPE (8.5 ± 1.5 mm Hg) showed a significantly more pathological CH (P < .001) compared with the CG. The CRF was also significantly more pathological (P = .04) for the NPE (8.3 ± 1.5 mm Hg) compared with the CG. The NPE (0.62 ± 0.32) showed a nonsignificant (P = .08) more pathological KMI compared with the CG. Nineteen (73.1%) of 26 NPE had a KMI less than 0.72 and were considered pathological. Compared with the CG, the TBI of the NPE (0.19 ± 0.25) did not differ significantly overall (P = .57). However, 5 (19.2%) of 26 eyes had a TBI more than 0.29 and were considered pathological.

Conclusions: Topographically and tomographically NPEs in very asymmetrical corneal ectasia frequently showed biomechanical changes. This should be considered before planning any type of refractive corneal surgery in such patients.
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http://dx.doi.org/10.1097/j.jcrs.0000000000000435DOI Listing
March 2021

[A 63-year-old male patient with acute visual deterioration after penetrating keratoplasty for keratoconus].

Ophthalmologe 2021 07 15;118(7):728-731. Epub 2020 Sep 15.

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrberger Str. 100, Gebäude 22, 66421, Homburg/Saar, Deutschland.

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http://dx.doi.org/10.1007/s00347-020-01226-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8260397PMC
July 2021

Reproducibility of Non-Invasive Endothelial Cell Loss Assessment of the Pre-Stripped DMEK Roll After Preparation and Storage.

Am J Ophthalmol 2021 01 11;221:17-26. Epub 2020 Aug 11.

Department of Ophthalmology, Saarland University Medical Center, Homburg, Germany.

Purpose: To present a novel, reproducible, and noninvasive method to quantify endothelial cell loss (ECL) of pre-stripped endothelial Descemet membrane lamellae (EDML) caused by its preparation and storage for 5 days.

Design: Prospective laboratory investigation.

Methods: Thirty EDML were stripped from corneoscleral discs and placed in a well plate containing organ culture medium 1 without dextran. An additional 5 corneoscleral discs were also placed in the same medium and served as a control group. Endothelial cell density (ECD) was measured without any additional manipulation by using spectral microscopy following an extensive protocol by which 3 clear images from the center and periphery were used for each measurement, and each measurement was repeated 5 times. ECD was measured before and directly after preparation and on days 1, 2, and 5 of storage.

Results: The average ECD of the 30 corneoscleral discs, which later underwent stripping, was 2,292 ± 308 cells/mm vs 2,129 ± 222 cells/mm for the 5 corneoscleral discs of the control group. The ECL of the control group was significantly lower than that of the EDML group (P < .0001), reaching ±2% versus 11 ± 5%, respectively, on day 0; 3% ± 4% versus 19 ± 10%, respectively, on day 1; 2% ± 2% versus 22% ± 11%, respectively on day 2; and 4% ± 3% versus 23% ± 9%, respectively, on day 5. Reproducibility of the results on all measurement days was good, with Cronbach alpha values ranging from 0.85 to 0.98.

Conclusions: A highly reproducible, noninvasive method was presented for measuring the ECD of the EDML. Prestripped EDML lose a significant amount of cells, up to 11%, due to the preparation process and up to 23% after 5 days of storage. Therefore, shipping them after several days of storage to be used in a DMEK surgery cannot be recommended.
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http://dx.doi.org/10.1016/j.ajo.2020.08.001DOI Listing
January 2021

Corneae from body donors in anatomy department: valuable use for clinical transplantation and experimental research.

BMC Ophthalmol 2020 Jul 13;20(1):284. Epub 2020 Jul 13.

Department of Ophthalmology, Saarland University Medical Center (UKS), Homburg, Germany.

Background: Explanted corneae are highly needed for the surgical management of patients with severe corneal diseases. The aim of this study was to determine whether the body donors from the Institute of Anatomy are a suitable source of donor corneae.

Methods: At the Institute of Anatomy at Saarland University Medical Center in Homburg, corneae are prelevated from body donors who had consented to the removal of tissues for transplantation purposes during their lifetime. Following the report of death, the LIONS Eye Bank is informed and the contraindications of corneal explantation are clarified. Obtaining a blood sample within 24 h postmortem is mandatory.

Results: The Institute of Anatomy had 150 body donors in the time period from January 2018 to June 2019. Out of these, 68 (45.3%) were reported to the Eye Bank. The age of the donors (median 82 years (range: 57-96)) is not critical since the quality of the corneae depends on the number of endothelial cells (mean: 2109 ± 67 cells/mm (range: 511-2944 cells/mm)). Contraindications were present in 19 (12.6%) cases. The corneae were extracted from 49 (32.7%) body donors. Out of these 98 corneae, 46 (46.9%) were successfully transplanted. Of all non-transplanted corneae, 6 (6.1%) were microbiologically contaminated, 10 (10.2%) had a positive serology, 22 (22.5%) had an endothelial cell count < 2000 cells/mm and 6 (6.1%) are at time of this analysis still in culture medium. The non-transplanted tissues were used for research.

Conclusions: Explanted corneae from the Institute of Anatomy are a valuable option in obtaining grafts for corneal transplantation, which is why we are working toward on expanding cooperation with this department.
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http://dx.doi.org/10.1186/s12886-020-01546-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359266PMC
July 2020

[Descemet membrane endothelial keratoplasty DMEK - Donor and recipient step by step].

Ophthalmologe 2020 Aug;117(8):811-828

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes UKS, 66421, Homburg/Saar, Deutschland.

In 2020 Descemet membrane endothelial keratoplasty (DMEK) has become the gold standard in Germany for the treatment of corneal endothelial diseases; however, the widespread use of DMEK was initially limited due to problems with donor preparation and the difficulty of correctly and gently unfolding the endothelial Descemet membrane (EDM) in the anterior chamber. Following the situational donor selection, the safe single-handed donor preparation of the cornea without tearing or even rupturing the EDM, including the indispensable peripheral semicircular orientation marking. Also presented is a step by step atraumatic loading of the glass cartridge, the introduction of the EDM roll into the anterior chamber, and its safe step by step unfolding based on (1) the sequential use of jets of fluid, (2) repeated tapping on the peripheral/central cornea, (3) controlled flattening of the anterior chamber, (4) use of air bubbles of defined size and finally, the fixation of the EDM in correct orientation to the back of the host cornea with a gas bubble. Since every wrong step with DMEK can have far-reaching consequences for patient and surgeon, this step by step pragmatic approach should minimize the incidence of donor tissue damage and failure in patient maneuvers.
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http://dx.doi.org/10.1007/s00347-020-01134-1DOI Listing
August 2020

[A 27-year-old man with "corneal opacity" after being injured by a branch].

Ophthalmologe 2021 02;118(2):186-189

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrbergerstr. 100, Gebäude 22, 66421, Homburg/Saar, Deutschland.

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http://dx.doi.org/10.1007/s00347-020-01130-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7862528PMC
February 2021

[Chameleon-Like Corneal Disorders: Acanthamoeba Keratitis].

Klin Monbl Augenheilkd 2020 Jun 19;237(6):754-760. Epub 2020 May 19.

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes Homburg/Saar.

Acanthamoeba keratitis is a "chameleon". It presents classically with greyish epithelial changes, perineuritis, superficial multifocal stromal infiltrates and ring infiltrate. In the presence of clinical signs, polymerase chain reaction, in vitro culture or histopathological examination have to be used to confirm the diagnosis. In vivo confocal microscopy is applied as an early non-invasive ad-hoc diagnostic method.
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http://dx.doi.org/10.1055/a-1147-9019DOI Listing
June 2020

Recurrent fungal endophthalmitis after intravitreal injections of bevacizumab.

Am J Ophthalmol Case Rep 2020 Mar 7;17:100591. Epub 2020 Jan 7.

Department of Ophthalmology, Saarland University Medical Center UKS, 66421, Homburg/Saar, Germany.

Purpose: We intend to describe an uncommon case of recurrent post-cataract fungal endophthalmitis after intravitreal injections of Bevacizumab.

Observations: A 73-year-old male, who underwent an uncomplicated cataract surgery 8 months ago, presented to our department with postoperative endophthalmitis 5 days after his fifth intravitreal injection (IVI) of bevacizumab for treatment of cystoid macula edema caused by central retinal venous occlusion 6 months ago. The visual acuity (VA) was 0.1 (20/200). The patient underwent an emergency pars plana vitrectomy. Culture of vitreous tap was negative. Eight weeks later, the patient presented again with recurrent endophthalmitis 2 days after his sixth IVI of bevacizumab. VA was hand motion. The patient was treated with an emergency anterior and posterior segment washout with intracapsular posterior intraocular lens (pIOL) extraction. Culture of pIOL revealed fungi in the capsular bag. Six months later, clinical findings were stable with no signs of intraocular inflammation, VA was 0.3 (20/60).

Conclusions And Importance: we assume that this is a rare case of chronic late-onset post-cataract fungal endophthalmitis, which was activated by repeated intravitreal injections of Bevacizumab.
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http://dx.doi.org/10.1016/j.ajoc.2020.100591DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7206407PMC
March 2020

Structural changes in the corneal subbasal nerve plexus in keratoconus.

Acta Ophthalmol 2020 Dec 10;98(8):e928-e932. Epub 2020 Apr 10.

Department of Ophthalmology, Saarland University Medical Center, Homburg, Germany.

Background: Corneal confocal microscopy (CCM) allows visualizing slightest alterations within the corneal subbasal nerve plexus (SNP). Recent CCM studies based on the analysis of three-five CCM images per eye assumed a reduced corneal nerve fibre length (CNFL) in keratoconus (KC).

Methods: The SNP of KC patients (n = 23, 13 contact lens wearing, 10 noncontact lens wearing) and patients without KC (n = 16) was examined by 10 CCM images of one eye per patient. The CNFL per frame area was calculated, and the SNP tortuosity was quantified by measuring (a) the amplitude of the curves and (b) the area under the curve (AUC) formed by the SNP.

Results: Analysing 390 non-overlapping confocal images revealed the CNFL (mm/mm ) to be significantly lower in KC (16.4 ± 1.9 mm/mm ) than in healthy corneae (23.8 ± 3.3 mm/mm , p < 0.0001; mean ± SD; p-value calculated using the Mann-Whitney U-test), without a difference between contact lens wearing and noncontact lens wearing KC patients (p = 0.4). Amplitudes and AUCs analysed as median with 25th and 75th percentile were significantly increased in KC (amplitude 33/23/41 µm and AUC 2839/1545/3444 µm ) compared to healthy corneae (amplitude 24/18/28 µm and AUC 1870/1193/2327 µm , p < 0.0001).

Conclusions: Corneal confocal microscopy (CCM) visualizes slightest alterations within the SNP in KC including (a) a significantly lower CNFL and (b) an enhanced winding course of the SNP. The significantly lower CNFL observed in KC may support the hypothesis of a neurodegenerative aspect of the disease and might be a measure to be correlated with the severity and progression of the disease.
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http://dx.doi.org/10.1111/aos.14432DOI Listing
December 2020

8.5/8.6-mm Excimer Laser-Assisted Penetrating Keratoplasties in a Tertiary Corneal Subspecialty Referral Center: Indications and Outcomes in 107 Eyes.

Cornea 2020 Jul;39(7):806-811

Department of Ophthalmology, Saarland University Medical Center UKS, Homburg/Saar, Germany.

Purpose: To report the indications and outcomes of 8.5/8.6-mm excimer laser-assisted penetrating keratoplasties (PKPs) at a tertiary corneal subspecialty referral center.

Methods: This retrospective, descriptive, observational study included 107 PKPs performed in 96 patients (mean age, 53 ± 12 years). The patients' indications for surgery, best-corrected visual acuity, surface regularity index, surface asymmetry index, topographic astigmatism, central endothelial cell density, central corneal thickness, and graft status were recorded preoperatively, 6 weeks postoperatively, and before (12 ± 2 months) and after (19 ± 4 months) the suture removal.

Results: The surgeries included 48 primary PKPs and 59 repeat PKPs. The main indications were corneal ectatic disorders (50%), severe corneal keratitis (21%), and corneal scars (16%) in the primary PKP group and highly irregular astigmatism after PKP (51%) and previous graft decompensation (37%) in the repeat PKP group. From preoperative measurements to the last follow-up visit without sutures, we found significant improvements (P < 0.001 for all) in visual acuity (0.7 ± 0.3 LogMAR to 0.3 ± 0.2 LogMAR), surface regularity index (1.5-1.0), and surface asymmetry index (2.59-1.1). At the last follow-up, the mean outcome measurements did not significantly differ between the primary and repeat PKP groups. Overall, 89 grafts (83%) remained clear at the last follow-up.

Conclusions: In cases of ectatic disorders and highly irregular astigmatism after keratoplasty, 8.5/8.6-mm excimer laser-assisted PKP seems to be an excellent treatment option, achieving a significant improvement in visual acuity.
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http://dx.doi.org/10.1097/ICO.0000000000002327DOI Listing
July 2020

[Distinctive Wessely immune ring in keratitis-a chameleon].

Ophthalmologe 2021 Jan;118(1):53-55

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes UKS, Kirrberger Str. 100, 66421, Homburg, Deutschland.

A Wessely immune ring can be found in various corneal infections as well as in non-infectious processes. Its appearance can aid in the differential diagnosis but can also be misleading. A definitive diagnosis can only be reached when all clinical and microbiological findings are taken into consideration. This article discusses and critically reflects on the differential diagnostic considerations and treatment strategies in the context of a case report on a 31-year-old patient with contact lenses and diffuse endothelial decompensation with a focal, mid-peripheral infiltrate and a Wessely immune ring.
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http://dx.doi.org/10.1007/s00347-020-01084-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7808994PMC
January 2021

Reactive uveitis, retinal vasculitis and scleritis as ocular end-stage of keratitis: a histological study.

Int J Ophthalmol 2019 18;12(12):1966-1971. Epub 2019 Dec 18.

Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar 66424, Germany.

We analysed histologically two keratitis (AK) eyes with anterior and posterior segment inflammation and blindness. Two enucleated eyes of 2 patients (age 45 and 51y) with AK (PCR of epithelial abrasion positive) were analysed. Histological analysis was performed using hematoxylin-eosin, periodic acid-Schiff and Gömöri-methenamine silver staining. We could not observe trophozoites or cysts neither in the cornea nor in other ocular tissues. Meanwhile, we found uveitis, retinal vasculitis and scleritis in these eyes, due to the long-standing, recalcitrant AK. So in this stage of AK, systemic immune suppression may be necessary for a longer time period.
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http://dx.doi.org/10.18240/ijo.2019.12.20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6901890PMC
December 2019

[Correction: Inverted In Vitro Confocal Microscopy in Mycotic Keratitis with Corneal Endothelial Epithelial Decompensation].

Klin Monbl Augenheilkd 2019 Nov 19. Epub 2019 Nov 19.

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes UKS, Homburg/Saar.

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http://dx.doi.org/10.1055/a-1059-9986DOI Listing
November 2019

[Excimer laser-assisted penetrating keratoplasty : On 1 July 2019 excimer laser penetrating keratoplasty celebrates its 30th anniversary. Video article].

Ophthalmologe 2019 Dec;116(12):1221-1230

Klinik für Augenheilkunde und Hochschulambulanz, Universitätsklinikum des Saarlandes UKS, Kirrbergerstr. 100, 66421, Homburg/Saar, Deutschland.

Background And Objective: Since 1986 Naumann and Lang have developed and optimized the technique of nonmechanical corneal trephination using a 193-nm excimer laser along metal masks for penetrating keratoplasty (PKP). The aim of this paper is to demonstrate the technique of excimer laser-assisted keratoplasty.

Methods: After beginning with elliptical transplants a major improvement resulted in the introduction of eight "orientation cogs/notches" at the edges of round metal masks for reduction of "horizontal torsion". For noncontact donor trephination from the epithelial side an artificial anterior chamber is used. The surgical technique is demonstrated in detail and in almost full length in a video of the operation, which is available online.

Results: Prospective clinical studies have shown that the technique of noncontact excimer laser PKP improves donor and recipient misalignment, reduces "vertical tilt" and "horizontal torsion" of the graft in the recipient bed. This results in significantly less keratometric astigmatism, greater regularity of the topography and better spectacle-corrected visual acuity after removal of the sutures. Besides less perioperative disturbance of the blood-intraocular fluid barrier, excimer laser trephination does not induce enhanced cataract formation and does not impair the graft endothelium. Likewise, the rate of immune reactions is not adversely affected by the excimer laser. Furthermore, trephination of an unstable cornea, such as (nearly) perforated corneal ulcers or after radial keratotomy or LASIK is facilitated.

Conclusion: Because of the undisputed clinical advantages, especially in eyes with advanced keratoconus, excimer laser trephination with orientation cogs/notches is currently favored in the routine daily practice in Homburg/Saar.
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http://dx.doi.org/10.1007/s00347-019-00990-wDOI Listing
December 2019

[Inverted In Vitro Confocal Microscopy in Mycotic Keratitis with Corneal Endothelial Epithelial Decompensation].

Klin Monbl Augenheilkd 2019 Dec 31;236(12):1457-1460. Epub 2019 Oct 31.

Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes UKS, Homburg/Saar.

The sensitivity of confocal microscopy ranges between 80 and 90% and thus lies above the sensitivity of pathogen identification by microbiological culture. Typically, in vivo confocal microscopy enables us to diagnose mycotic keratitis non-invasively and atraumatically on the day of admission. Herein we present a patient with an ulcer on a corneal graft, pronounced corneal endothelial epithelial decompensation and a retrocorneal fungal adhesion after repeat-keratoplasty 5 years ago - due to chronic graft rejection after keratoplasty for Fuchs endothelial corneal dystrophy. Clinically there was a suspicion of fungal keratitis. Conventional en face confocal microscopy, however, did not detect hyphae. Due to the pronounced corneal endothelial epithelial decompensation, we were able to detect the fungal hyphae only after repeat penetrating keratoplasty by means of inverted in vitro confocal microscopy on the day of surgery. Histology confirmed the diagnosis of keratomycosis.
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http://dx.doi.org/10.1055/a-0983-1752DOI Listing
December 2019

Early Penetrating Keratoplasty À Chaud May Improve Outcome in Therapy-Resistant Acanthamoeba Keratitis.

Adv Ther 2019 09 17;36(9):2528-2540. Epub 2019 Jul 17.

Department of Ophthalmology, Saarland University Medical Center, UKS, Homburg/Saar, Germany.

Introduction: Long-standing acanthamoeba keratitis (AK) may result in corneal neovascularization, extension of the infiltrate to the limbus or sclera, broad peripheral synechiae, mature cataract or ischemic posterior segment inflammation. We investigated the impact of early emergency penetrating keratoplasty (PKP) in therapy-resistant cases among the patients of a highly specialized tertiary care center.

Methods: In this retrospective, observational cohort within a single institution, we collected data on best-corrected visual acuity (BCVA), epithelial wound healing, graft survival and secondary complications of AK patients who underwent PKP. A total of 23 eyes of 23 patients diagnosed with acute, therapy-resistant AK between 2006 and 2015 were enrolled. Postoperative combined topical treatment was tapered for 6-9 months.

Results: Eyes were grouped based on preoperative disease duration as shorter (group 1) or longer (group 2) than the median. The median was 5.3 (0.66-36) months. The BCVA in group 1 (20/44 ± 20/18; 0.32 ± 0.18 logMAR) was significantly better than in group 2 (20/1200 ± 20/1133; 1.28 ± 0.89; logMAR); p = 0.015. Persisting epithelial defects occurred in 5 patients (50%) of group 1 and in 10 patients (77%) of group 2. In 5 eyes (group 2), no epithelial healing could be achieved. After 36 months, graft survival (Kaplan-Meier) was 78% (18 grafts) for all patients (90% in group 1 and 44% in group 2).

Conclusion: PKP à chaud within 5.3 months after first symptoms of therapy-resistant AK seems to result in better final BCVA than delayed graft surgery if the disease is resistant to a classical topical triple therapy. In addition, early PKP may have a favorable impact on epithelial healing and graft survival.

Funding: We thank the Alexander von Humboldt Foundation for supporting the work of Prof. N. Szentmáry at the Department of Ophthalmology of Saarland University Medical Center in Homburg/Saar, Germany. We thank the University of Saarland for funding the medical writing assistance and the Rapid Service Fees. The funding organisation had no role in the design or conduct of this research.
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http://dx.doi.org/10.1007/s12325-019-01031-3DOI Listing
September 2019
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