[One-year results after Cypass implantation]. / 1-Jahres-Ergebnisse nach Cypass-Implantation.

BACKGROUND: The Cypass Microstent (Transcend Medical, Menlo Park, CA, USA) is a biocompatible polyamide implant that is implanted in the suprachoroidal space and improves the flow of the aqueous humour via the uveoscleral pathway. MATERIAL AND METHODS: In a retrospective clinical study 162 patients (220 eyes) with an average age of 71.8 (±14.2) years with a mild to moderate glaucoma were treated with a Cypass implant. In the study three groups of patients (group 1, group 2 and group 3) were formed. Group 1 included patients with pseudophakia who received a Cypass implant, group 2 consisted of patients with a Cypass implant combined with phacoemulsification and implantation of an intraocular lens (Phako/HKL) and group 3 included patients who had had multiple eye surgeries before the Cypass implantation. The follow-up period of the study was 1 year. RESULTS: The mean preoperative intraocular pressure (IOP) in group 1 was 20.0 (±8.4) mm Hg and in group 2 was 20.8 (±8.7) mm Hg. The mean IOP fell to 17.7 (±7.1) mm Hg in group 1 (pressure reduction: 11.7%, p < 0.05) and in group 2 to 18.0 (±7.0) mm Hg (pressure reduction: 13.4%, p > 0.05) 12 months postoperatively. The decrease of IOP in group 3 after 1 year was 11.2%. In 20.5% of the cases (45 eyes), additional operative pressure reducing interventions was performed because the target pressure was not achieved. CONCLUSION: After 1 year patients in group 2 showed a significantly similar reduction in pressure as group 1. Additionally, both groups showed a reduction in the number of locally applied antiglaucoma agents. The reduction of the IOP in group 3 was not significant after 12 months, in contrast to the other two groups.

[Morphologic Corneal Changes after Crosslinking for Keratoconus]. / Morphologische Hornhautveränderungen nach Crosslinking bei Keratokonus.

Keratoconus is a relatively common (1 : 2000) bilateral disease leading to a change in biochemical and biomechanical corneal structure as well as thinning and ectasia. For more than 10 years, crosslinking has been a therapeutic option in cases of progression. Using riboflavin and UVA-radiation, the anterior corneal stroma (300 µm) gets stiffened by crosslinking of collagen fibers. When protocols and limitations are adhered, the procedure is described to be effective and of low-risk. This review gives an overview about physiologic and pathologic changes in keratoconic corneas before and after crosslinking. Based on histopathologic examination, the current knowledge in published literature is reviewed and is complemented by our own investigations.

[Complications and postoperative therapeutic strategies in cross-linking]. / Komplikationen und postoperative Therapiestrategien beim Crosslinking.

CLINICAL ISSUE: The reduced corneal mechanical stability in keratoconus and similar collagen diseases can lead to a progressive and irregular corneal shape and decrease of visual acuity. DIAGNOSTICS: A progression of keratectatic diseases can be shown with corneal topography. TREATMENT: Keratoconus can be treated by photo-oxidative cross-linking of the corneal collagen. In order to achieve a high absorption of irradiation energy in the cornea, riboflavin at a concentration of 0.1% and UVA light at a wavelength of 370 nm corresponding to the relative maximum absorption of riboflavin (vitamin B2) are used. Evidence for corneal cross-linking are the increase of biomechanical stiffness, the increased resistance against enzymatic degradation, a higher shrinkage temperature, a lower swelling rate and an increased diameter of collagen fibers. The currently available data demonstrate that the therapeutic cross-linking procedure is safe when respecting the important theoretical and clinical parameters and that a progression of the keratoconus can be avoided. In 80% of cases an average levelling of the curvature of approximately 2 dpt can be achieved, which leads not only to stabilization but also to an increase in visual acuity of approximately 1.2 lines. ASSESSMENT: In a Cochrane review from 2015 publications about complications and results were reviewed. Complication rates ranged from 1-10% depending on the initial situation, comorbidities and stage of the keratoconus. The most important complications are early epithelial wound healing problems as well as extremely rare perforations. PRACTICAL RECOMMENDATIONS: Corneal cross-linking is a well-established and safe procedure but is not free of complications.

[Juvenile idiopathic epiretinal membrane]. / Juvenile idiopathische epiretinale Membran.

Idiopathic epiretinal membrane (iERM) is very rare in adolescent patients. The pathogenesis remains unclear although the role of hyalocytes is of major importance. The clinical features in young patients are different from those in older patients. We describe a case of iERM in a 15-year-old girl who presented with metamorphopsia of the right eye. This case report presents the basis for the decision for surgical treatment as well as the clinical features at follow-up examination 9 months after surgery.

[Low grade endophthalmitis caused by P. acnes : Case report]. / Low-grade-Endophthalmitis verursacht durch P. acnes : Eine Kasuistik.

Low grade endophthalmitis is usually a chronic indolent inflammation that may be misdiagnosed as noninfectious uveitis. Therefore, this form of endophthalmitis is often unsuccessfully treated with corticosteroids. We describe the case of a patient with low grade endophthalmitis caused by Propionibacterium acnes after cataract surgery. This case report presents the difficulties in establishing the diagnosis of this form of endophthalmitis as well as the benefits of a combined operative therapy with pars plana vitrectomy, intravitreal antibiotics and posterior capsulectomy for successful treatment in such cases.

[The German Acanthamoeba keratitis register: Initial results of a multicenter study]. / Das Deutsche Akanthamöbenkeratitis-Register : Erste Ergebnisse einer multizentrischen Erhebung.

BACKGROUND AND PURPOSE: In September 2011 the cornea section of the German Ophthalmological Society (DOG) established the first German Acanthamoeba keratitis registry. The data of this multicenter survey are being collected, compiled and evaluated at the Department of Ophthalmology at the Saarland University. The aim of this article is to present an intermediate report. PATIENTS AND METHODS: Data from 172 eyes with Acanthamoeba keratitis were collected during the last 10 years. For this interim report we actually evaluated 121 eyes (60.2 % female patients, average age 41.3 years) and collected the following data: date of onset of symptoms, date and method of diagnosis, initial diagnosis, anamnestic data, clinical symptoms and signs at diagnosis and during follow-up, conservative and surgical therapy. Criteria for inclusion in the Acanthamoeba registry was the established diagnosis of an Acanthamoeba keratitis with at least one of the methods described in this article. RESULTS: Acanthamoeba keratitis could be histologically proven in 55.3 % of the cases, via PCR in 25.6 %, with confocal microscopy in 20.4 % and using in vitro cultivation in 15.5 %. Clinical symptoms and signs in Acanthamoeba keratitis were pain in 67.0 %, ring infiltrates in 53.4 %, pseudodendritiform epitheliopathy in 11.7 % and keratoneuritis in 5.8 %. In 47.6 % of the cases the initial diagnosis was herpes simplex virus keratitis followed by bacterial keratitis in 25.2 % and fungal keratitis in 3.9 %. Acanthamoeba keratitis was the correct initial diagnosis in only 23.2 % of cases. The average time period between first symptoms and diagnosis was 2.8 ± 4.0 months (range 0-23 months). A triple therapy with Brolene® Lavasept® and antibiotic eye drops at least 5 ×/day was used in 54.5 % of eyes (n = 66). Penetrating keratoplasty was performed in 40.4 %, in 18 cases in combination with cryotherapy of the cornea. The mean graft diameter was 7.9 ± 1.1 mm (range 3.5-11.0 mm). The final visual acuity (Snellen visual acuity chart at 5 m) was comparable in the two groups of eyes with (5/40 ± 5/25) and without (5/32 ± 5/25) keratoplasty. CONCLUSION: Acanthamoeba keratitis is a rare and often very late diagnosed disease and two thirds of the cases were initially misdiagnosed. The early recognition of the typical symptoms is crucial for the prognosis of the disease. All ophthalmological departments in Germany are invited to submit further data of all confirmed cases (berthold.seitz@uks.eu), whether retrospectively or prospectively in order to generate an adequate standardized diagnostic and therapeutic approach for this potentially devastating disease.

[Iatrogenic Keratectasia: A Review]. / Iatrogene Keratektasie - eine Übersicht.

Iatrogenic corneal ectasia is a rare complication but also one of the most feared situations that can occur after uneventful corneal laser surgery. Ectatic changes can occur as early as 1 week or can be delayed up to several years after LASIK. The actual incidence of ectasia is undetermined, an incidence rate of 0.04 to almost 2.8 % has been reported. Ectasia is most common following LASIK; however, cases have been reported following PRK and other corneal refractive procedures. Keratectasia shows progressive myopia, irregular astigmatism, ghosting, fluctuating vision and problems with scotopic vision. The progression leads to severe loss of corrected visual acuity. Risk factors are thin corneas < 500 µm, a pathological corneal topography, a residual stromal bed < 300 µm, high myopia > 8 D, young (female) age < 25 years, atopic dermatitis, allergies, family history for keratokonus and collagen diseases and retreatments. Treatment of choice is a cross-linking with riboflavin/UVA light with contact lenses. In severe cases a penetrating or a deep anterior lamellar graft is necessary.

[Surgical treatment of neovascular glaucoma]. / Operative Therapie des Neovaskularisationsglaukoms.

PURPOSE: The neovascular glaucoma is one of the leading causes for an enucleation. The cyclocryocoagulation, the peripheral retinal cryocoagulation and the intravitreal injection of bevacizumab as combined therapy aim at the reduction of the intraocular pressure and of neovascularisation. MATERIALS AND METHODS: This study follows up 135 patients with neovascular glaucoma who underwent the above-mentioned combined therapy consisting of cyclocryocoagulation, peripheral retinal cryocoagulation and intravitreal injection of bevacizumab. RESULTS: The most common causes of neovascular glaucoma in our study are diabetic retinopathy and central retinal vein occlusion. The intraocular pressure was 37.4 mmHg (± 15.8) mmHg preoperatively under maximum antiglaucomatous therapy and was reduced to 19.0 (± 8.5) mmHg direct postoperatively. In the long-term intraocular pressure remained within the normal range in 93.33 % of patients. A successful reduction of the local antiglaucomatous drops of 1.9 substances to 1.7 substances was observed after 3 months. The oral intake of acetazolamide was also statistically significantly reduced. 47.37 % of the patients were normotensive without local therapy and only 3 patients were still on acetazolamide even after 1 year. The most serious complication was a phthisis bulbi in 1.5 % of patients. Overall 98.5 % of patients remained free of pain and maintained visual acuity after the end of the follow-up. CONCLUSION: Long-term pressure regulation and freedom from pain were successfully achieved. For decompensated neovascular glaucoma with poor vision and painful bulb, the combination of retinal cryocoagulation and intravitreal application of bevacizumab is an important therapeutic option.

[Influence of corneal transparency on the quality of topographies]. / Einfluss der hornhauttransparenz auf die qualität von topografien.

Corneal topographs that measure the anterior and posterior corneal surface with optical methods need a clear cornea for precise measurements. Opacities cause artifacts in the corneal thickness (with measurements usually being too thin) and corneal curvatures. This is important to know as certain pathologies may repeatedly cause similar artifacts. This is highly relevant after a corneal cross-linking, Lasek or PRK, as these procedures cause typical artifacts that can easily be misinterpreted.

[Albumin eye drops for treatment of ocular surface diseases]. / Albumin-Augentropfen zur Behandlung von Augenoberflächenerkrankungen.

For more than 10 years eye drops made from autologous serum have become an established therapy to support corneal wound healing in ocular surface diseases, such as persistent epithelial defects and dry eye. Serum eye drops can only be dispensed by institutions which have obtained a specific license from the appropriate local authorities and this applies to only a few institutes in Germany. The main protein component of serum is albumin which is commercially available as a quality controlled medical product from the pharmaceutical industry and could thus be used as an alternative to autologous serum eye drops. The wound healing effect of albumin eye drops has already been demonstrated in vitro. Here we outline the therapeutic principles and present our first clinical experiences with eye drops made from albumin in the treatment of ocular surface disorders.

[Collagen crosslinking with riboflavin and UVA-light in keratoconus]. / Kollagen-Crosslinking mit Riboflavin und UVA-Licht beim Keratokonus.

Reduced corneal mechanical stability in keratoconus and similar corneal diseases can be treated by photooxidative crosslinking of the corneal collagen. This method is currently undergoing clinical evaluation worldwide. To achieve high absorption of the irradiation energy in the cornea, riboflavin at a concentration of 0.1% and UVA light at a wavelength of 370 nm corresponding to the relative maximum of absorption of riboflavin (vitamin B2) is used. These therapeutic parameters were experimentally tested and have been proven clinically. Current data demonstrate that the therapeutic crosslinking procedure is safe when the important theoretical and clinical parameters are observed, and that progression of keratoconus can be prevented. In all, 80% of the published cases show a decrease in corneal curvature of about 2 D, which leads not only to stabilisation but also to an increase in visual acuity.

[Enzymatic evidence of the depth dependence of stiffening on riboflavin/UVA treated corneas]. / Enzymatischer Nachweis der Tiefenabhängigkeit der Vernetzungswirkung von Riboflavin/UVA an der Hornhaut.

PURPOSE: It has been shown that the treatment of keratoconus with riboflavin/ultraviolet A (UVA) causes significant stiffening of the cornea due to cross-linking. The aim of this study was to evaluate how deep the mechanical stabilization after collagen cross-linking could be shown biochemically. METHOD: Ten out of 20 enucleated porcine eyes were treated with riboflavin as a photosensitizer and UVA (370 nm, 3 mW/cm2, 30 min). The other 10 eyes served as controls. With a Microkeratom device, two flaps with a thickness of 200 microm and a diameter of 8 mm were cut off from each eye and put in a collagenase solution (NaCl plus collagenase A, 1:1). The surfaces of the flaps were measured digitally every day to characterize the dissolving behavior. RESULTS: The resistance (regarding corneal collagen against enzymatic digestion) of the treated superficial flaps was considerably higher (p=0.001) compared to those that were cut secondarily and to the control flaps. But even the flaps from deeper layers showed a significant increase in resistance (p=0.02) compared with the untreated flaps. The half-life of the surfaces of the treated superficial flaps was 220 h; of those cut secondarily, it was 80 h. Both untreated flaps had a half-life of 50 h. CONCLUSIONS: The biochemical study showed that the treatment of the cornea with riboflavin/UVA leads to significant collagen cross-linking not only in the anterior slice of 200 microm but also in the following 200 microm. This locally limited cross-linking effect may be explained by the absorption behavior for UVA of the riboflavin-treated cornea; 65% of UVA irradiation is absorbed in the first 200 microm and only 25-30% in the next 200 microm. Therefore, deeper-lying structures and especially the endothelium are not affected.

[Severe Aspergillus endophthalmitis occurring after liver transplantation in an 8-month-old baby]. / Aspergillus-Endophthalmitis nach Lebertransplantation bei einem Säugling.

Immunosuppressed patients and transplant patients bear an increased risk for invasive aspergillosis and Aspergillus endophthalmitis. An 8-month-old boy developed severe unilateral panuveitis after liver transplantation. Bronchopulmonary infiltrates were present, but a pulmonary Aspergillus infection was not confirmed. An enucleation was performed in order to prevent a life-threatening disseminated Aspergillus infection.

[Corneal aberrations before and after corneal and corneoscleral small incision cataract surgery]. / Korneale Aberrationen vor und nach kornealer und korneoskleraler Kleinschnitt-Katarakt-Chirurgie.

BACKGROUND: The corneal as well as the corneoscleral incisions are considered to be standard in cataract surgery. However, both incision techniques have their advantages and disadvantages. We investigated whether the way of performing the incisions has different effects on the corneal wavefront, especially on higher-order aberrations. METHODS: Each of 26 patients (6 men, 20 women), aged between 62 and 85 years (average 74.9 +/- 6.69 years), received a standard phakoemulsification by performing a corneal incision on the right eye (group 1) and a corneoscleral incision on the left eye (group 2). The corneal surface was preoperatively investigated by using the corneal wavefront instrument Optikon Keratron Scout, (Schwind Company, Germany). After 6 to 8 weeks the same parameters were measured again. RESULTS: The statistical analysis of the pre- and postoperative data within the same group indicated significant differences (p < 0.05) in group 1 for Z (3 +/- 3) = Trefoil and in group 2 for Z (2 +/- 2) = Astigmatism. On comparing the postoperative data of the corneal incision with those of the corneoscleral incision, there was only a significant difference (p < 0.05) for Z (3 +/- 3) = Trefoil. CONCLUSION: In accordance with the induced higher-order aberrations both surgical techniques can be considered as being equivalent.

[The role of pachymetry in routine glaucoma diagnosis]. / Die Rolle der Pachymetrie in der täglichen Glaukomdiagnostik.

The influence of corneal thickness on the precision of Goldman applanation tonometry is highly disputed. Goldmann and Schmidt assumed that the physiological variation of corneal thickness does not influence the measurement. But they indicated that an "abnormal" deviation of corneal thickness can lead to a false measurement. In the last 30 years many investigations have reliably demonstrated that thick corneas produce elevated applanation values and thin corneas lower values. The correction value is 1 mm Hg per 25 microm change in corneal thickness. The accuracy of intraocular pressure measurement is important for the detection and monitoring of glaucoma. Therefore it is necessary to recalculate applanation values based on corneal thickness in every patient, especially after refractive surgery. It is also necessary to keep in mind that with applanation tonometry we measure a force. From the force readings we deduce the value of the intraocular pressure. This conclusion is only correct if the theory of Goldmann applanation tonometry is right. But between force measurement and intraocular pressure there is the individual cornea with special properties like thickness, rigidity and astigmatism which can influence the correctness of the measurement. So we can understand why knowledge of corneal thickness can improve the deduction from force measurement of intraocular pressure. It is also reasonable that other individual corneal properties we do not measure or do not know so far can influence the deduction. This means that the corneal thickness is not the only variable. Pachymetry allows us to estimate the intraocular pressure with higher precision. Therefore it should be clinically used.

[Applanation tonometry in "normal" patients and patients after LASIK]. / Applanationstonometrie bei Normalpatienten und Patienten nach LASIK.

BACKGROUND: Until now it was thought that morphological parameters of the eye such as corneal thickness, corneal curvature and axial length do not affect tonometry results. However, the aim of this study was to find out whether there actually is an influence of these parameters on applanation tonometry. PATIENTS AND METHOD: In this prospective study we examined 125 eyes of 125 normal patients with a corneal thickness of 568.8 +/- 43.79 microm, a corneal curvature of 7.72 +/- 0.27 mm and an axial length of 23.62 +/- 2.05 mm. Before performing a phacoemulsification, the anterior chamber was temporarily punctured. With a closed system the intraocular pressure (IOP) was manometrically set at 20, 35 and 50 mmHg using an H (2)O column. The IOP was then measured with a Perkins tonometer. With these patients we compared 102 eyes that had undergone LASIK due to a myopia of 6.3 +/- 2.17 D. Before and 6 months after surgery, IOD, k-values and central corneal thickness of these patients were measured. RESULTS: At all set pressure levels there was a highly significant correlation of measured IOP and corneal thickness. At all set pressure levels the measured IOP significantly depended on corneal thickness (r(2) = 0.78 - 0.83). After LASIK, IOP was reduced from 16.5 +/- 2.1 to 12.9 +/- 1.9 mmHg. There was a significant correlation between IOP and corneal curvature as well as corneal thickness (r(2) = 0.631; P < 0.001). The biomechanical characteristics of the cornea are changed so that the measured IOP has to be corrected by an additional 0.75 mmHg. CONCLUSION: Since corneal thickness does affect Goldmann applanation tonometry we recommend to use the "Dresden Correction Table" (Tab. ) to achieve the real IOP. Pressure measurements after LASIK are inaccurate because of a change in corneal biomechanics, corneal thickness and curvature and they should be corrected as follows: IOP (real) = IOP (measured) + (540 - CCT)/71 + (43 - K-value)/2.7 + 0.75 mmHg.

[Glaucoma diagnostics and corneal thickness]. / Glaukomdiagnostik und Hornhautdicke.

In recent years the role of pachymetry in the correction of applanation tonometry values was controversially disputed. At the present time it is undoubtedly proven that central corneal thickness affects the accuracy of applanation tonometry. The dimension of this influence is 1 mmHg of pressure per 25 microm of change in corneal thickness. It is important to remember that Goldmann and Schmidt calibrated the applanation tonometer according to the central corneal thickness of their population by using the optical method. Therefore, it is first necessary to determine the corneal thickness for each examiner and his methods. The linear correction formula should be used only in the range of corneal thickness in which the formula was determined. The correction according to Orssengo and Pye and further developments in tonometry may offer alternatives for better estimation of intraocular pressure.

[A new treatment of keratectasia after LASIK by using collagen with riboflavin/UVA light cross-linking]. / Eine neue Behandlung der Keratektasie nach LASIK durch Kollagenvernetzung mit Riboflavin/UVA-Licht.

BACKGROUND: Keratectasia is one of the most severe complications after refractive laser surgery. Usually penetrating keratoplasty is the treatment of choice to achieve an optical rehabilitation in such cases. PATIENTS AND METHODS: We report on a female patient who developed keratectasia in both eyes 4 weeks after LASIK. Due to a severe keratectasia 10 months after LASIK, a treatment with riboflavin/UVA cross-linking was performed. RESULTS: Due to the induced collagen cross-linking the biomechanical status of the cornea was stabilized and a progression of the keratectasia was prevented. The postoperative refraction and corneal topography have been stable for 18 months. CONCLUSION: Collagen cross-linking leads to a stiffening of the anterior parts of the corneal stroma. The increase of biomechanical stability can stop the progression of a keratectasia after LASIK by means of a simple procedure.

[Lacrimal duct treatment with ring intubation in injuries of the upper and lower eyelids]. / Tränenwegsversorgung mittels Ringintubation bei Verletzungen des Ober- und Unterlids.

BACKGROUND: Treating injuries of the lacrimal system with a silicon intubation is an approved method to prevent post-traumatic epiphora. MATERIALS AND METHODS: Between 1990 and 1999, operations were carried out on 44 patients with injuries of the canaliculi with silicon ring intubations. Interesting for us were the age distribution, causes of injuries, localisation and mid- to long-term postoperative complications. RESULTS: The age of the patients was between 1.75 and 74 years, 48% of the injuries were caused by household accidents, 23% by violence, 20% by traffic accidents and 9% by job-related accidents. The canaliculus inferior was injured in 68% of all patients. We found 10 postoperative complications, e.g. ectropia, a too long silicon ring or granuloma. We found a positive anatomical readapted lacrimal system in 88% and 12% of our patients complained of distinct to severe epiphora. CONCLUSIONS: The treatment of lacrimal laceration with a silicon intubation is an excellent method but special care should be taken with correct positioning of the lid margin.