[Corneal refractive surgery despite systemic diseases?] / Refraktive Hornhautchirurgie trotz systemischer Erkrankungen?

According to the literature there are a large number of potential systemic contraindications for corneal refractive surgery. In cases with relative contraindications, surgery should be performed only after weighing up the individual risks and under controlled disease conditions; however, the "evidence" for many of these contraindications is based only on case reports or series, expert opinions or known complications in non-laser-assisted eye surgery. Randomized clinical trials are therefore required.

[Picosecond infrared laser fiber-assisted sclerostomy (PIRL-FAST) : A first proof of principle analysis]. / Pikosekundenlaser-Faser-assistierte Sklerostomie (PIRL-FAST) : Ein erster Machbarkeitsnachweis.

INTRODUCTION: The aim of this study was an analysis of the feasibility of a picosecond infrared laser fiber-assisted sclerostomy (PIRL-FAST) using a novel sapphire fiber and different energy levels of the picosecond laser. METHOD: The laser-assisted sclerostomy was carried out with a newly generated sapphire fiber of the PIRL-HP2-1064 OPA-3000 (Attodyne, Canada). Immediately after the intervention, the eyes were fixed in phosphate-buffered 3.5% formaldehyde. For subsequent histological analysis the eyes were cut into 4 µm thick sections and stained with hematoxylin and eosin (H&E, Merck, Darmstadt, Germany). All preparations were then scanned and digitalized using the MIRAX SCAN (Carl Zeiss Microimaging GmbH, Jena, Germany). RESULTS: The pulse energies 150 µJ (N = 4), 175 µJ (N = 6), 200 µJ (N = 7) and 250 µJ (N = 6) were selected. Within the framework of this first feasibility analysis 400 µm (10 sequential sections) of the sclerotomies were evaluated. The mean area of PIRL-FAST showed a dependency on the pulse energy applied. The diameter of the collateral damage zone (CDZ) depended on the pulse energy used. The largest CDZ could be measured using the highest pulse energy in this experiment (250 µJ). The environmental scanning electron microscope (ESEM) results revealed circular smooth sclerostomy wall with only minimal change of tissue ultrastructure. CONCLUSION: The PIRL-FAST using sapphire fibers is a new minimally invasive instrument to provide robust stenting from the anterior chamber to the subconjunctival space. Since the PIRL has proven to work efficiently in sectioning several tissues with minimal collateral damage these first proof of principle experiments might pave the way for a new minimally invasive glaucoma surgery strategy. We have already initiated experiments to analyze the wound healing and scar formation in vivo.

[Multifocal intraocular lens (MIOL) surgery in young non-presbyopic ametropes : Reasonable and safe?] / Multifokale Intraokularlinsen (MIOL) bei jungen, nicht-presbyopen Patienten : Sinnvoll und sicher?

BACKGROUND: Refractive lens exchange and implantation of a multifocal intraocular lens (MIOL) is mainly advised for ametropes with presbyopia. Non-presbyopic young ametropes who wish spectacle-independence are usually treated with corneal refractive surgery or phakic lenses. OBJECTIVES: This retrospective case series aimed to analyse the refractive and subjective satisfaction outcome after MIOL surgery in both eyes of non-presbyopic ametropes where other treatment options were not possible. MATERIALS AND METHODS: This retrospective case series comprised consecutively treated 32 eyes of 16 patients (5 myopic, 11 hyperopic patients; mean age 31 ± 6 years) who wished spectacle-independence and thus received an aspheric bifocal biconvex refractive-diffractive single-piece MIOL (Acri.Lisa 366/809, Carl Zeiss Meditec AG). Refractive data prior to and after surgery as well as subjective satisfaction at the 1­year follow-up examination were assessed. RESULTS: Related to distance corrected near visual acuity myopic eyes had a median efficacy index (EI) of 0.92 (±0.20) and hyperopes of 0.91 (±0.12) (P = 0.415). For intermediate vision, in both groups a lower EI (<0.5; P = 0.188) resulted in lower subjective satisfaction, which was higher for near and distance vision. Some of hyperopic patients reported limitations in near and distance vision, only one hyperopic patient would not have chosen this surgery again. None had a related complication during the follow-up. CONCLUSIONS: When neither laser refractive surgery nor implantation of a phakic lens is possible, young non-presbyopic ametropes do profit from MIOL surgery with an aspheric bifocal biconvex refractive-diffractive MIOL.

Recurrence rate and subjective symptoms after standardized (Hamburg protocol) phototherapeutic keratectomy on recurrent corneal erosions.

PURPOSE: To evaluate the objective and subjective outcome after phototherapeutic keratectomy (PTK) on recurrent corneal erosions (Hamburg protocol). METHODS: For the standardized PTK according to Hamburg protocol a manual abrasio corneae performed with 20 % alcohol is followed by an excimer ablation depth of ≥15 µm (group1 15 µm; group 2 > 15 µm ablation depth) and 7 mm optical zone. All patients (N = 48) were invited for follow-up examinations and the evaluation of changes concerning subjective symptoms. RESULTS: A significantly reduced subjective impairment of night vision, significantly less pain and less foreign body sensations (for all p < 0.05) were noted in 48 patients that met the inclusion criteria (26 women, 22 men). In the follow-up period an improvement of corrected distance visual acuities (cdva) from 0.80 to 1.08 (group 1) and from 0.58 to 0.99 (group 2) was demonstrated. CONCLUSION: PTK (Hamburg Schema) is a safe and effective procedure to reduce subjective symptoms and improve discomfort in recurrent corneal erosion.

[Unilateral Solar Maculopathy after Gazing at Solar Eclipse]. / Einseitige solare Makulopathie nach Sonnenfinsternis.

A 43-year-old male patient with unilateral metamorphosia presented after gazing at an eclipse with only one eye. Damage of the macula was demonstrated funduscopically, with OCT and angiography. Six weeks after initial presentation and oral methylprednisolone therapy (40 mg/d for 10 days), the symptoms and the morphological changes decreased. Solar retinopathy is a photochemical alteration of the retina, usually seen after sun gazing. In younger patients, it mostly presents as bilateral solar maculopathy. Some patients exhibit partial or total recovery.

[Corneal biomechanics: Corvis® ST parameters after LASIK]. / Korneale Biomechanik : Corvis® ST-Parameter nach Laser-in-situ-Keratomileusis.

BACKGROUND: Corneal refractive surgery alters the biomechanical properties of the cornea. OBJECTIVES: This study was initiated to evaluate corneal biomechanical parameters after LASIK using a Corvis® ST tonometer (CST). METHODS: This retrospective study included 51 eyes of 32 myopic patients. All CST measurements were performed 1 day before surgery and at the 1-month follow-up examination. The LASIK procedure included mechanical flap preparation using a Moria SBK microkeratome and an Allegretto excimer laser platform. RESULTS: Statistically significant differences were observed for mean second applanation length, mean first and second deflection lengths, mean first and second deflection amplitudes, peak distance and radius of curvature. Statistically significant positive correlations were found between the change (Δ) in radius of curvature and Δ in manifest refraction spherical equivalent (MRSE), between the ablation depth and the Δ in intraocular pressure. Applying multiple regression models also revealed statistically significant differences in parameters obtained by CST measurements. CONCLUSION: Several CST parameters were statistically significantly altered by LASIK thereby indicating that flap creation, ablation or both, significantly change the ability of the cornea to absorb or dissipate energy.

[Pachymetry and intraocular pressure measurement by corneal visualization Scheimpflug technology (Corvis ST): A clinical comparison to the gold standard]. / Pachymetrie und Augeninnendruckmessung mittels Corneal-Visualization-Scheimpflug-Technologie (Corvis ST) : Ein klinischer Vergleich zum Goldstandard.

BACKGROUND: Analyses regarding accuracy and reproducibility of intraocular pressure (IOP) measurements and pachymetry with corneal visualization Scheimpflug technology (Corvis ST®, CST). MATERIAL UND METHODS: Retrospective analysis of 72 eyes with primary open angle glaucoma (POAG) and ocular hypertension (OHT) with no prior surgery or other pathology. The results of Goldmann applanation tonometry (GAT), non-contact tonometry (NCT) and ultrasound pachymetry (USP) were compared with repeat measurements with CST. For statistical analyses the t-test and Bland-Altman plots were applied. RESULTS: The mean IOP was 15.5 ± 4.4 mmHg (CST), 14.8 ± 4.4 mmHg (GAT) and 15.6 ± 4.8 mmHg (NCT). The results of GAT and CST as well as GAT and NCT demonstrated statistically significant differences (p < 0.001) whereas NCT and CST displayed no significant differences in IOP (p = 0.72). The mean differences between the repeat measurements were 0.35 ± 1.7 mmHg (CST) and 0.04 ± 0.85 mmHg (GAT). The mean CST pachymetry results showed 551.3 ± 46.5 µm and the USP 526.5 ± 46.4 µm (p < 0.001). The mean difference between the repeated CST measurements was 24.8 ± 21 µm. No repeat measurement data were available for USP. CONCLUSION: The CST is a new device for simultaneously measuring the IOP, pachymetry and biomechanical properties of the cornea. Whether the deviations in the IOP measured by CST and CST pachymetry from the manually performed gold standard has to be evaluated as deficient, tolerable or maybe as an improvement, has to be evaluated in further studies. Because of the automated and contact-free measurement method as well as the potential for simultaneously analyzing biomechanical properties of the cornea, the CST is a device that might help the quest for measuring the 'true' IOP.

[Perspectives of laser-assisted keratoplasty: current overview and first preliminary results with the picosecond infrared laser (λ = 3 µm)]. / Perspektiven der laserassistierten Keratoplastik: Eine aktuelle Übersicht und erste experimentelle Erfahrungen mit dem Pikosekundeninfrarotlaser (λ = 3 µm).

BACKGROUND: This article provides a review of the current state of laser-assisted keratoplasty and describes a first proof of concept study to test the feasibility of a new mid-infrared (MIR) picosecond laser to perform applanation-free corneal trephination. METHODS: The procedure is based on a specially adapted laser system (PIRL-HP2-1064 OPA-3000, Attodyne, Canada) which works with a wavelength of 3,000 ± 90 nm, a pulse duration of 300 ps and a repetition rate of 1 kHz. The picosecond infrared laser (PIRL) beam is delivered to the sample by a custom-made optics system with an implemented scanning mechanism. Corneal specimens were mounted on an artificial anterior chamber and subsequent trephination was performed with the PIRL under stable intraocular pressure conditions. RESULTS: A defined corneal ablation pattern, e.g. circular, linear, rectangular or disc-shaped, can be selected and its specific dimensions are defined by the user. Circular and linear ablation patterns were employed for the incisions in this study. Linear and circular penetrating PIRL incisions were examined by macroscopic inspection, histology, confocal microscopy and environmental scanning electron microscopy (ESEM) for characterization of the incisional quality. Using PIRL reproducible and stable incisions could be made in human and porcine corneal samples with minimal damage to the surrounding tissue. CONCLUSION: The PIRL laser radiation in the mid-infrared spectrum with a wavelength of 3 µm is exactly tuned to one of the dominant vibrational excitation bands of the water molecule, serves as an effective tool for applanation-free corneal incision and might broaden the armamentarium of corneal transplant surgery.

[Difference and distance between the central and thinnest points of the cornea: impact of refractive state, age and ocular side]. / Differenz und Entfernung zwischen zentraler und dünnster Stelle der Hornhaut: Einfluss von Refraktion, Alter und Augenseite.

BACKGROUND: The aim of the study was to quantify the difference in corneal thickness between the central and thinnest points (∆PachyZ-PachyD), the distance between the center of the cornea and its thinnest point (vector length PachyD) and to explore the impact of refractive state, age and ocular side. PATIENTS AND METHODS: This was a multicenter, retrospective, cross-sectional study and medical records of 16,872 eyes were reviewed. The Orbscan® (Bausch and Lomb) procedure was used for pachymetry and keratometry. RESULTS: The results showed that ∆PachyZ-PachyD and vector length PachyD were higher in hyperopic eyes (∆PachyZ-PachyD: 11.99 ± 12.08 µm, vector length PachyD: 0.85 ± 0.44 mm) compared to myopic eyes (∆PachyZ-PachyD: 9.2 ± 7.86 µm, vector length PachyD: 0.7 ± 0.37 mm; p < 0.001). Refractive state, age and ocular side demonstrated an independent, statistically significant impact on ∆PachyZ-PachyD and vector length PachyD. CONCLUSIONS: As a result of the significant impact of refractive state, age and ocular side on ∆PachyZ-PachyD and vector length PachyD, these variables should be considered in a normative data collection.

[Therapeutic excimer laser treatment of the cornea]. / Therapeutische Excimerlaserchirurgie der Hornhaut.

Concomitant with new innovations in the field of refractive surgery, therapeutic excimer laser applications like phototherapeutic keratectomy (PTK) and topography-guided customised ablation treatment are gaining high importance and undergoing rapid evolution. Nowadays, PTK is an effective treatment modality for superficial corneal pathologies. Primary indications are decreased epithelial adherence, superficial opacifications and an irregular corneal surface. For the right indication and successful treatment of corneal pathologies with PTK, a knowledge of the size, depth and nature of the pathology, as well as the refractive status of both eyes is important. Next to slit-lamp examination, objective measuring systems like the topography, confocal microscopy and the anterior segment OCT facilitate presurgical planning. Regarding the treatment procedure the surgeon can choose between a variety of methods. PTK can be combined with manual epithelial debridement or done by only using the excimer laser. In the case of an irregular corneal surface, depending on the pathology, masking fluids or topography-guided custom ablation protocols can increase the visual outcome. To avoid recurrence of the underlying pathology (e.g., corneal dystrophy, haze), the topical application of 0.02% mitomycin C for 20-60 seconds has proved to be a safe and effective procedure. If the surgeon considers all the patient-related factors carefully and manages to combine the available treatment options correctly, PTK embodies an effective and minimally invasive alternative to lamellar or penetrating keratoplasty.

[Infectious keratitis after LASIK--update and survey of the literature]. / Infektiöse Keratitis nach LASIK--aktueller Stand und Literaturübersicht.

LASIK has become the preferred surgical procedure for the correction of refractive errors. Microbial keratitis is a rare but severe complication. The incidence of post-LASIK keratitis, (uni- and bilateral) is difficult to estimate. The risk of bilateral infection could until now only be approximated by calculating it from the risk of unilateral infection. Due to the fortunately low incidence of post-LASIK keratitis, large-scale studies are necessary to obtain valid statistical data. The American Society of Cataract and Refractive surgery (ASCRS) developed a post-LASIK infectious keratitis survey in 2001. 116 post-LASIK infections were reported by the members of the society. The calculated incidence was 0.035 % or 1 infection in every 2919 procedures. Llovet et al. found 9 patients (18 eyes) with bilateral post-LASIK keratitis out of 204 586 procedures (incidence 0.0084 %). Gram-positive bacteria and atypical mycobacteria are the most common causes for microbial post-LASIK keratitis. There is an increasing literature of post-LASIK case reports caused by rare or atypical species. Severe cases of keratitis are more often correlated with a prolonged onset of infection and caused by atypical species. An overview of the current literature and our own data regarding post-LASIK keratitis (uni-, and bilateral) are presented.

[Postkeratoplasty astigmatism: comparison of three suturing techniques]. / Astigmatismus nach perforierender Keratoplastik: Vergleich verschiedener Nahttechniken.

PURPOSE: The aim of this study was a retrospective analysis of postkeratoplasty astigmatism and best corrected visual acuity (BCVA) in patients following penetrating keratoplasty (PK) and a comparison of three suturing techniques. PATIENTS AND METHODS: In this retrospective analysis penetrating keratoplasty (PK) was carried out on 150 eyes with 3 suturing techniques: single running (SR), double running (DR counterclockwise) and interrupted (IR) sutures. Of the eyes 37 (24.7%) underwent PK with SR sutures, 81 eyes (54%) with DR sutures and 32 eyes (21.3%) had IR. PK for Fuchs' dystrophy was used on 46 eyes (30.7%), on 33 eyes (22%) for keratoconus, on 12 eyes (8%) for herpetic keratitis and on 7 eyes (4.6%) for pseudophakic bullous keratopathy. For trephination a guided trephine system (GTS) was used in 44%, rotortrepan in 46.6% and best trepan in 5.3%. Postkeratoplasty astigmatism and best corrected visual acuity (BCVA) were evaluated 1, 4, 12 and 24 months after surgery (all sutures removed). Subjective and objective refractions and corneal topography were performed to assess astigmatism. The Kolmogorov-Smirnov test (95% significance) was used to evaluate statistical significance. RESULTS: Mean topographic astigmatism 4 months (12 months/2 years) after keratoplasty was 4.9 dpt (5.3/4.1, n=4) for SR, 4.2 dpt (4.0/5.3) for DR and 9.7 dpt (n=7) (4.9, n=8/6.8, n=2) for IR suturing techniques. Mean objective astigmatism 4 months (12 months/2 years) after PK was 5.9 dpt (4.1, n=7/5.0, n=3) for SR, 3.4 dpt (4.5/4.98) for DR and 8.0 dpt (n=3) (6.9, n=4/7.4, n=2) for IR sutures. Mean refractive cylinder 4 months (12 months/2 years) after keratoplasty was 4.5 dpt (3.9/4.9) for SR, 3.2 dpt (3.3/3.6) for DR and 6.2 dpt (3.7/4.7) for IR suturing. Mean BCVA 4 months (12 months/2 years) was 0.3 (0.3/0.4) for SR, 0.3 (0.4/0.5) for DR and 0.3 (0.4/0.4) for IR sutures. BCVA 4 months (12 months/2 years) after PK (GTS only) reached 0.3 (0.3/0.5) for SR and 0.3 (0.4/0.6) for DR suturing. DISCUSSION: Topographic and objective astigmatisms were highest for the IR suturing technique. Topographic astigmatism and refractive cylinder were less in the DR (compared to SR) group 4 and 12 months after surgery (statistically significant). After suture removal (2 years after PK) refractive cylinder was still lower for DR compared to SR but there was no statistical difference between DR and SR regarding topographic and objective cylinders. For the interpretation of these data it should be emphasized that due to the retrospective character of this analysis the number of patients in the subgroups is decreasing with time and as a consequence single (strongly deviating) measurements can have a more powerful impact on the outcome in the individual subgroups.

Abiotrophia defectiva endophthalmitis with retinal involvement and infiltrative keratitis: case report and review of the literature.

We report the exceptional case of a severe intraocular Abiotrophia defectiva infection which developed after cataract surgery. Retinal involvement as a complication of A. defectiva endophthalmitis or the combination of acute-onset endophthalmitis with infiltrative keratitis caused by this pathogen has not been described. Moreover, our report represents the first documented ocular A. defectiva infection in Germany. A. defectiva was identified using biotyping and 16S ribosomal RNA gene sequence analysis. Despite vigorous antimicrobial therapy and repeated ocular surgery, visual outcome was poor.

[Acute angle closure glaucoma with unilateral acute loss of vision]. / Akutes Glaukom mit einseitigem akutem Visusverlust.

We report the case of a 31-year-old patient who presented with unilateral acute loss of vision, severe headache, and symptoms of an acute angle-closure glaucoma. Surprisingly, a prepapillary uveal melanoma was the underlying reason; that is, a masquerade syndrome was seen. Enucleation and histopathological investigation of that eye were performed within 3 days after first presentation. Acute angle-closure glaucoma as the initial presentation of uveal melanoma is rare. Nevertheless, clinicians should be aware that patients with refractory unilateral angle-closure glaucoma and asymmetrically opaque media may harbor an occult uveal melanoma.

[Stem cell-based therapies for retinal disorders]. / Stammzellbasierte Therapieansätze für retinale Erkrankungen.

In the context of cell-based therapies for hereditary retinal dystrophies and other retinal disorders, interest has focussed on the therapeutic potential of embryonic and tissue-specific stem cells. Stem cells are characterised by their capacity for self-renewal and by their multipotentiality. Because of these properties, they can be expanded in vitro and eventually differentiated into "desired" specialized cell types. Stem cells are not only candidate cells for the development of cell replacement strategies, but are also interesting cells for the establishment of ex vivo gene therapies. Here, we discuss recent experimental work performed to evaluate the therapeutic potential of embryonic, mesenchymal, hematopoietic, neural and retinal stem cells for the treatment of inherited retinal dystrophies and other retinal diseases.