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Intraocular pressure (IOP) measurement can be performed with different methods. Newer methods have to be compared to the standard method, the Goldmann applanation tonometry (GAT). We herein compare two air-puff tonometers, the non-contact tonometer (Tomey NCT) and the Corvis ST (CST) with GAT in eyes with a broad spectrum of IOP. Two hundred and forty-nine eyes of 249 patients (with diagnosis of either glaucoma or ocular hypertension) were included in this monocenter prospective cohort study. Each eye underwent IOP measurements via GAT, NCT and CST. Bland–Altman plots were calculated to compare the different methods in the three groups. Paired t tests were used for statistical comparison between the three measurement methods. The difference between the different methods was tested on correlation against central corneal thickness (CCT). Mean IOP in GAT was 17.6 mmHg (standard deviation (SD) 5.9), 16.3 mmHg (SD 5.6) in NCT and 18.0 mmHg (SD 5.5) in CST. Comparisons between GAT and CST vs. NCT showed significant differences (p

The minimally invasive ab-interno trabeculectomy (AIT) via electro-ablation with the Trabectome has been on the European market since 2009. Many studies have proven the safety and efficacy of the procedure. Up until now, studies investigating the long-term effect of AIT have been sparse. In this study, we present long-term results of AIT in patients with primary and secondary open-angle glaucoma. In a retrospective monocentric study, the data of all the patients having undergone the procedure in 2010 at our institution were recorded. Data was collected during routine examinations at our institution. In total, 81 eyes of 74 patients (46 patients with primary open-angle glaucoma (POAG), 28 patients with pseudoexfoliative glaucoma (PEXG)) were included. At every examination, the intraocular pressure (IOP) was measured using Goldmann applanation tonometry and the number of IOP-lowering medication was registered. Statistical analysis was done using the Kaplan-Meier analysis or Dunnett’s t test, respectively. For both groups (POAG and PEXG), we found a significant lowering of the IOP (28% for POAG and 26% for PEXG) and a significant reduction of the number of IOP-lowering medication (32% for POAG and 29% for PEXG) after a median follow-up period of 3.5 years. In patients with open-angle glaucoma and especially pseudoexfoliative glaucoma, ab-interno trabeculectomy is an effective surgical procedure to significantly lower the intraocular pressure on a long-term basis.

Trabectome surgery combined with phacoemulsification is effective in lowering (intraocular pressure) IOP in pseudoexfoliation glaucoma. Trabectome surgery usually aims to remove two to four clock hours of the trabecular meshwork. When adding trabecular aspiration, the remaining meshwork can be treated as well, and therefore 360 degrees of the meshwork can be reached. This study was conducted to investigate the additional benefits and risks of adding trabecular aspiration to the combination of phacoemulsification and trabectome as a triple procedure. Two groups of patients from two centres were compared. The first group underwent phacoemulsification and trabectome (Freiburg), and the second group underwent additional trabecular aspiration (Dusseldorf). Using a case-matched retrospective study design, 50 patients were included into each group. The clinical endpoint was the intraocular pressure at follow up. The mean follow up was 22 months. Mean intraocular pressure decreased in all 100 patients from 25.0 (SD 4.3) to 14.9 mmHg (SD 4.0). Comparing the two groups, the IOP reduction was from 25.0 (SD 5.0) to 14.1 (SD 4.4) mmHg in the triple procedure group compared to a reduction from 25.0 (3.6) to 15.7 (SD 3.4) mmHg in the phaco/trabectome group. The difference was statistically significant (p = 0.03). The number of medication after surgery was reduced from 2.2 (SD 0.9) to 1.7 (SD 0.9) while in the phaco/trabectome group the medication score was reduced from 2.2 (SD 1.0) to 1.1 (SD 0.1) (p

Background Trabeculotomy with the Trabectome® is an effective surgical procedure to lower intraocular pressure (IOP). However, in some patients it does not lead to a significant IOP reduction despite a gonioscopically well visible opening of Schlemm’s canal. This study investigated whether the size of the trabeculotomy opening and other parameters, including anterior chamber depth (ACD) are related to IOP reduction. Methods Retrospective observational case series with 93 eyes of 93 patients who underwent Trabectome surgery. Trabeculotomy opening and ACD were measured with an anterior segment swept source OCT. IOP was taken pre-operatively and at a single follow-up visit [follow-up time 125 ± 66 days (mean ± SD)]. The relationship between IOP reduction and OCT parameters and possible confounding factors was analyzed in a multiple linear regression model. Results The trabeculotomy opening size did not correlate with IOP reduction (slope of regression line = 0.0016; 95% confidence interval of slope: −0.025 to 0.028). The same applied for all other parameters tested, including ACD, which showed a tendency towards better IOP reduction with a deeper AC (slope = −1.9; 95% confidence interval: −5.54 to 1.73). Comparison between the 1st and 4th quartile of the trabeculotomy opening showed a significantly higher ACD in the largest trabeculotomy opening quartile (3.32 ± 0.05 mm vs. 3.16 ± 0.04 mm; p = 0.031). Conclusions The fact that the trabeculotomy opening size did not correlate with IOP reduction points to the poorly understood role of the intrascleral aqueous outflow pathway in glaucomatous IOP elevation. A deeper AC might be a factor promoting a larger trabeculotomy opening. Electronic supplementary material The online version of this article (doi:10.1007/s00417-017-3683-0) contains supplementary material, which is available to authorized users.

We report on a case of a scleral melting as a rare but severe complication of transscleral cyclophotocoagulation. The tissue defect was successfully repaired by tectonic keratoplasty.

Die Augeninnendruck(IOD)-Messwerte nach Laser-in-situ-Keratomileusis (LASIK) bedurfen durch den Abtrag von Hornhautgewebe und dadurch bedingter Verdunnung der Hornhaut einer Korrektur. Mit dem Messgerat Corneal Visualization Scheimpflug Technology (CorVis ST, Oculus, Wetzlar, Germany) werden neben dem IOD und der zentralen Hornhautdicke (CCT), 10 Verformungseigenschaften der Hornhaut quantifiziert. Um die Anderung dieser Parameter und mogliche geeignete Korrekturfaktoren fur die IOD-Messung nach LASIK zu detektieren, wurden Pra- und Post-LASIK-IOD-Messungen mit dem CorVis ST miteinander verglichen. 45 myope Patienten (45 linke Augen) wurden jeweils vor und nach LASIK mit dem CorVis ST gemessen. Messpaare von IOD, CCT und den Verformungseigenschaften (z. B. der Applanationsradius) wurden mittels gepaartem t‑Test verglichen. Zusatzlich wurde die Anderung des IOD-Messwertes in Bezug zu Anderungen der Verformungseigenschaften gesetzt. Es bestatigte sich eine Korrelation der IOD-Messwerte mit der Hornhautdicke. Pro Mikrometer Reduktion der Hornhautdicke misst das CorVis ST den IOD postoperativ um 0,039 mmHg niedriger als praoperativ. Im mehrfaktoriellen linearen Modell zeigen sich auserdem Abhangigkeiten der IOD-Anderung von der A2 velocity und dem Applanationsradius. Nach LASIK zeigt sich auch im CorVis eine Abhangigkeit der IOD-Messung von der Anderung der Hornhautdicke. Die postoperative Anderung der A2 velocity sowie des Applanationsradius haben einen zwar geringen, jedoch ebenfalls signifikanten Einfluss auf die Post-LASIK-IOD-Messung. Unter Berucksichtigung dieser CorVis-Parameter konnte in Zukunft die Druckmessung nach LASIK spezifisch korrigiert werden.

Bernd Junker,1 Jens F Jordan,2 Carsten Framme,1 Amelie Pielen1 1University Eye Hospital, Medical School Hannover, Hannover, 2Eye Center, Medical Center, University of Freiburg, Freiburg, Germany Importance: This study is the first description of the use of the intraoperative optical coherence tomography (iOCT) for trabecular meshwork surgery with the Trabectome in a regular clinical setting.Background: The aim of this study is to evaluate intraoperatively the immediate success of ab interno trabeculotomy with the Trabectome defined as a removal of the trabecular meshwork.Design: This is a retrospective clinical study performed in the University Eye Hospital, Medical School Hannover.Participants: A total of nine consecutive Caucasian patients suffering from primary open angle glaucoma, pigment dispersion glaucoma, or pseudoexfoliation glaucoma took part in the study.Methods: All patients underwent ab interno trabeculotomy surgery with the Trabectome using a commercially available iOCT to visualize the anterior chamber angle (ACA) before and after the procedure. The visualization was done using a modified Swan-Jacobs lens (all nine patients) or without lens (view from above, five patients).Main outcome measures: The main outcome of this study is the success of visualization of the ACA on iOCT, especially the postprocedural visualization of the wound gap after removal of the trabecular meshwork.Results: Using the view from above, the ACA could be visualized before and after the procedure in only two of the five cases. Using the modified Swan-Jacobs lens, the ACA could be visualized before the procedure and the trabecular meshwork opening after the procedure in all nine patients.Conclusion: The iOCT can be used to objectify the immediate success of the surgical procedure, ie, the removal of the trabecular meshwork, of ab interno trabeculotomy with the Trabectome. The procedure itself cannot be captured sufficiently via iOCT. Keywords: glaucoma, imaging, iOCT, trabecular meshwork surgery

Bleb-related infections are serious complications after trabeculectomy. They can be limited to the bleb or disseminate and lead to endophthalmitis. We herein report on all bleb-related infections that have been diagnosed at the Eye Center of the University of Freiburg, Germany, since 1999. We reviewed a total of 1816 consecutive trabeculectomies that were performed at our hospital between the years 1999 and 2014 (353 without and 1463 with intraoperative application of mitomycin C). All bleb-related infections that were diagnosed at our clinic during the same period were included in the analysis. We fitted a Cox proportional hazards model to characterize risk factors for bleb-related infections. We diagnosed a total of 19 bleb-related infections in this period. Three patients with bleb-related infections that came to our clinic had their trabeculectomy performed elsewhere. The overall percentage of bleb-related infections was 0.1% after 2 years (Kaplan–Meier estimate at median follow-up). Nine eyes suffered from only localized infection of the bleb. Seven eyes developed endophthalmitis. Four infections occurred during the first postoperative month. The median age on the day of diagnosis was 71 years; the median age at surgery was 69 years. In the Cox model, intraoperative application of mitomycin C and a fornix-based conjunctival flap were identified as significant risk factors (hazard ratio: 79.02, 4.69; p

Einleitung: Ziel der Studie war es, einen moglichen Einfluss des Body-Mass-Index (BMI) auf das Ergebnis nach Trabektomoperation zu untersuchen. Patienten und Methoden: 131 Augen mit primarem Offenwinkelglaukom (POWG), Myopieglaukom (MG) und Pseudoexfoliationsglaukom (PEXG), bei denen die Indikation zur Trabektomchirurgie gestellt wurde, wurden in diese retrospektive Studie eingeschlossen. Die Daten wurden der Freiburger Trabektomdatenbank von Juni 2009 bis April 2013 entnommen. Mittels eines Cox-Proportional-Hazards-Modells wurde der Einfluss des BMI auf das Operationsergebnis unter Berucksichtigung verschiedener Kovariaten (Alter, praoperative Tropftherapie) berechnet. Ergebnis: Die Gruppe mit einem BMI > 25 kg/m2 weist ein statistisch signifikant schlechteres Ergebnis bezogen auf den absoluten Erfolg (20 % Drucksenkung vom Ausgangsdruck ohne drucksenkende Medikation) nach Trabektomoperation auf (p = 0,047). Hinsichtlich des relativen Erfolgs sowie der Reoperationsrate waren keine statistisch signifikanten Unterschiede zu beobachten. Schlussfolgerung: In unserer Patientenkohorte von 131 Augen war ein hoher BMI mit einer reduzierten Erfolgsaussicht assoziiert, solange ein absoluter Erfolg gefordert wird. Sind Medikamente akzeptabel (relativer Erfolg), ist kein Unterschied zu beobachten.

To evaluate the potential of lowering intraocular pressure in pseudoexfoliation glaucoma with combined phacoemulsification, Trabectome, and trabecular aspiration (triple procedure) compared to phacoemulsification and trabecular aspiration alone. Using a case-matched retrospective study design, 30 patients were included into each group. The main outcome measures were the reduction of intraocular pressure and medication score at the end of follow-up. Clinical data were collected from the patients’ medical records. Mean follow-up was 15 months in both groups. Intraocular pressure decreased from 25.3 ± 6.3 mmHg to 14.4 ± 3.7 mmHg (p

Purpose: The accuracy of Goldmann applanation tonometry (GAT) has been shown to depend on several biomechanical properties of the cornea. Newer tonometry devices (e.g., the Dynamic Contour Tonometer PASCAL? [DCT] and the Tono-Pen? XL [TP]) have been designed to accurately measure intraocular pressure (IOP) independent of corneal thickness (CCT) and pathology. This study investigates the influence of corneal pathologies on the accuracy of these IOP measuring devices, and compares this accuracy to that of direct intracameral IOP measurement. Methods: 8 eyes of 8 patients suffering from corneal pathologies scheduled for penetrating keratoplasty, and 10 eyes of 10 patients scheduled for cataract surgery (control group) were examined. Before surgery, the anterior chamber was cannulated at the temporal corneal limbus. In a closed system, the intraocular pressure (IOP) was directly set to 10, 20, and 30 mmHg with a manometric water column. Intraocular pressure measurements taken by GAT, DCT, and TP were compared to intracameral measurements obtained by a precision reference pressure sensor. Results: Control group: All three methods showed good agreement with the intracameral readings (mean deviation of all three devices, -0.9 mmHg). Group with corneal pathologies: The TP yielded the most exact IOP values in the group with corneal pathologies when taking all diagnoses into account. The mean deviations from the intracameral IOP measurements were -0.9 mmHg ± 3.2 mmHg (mean ± SD) for TP, -2.9 mmHg ± 3.3 mmHg for GAT, and -5.0 mmHg ± 7.9 mmHg for DCT. For bullous keratopathy, the most exact IOP readings were obtained by the TP (mean deviation -0.2 mmHg ± 3.5 mmHg). The TP and GAT devices underestimated IOP in the patients with Fuchs’ endothelial dystrophy; all 3 devices underestimated adjusted IOP after keratoplasty. DCT showed the greatest deviations from adjusted IOP in the case of non-herpetic scars. In the control group, none of the devices showed a statistically relevant dependency on CCT. Nevertheless, in the group with corneal pathologies, only TP showed no dependency on CCT. Conclusion: Our results suggest that the Tono-Pen XL? is the most accurate measurement device to determine IOP in patients with corneal pathologies, especially in patients suffering from corneal edema (bullous keratopathy). GAT yielded surprisingly exact IOP values in patients suffering from irregular corneal surface. DCT showed a high degree of deviation from the adjusted IOP, and should not be used to determine IOP in corneas with the disorders listed here.

PURPOSE: In most forms of open angle glaucoma, the trabecular meshwork is the main barrier for aqueous humor outflow, causing elevated intraocular pressure (IOP). The Trabectome is a minimal invasive device for the surgical treatment of open angle glaucoma, particularly eliminating the juxtacanalicular meshwork. This study was conducted to compare the effectiveness and complication profile among different glaucoma subgroups. METHODS: Single center prospective observational study. There were 557 consecutive eyes of 487 patients included in this study. Trabectome surgery was performed either alone or in combination with cataract surgery. Intraoperative and postoperative complications were documented systematically. Main outcome measures were IOP reduction over time and the preoperative and postoperative number of IOP-lowering medications. Due to subgroup sizes, only data from eyes with primary open angle glaucoma and pseudoexfoliation glaucoma were processed for statistical analysis. RESULTS: For the 261 eyes classified as primary open angle glaucoma, preoperative IOP was 24 ± 5.5 mmHg (mean ± SD) under 2.1 ± 1.3 IOP-lowering medications. After a mean follow-up of 204 ± 238 days, IOP was reduced to 18 ± 6.1 mmHg, and medication was reduced to 1.2 ± 1.1. For the 173 eyes classified as pseudoexfoliation glaucoma, after a mean follow-up of 200 ± 278 days, IOP was reduced from 25 ± 5.9 mmHg to 18 ± 8.2 mmHg, and medication was reduced from 2.0 ± 1.2 to 1.1 ± 1.1. A Cox proportional hazards model hinted forward superiority of the combined surgery cases (Trabectome + Phaco + intraocular lens) in comparison to Trabectome surgery only in phakic or pseudophakic eyes. No serious complications were observed. CONCLUSIONS: Minimal invasive glaucoma surgery with the Trabectome seems to be safe and effective. The subgroup analysis of different kinds of open angle glaucomas presented in this study may help in first-line patient selection. The lack of ocular surface alterations makes it a valuable addition to glaucoma surgery. peerReviewed

Among other corneal biomechanical properties, Goldmann applanation tonometry (GAT) has been shown to depend on corneal edema. New tonometry devices have been designed, such as the Tono-Pen XL, iCare, and ocular response analyzer (ORA), to measure the intraocular pressure (IOP) accurately. This study aims to investigate the influence of corneal edema on the accuracy of these IOP-measuring devices in an in vitro model.A model of an artificial anterior chamber was developed using a guided trephination system. Eight donor corneas not suitable for keratoplasty were clamped into this artificial anterior chamber. All corneas showed signs of stromal edema. Intracameral pressure (ICP) was adjusted manometrically to 10, 20, 30, 40, and 50 mm Hg. The central corneal thickness (CCT) was determined by ultrasonic pachymetry. For each manometrically defined ICP, tonometry was performed using the iCare, Tono-Pen XL, GAT, and ORA.The mean CCT increased from 616.1±29.6 µm to 626.9±36.1 µm. At 10 mm Hg, GAT yielded a higher ICP than those manometrically adjusted (10.4±3.3 mm Hg); at all other ICP levels, GAT yielded lower ICP levels than those adjusted. The Tono-Pen XL and iCare showed the greatest difference at 10 mm Hg, with the Tono-Pen XL yielding a value of 14.0±4.0 mm Hg and the iCare yielding a value of 12.5±2.6 mm Hg. All other results of the 2 devices fell within a range of ±2 mm Hg from the adjusted ICP. The ORA provided accurate results only at "physiological" ICP levels with a maximum difference of 2.6 mm Hg at 30 mm Hg. At higher ICP levels, corneal hysteresis decreased significantly with increasing ICP. None of the measurement devices revealed a statistically relevant dependence on CCT in this experimental setting.The Tono-Pen XL and the iCare yielded the most accurate ICP values across all the adjusted ICP values. This may be because of their relatively small contact area with the cornea and, consequently, greater independence from corneal biomechanical properties. The ORA yielded accurate measurement results only at physiological ICP levels. As anticipated, GAT underestimated ICP. The Tono-Pen XL and the iCare should therefore be used to determine IOP in patients suffering from corneal edema, such as bullous keratopathy or Fuchs endothelial dystrophy.

Hintergrund: Das Glaukom ist eine Augenerkrankung, bei der es zu einer progredienten Schadigung des Sehnervs nach krankheitstypischem Muster kommt. In der Vergangenheit wurde postuliert, dass es durch das Glaukom zu erworbenen Farbsinnstorungen kommt. Bei allen bisher durchgefuhrten Untersuchungen zum Glaukom und zu Farbsinnstorungen wurden jedoch die vaskularen Begleiterkrankungen nicht explizit berucksichtigt. Deshalb war es Ziel dieser Untersuchung, die verschiedenen internistischen Einflussfaktoren auf die Ergebnisse im Farbpigmentprobentest Roth 28-hue (E) desaturiert bei Glaukompatienten zu untersuchen. Patienten und Methoden: 353 Glaukompatienten wurden retrospektiv ausgewertet. Mithilfe einer Varianzanalyse wurde der Einfluss verschiedener Gefaserkrankungen auf die Ergebnisse im Farbpigmentprobentest Roth 28-hue (E) desaturiert bei Glaukompatienten untersucht. Ergebnisse: Es zeigte sich ein deutlicher Einfluss von Alter und mittlerem Gesichtsfelddefekt, sowie unabhangig davon ein Effekt von arteriosklerotischen und vasospastischen Gefaserkrankungen auf die Ergebnisse im Farbpigmentprobentest Roth 28-hue (E) desaturiert. Schlussfolgerung: Die Ergebnisse lassen vermuten, dass arteriosklerotische und vasospastische Gefaserkrankungen unabhangig vom Glaukom einen Einfluss auf das Farbensehen haben. Zukunftig mussen bei Farbsinntests bei Glaukompatienten auch die vaskularen Risikofaktoren berucksichtigt werden.

Purpose Uncontrolled intraocular pressure (IOP) after glaucoma filtration surgery is a challenging problem in the management of glaucoma patients. The Trabectome is a device for selective electroablation of the trabecular meshwork through a clear cornea incision without affecting the conjunctiva. Minimally invasive glaucoma surgery using the Trabectome is safe and effective as primary glaucoma surgery. Here we investigate the results of ab interno trabeculectomy with the Trabectome for IOP control in patients with a failed filtering bleb. Methods A total of 60 eyes of 60 consecutive patients with primary open-angle glaucoma (POAG) or pseudoexfoliative glaucoma (PXG) were enrolled in this single center observational study. Trabectome surgery was performed alone or in combination with phacoemulsification by 2 experienced surgeons. IOP readings and number of IOP lowering medication as primary outcome parameters were taken by an independent examiner. Intraoperative and postoperative medication were recorded systematically. Results Mean IOP before surgery was 24.5±3.5 mm Hg and decreased to 15.7±3.4 (-36%) after mean follow-up of 415 days. The number of necessary IOP lowering medication dropped from 2.1±1.3 to 1.8±1.2 (14% reduction from baseline). A total of 25% (n=15) of cases reported here needed additional surgery after 517 days (range: 6 to 1563 d). No major complications were observed. After mean follow-up, we found a qualified success rate for PXG of 87% and 50% for POAG as revealed by the Kaplan-Meier analysis according to the definitions for success in advanced glaucoma cases according to the World Glaucoma Association (40% reduction from baseline IOP and maximum IOP of 15 mm Hg). Discussion Trabectome surgery for uncontrolled IOP after trabeculectomy is safe and effective especially in PXG patients. Given the demanding subgroup of patients studied here, it is not surprising that success rates are lower compared with previous studies investigating the Trabectome for primary glaucoma surgery. The number of necessary IOP lowering medication drops at first, but seems to reach preoperative values after 20 months of follow-up. Trabectome surgery should be considered as a valuable escape procedure for patients with failed filtering blebs and uncontrolled IOP.

Die klassische Filtrationschirurgie mittels Trabekulektomie oder die Drainage von Kammerwasser mittels episkleraler Implantate sind die effektivsten Methoden, den Augeninnendruck dauerhaft auf niedrig-normale Werte zu senken. Auch wenn beide Operationsverfahren gut etabliert sind, bedingt die hohe Effizienz der Methodik jedoch andererseits potenziell gefahrliche intra- wie postoperative Komplikationen in nicht zu vernachlassigender Haufigkeit. Dies hat in der Vergangenheit dazu gefuhrt, dass mit der nicht perforierenden Glaukomchirurgie („non-penetrating glaucoma surgery“, NPGS) nach komplikationsarmeren Alternativen gesucht wurde – und auch weiterhin gesucht wird. Insbesondere die Trabekelwerkschirurgie hat in diesem Zusammenhang mit kontinuierlich neu entwickelten Operationstechniken den Fokus auf eine komplikationsarme und minimal-invasiv, also gonioskopisch durchfuhrbare Glaukomchirurgie gelenkt.

Hintergrund: Wenig ist auserhalb kleinerer prospektiven Studien bekannt, in welchem Ausmas Patienten mit Pseudoexfoliations-Glaukom bzw. -Syndrom von der kombinierten Katarakt-Trabekelaspirations-Operation im Hinblick auf das Augendruckniveau und den postoperativen Medikamentenbedarf profitieren. Patienten/Material und Methoden: In einer retrospektiven Studie wurde der intraokulare Druck in 104 Augen von 104 Patienten vor und nach kombinierter Phakoemulsifikation und Trabekelaspiration bei Pseudoexfoliations-Glaukom untersucht. Als Erfolg wurde ein drucksenkender Effekt von mindestens 20 % des Ausgangswerts, ein postoperativer Augendruck unter 20 mmHg, eine gleichbleibende oder geringere Anzahl von Antiglaukomatosa und das Fehlen einer Notwendigkeit zur Glaukomchirurgie im postoperativen Verlauf definiert. Ergebnisse: Bei Augen mit praoperativ unzureichendem Tensioniveau (IOD > 20 mmHg) sank der intraokulare Druck im Mittel von 25,4 ± 4,3 mmHg auf 17,0 ± 3,4 mmHg nach 2 Jahren. Die Erfolgsrate lag bei 0,68 nach 1 Jahr und 0,64 nach 2 Jahren. Bei Augen mit regulierten Druckwerten praoperativ war der drucksenkende Effekt gering (17,1 ± 2,3 auf 15,9 ± 2,3 mmHg), allerdings die Medikamentensenkung signifikant. Schlussfolgerung: Die Kombination von Katarakt-Operation und Trabekelaspiration bei Patienten mit PEX-Glaukom hatte auch uber 2 Jahre einen signifikanten druck- bzw. medikamentensenkenden Effekt. Eine Drucksenkung in tiefnormale Bereiche ist allerdings nicht realistisch.

This article presents a case report of unilateral, periocular angioedema after intravenous application of a contrast agent with a temporary increase of intraocular pressure in an eye in which trabeculectomy had been carried out 5 weeks previously.

α-Agonisten werden am Auge zur Behandlung des Glaukoms eingesetzt. Sie senken uber eine Hemmung der Kammerwasserproduktion und uber eine Steigerung des Kammerwasserabflusses den Augeninnendruck. Heutzutage werden aufgrund des geringeren Nebenwirkungsprofils bevorzugt selektive α2-Agonisten angewandt. Sie gehoren aufgrund ihrer lokalen und systemischen Nebenwirkungen jedoch zu den Therapeutika der 2. Wahl. Experimentelle Ergebnisse weisen darauf hin, dass α2-Agonisten einen additiven neuroprotektiven Effekt haben. In klinischen Studien konnte dies jedoch bisher nicht belegt werden.

The correct interpretation of measured tonometric values has become more and more complex in recent years. Large clinical studies have shown that an average central corneal thickness (CCT) of 550 µm can be assumed for the general population. Since the standard Glodmann applanation tonometry is based on a central corneal thickness of 520 µm, mathematical correction formula have been discussed for calculation of the true intraocular pressure. Newer tonometry devices, e. g. the dynamic contour tonometry (DCT) which seems to be independent from CCT, or the Ocular Response Analyzer® (ORA), taking into account the biomechanical properties of the cornea, have been designed to measure intraocular pressure (IOP). In this article, several IOP measurement devices and their clinical relevance for a correct and feasible determination of the IOP are discussed.

Applanation tonometry has been the gold standard in clinical ophthalmology for more than fifty years. The most popular factor is central corneal thickness that is now routinely considered in glaucoma management. However, other individual features of the cornea can also play a key role for the interpretation of the applanation values. Other factors influencing applanation tonometry that have been well known for decades include tear film, fluorescein illumination etc., and should be kept in mind. According to the available literature the absence of a correct calibration cannot be neglected.

BACKGROUND: The aim of this study was to evaluate the concordance of intraocular pressure (IOP) measurements in the supine glaucoma patient using a Perkins applanation tonometer (PAT) compared to the iCare® rebound tonometer (RT), a hand-held device requiring no local anaesthesia. METHODS: 73 left eyes of 73 glaucoma patients were included in this consecutive case study and measured both by supine Perkins applanation tonometry and by right lateral posture rebound tonometry in the supine position (RLP). The patients were divided into three subgroups dependent on IOP (SG-1: 0 - 15 mmHg, SG-2: 16 - 22 mmHg, SG-3: more than 23 mmHg). RESULTS: The mean deviation between RT and PAT was 2.6 ± 4.0 mmHg, the 95 % confidence interval was -5.3 to 10.4 mmHg. 69 % of the measurements showed deviations within 3 mmHg between the two devices. Deviation was smallest in SG-2, and largest in SG-3. CONCLUSIONS: Rebound tonometry is comfortable to use even in supine patients. RT measurement agreed overall significantly with those of Perkins applanation tonometry, generally overestimating PAT measurement. In high IOP values, RT did not correlate as well with PAT as in moderate IOP levels.

The aim of this study is to assess the efficacy and complications of trabeculectomy with a biodegradable implant (ologen implant) vs trabeculectomy using mitomycin C (MMC) in patients with medically uncontrolled open-angle glaucoma in a prospective randomised clinical trial.In the MMC group (10 patients), trabeculectomy was performed according to standard protocols. In the ologen group (10 patients) after standard trabeculectomy the implant was positioned on top of the scleral flap and no MMC was applied. Follow-up was continued for 12 months after surgery and included testing of intraocular pressure (IOP), visual acuity, visual field, ultrasound biomicroscopy, and filtering bleb score.The mean preoperative IOP was 24.8+/-8.9 mm Hg for all patients enrolled. At 1 year after surgery, the mean IOP was 15.6+/-2.4mm Hg in the ologen group (P0.01, 43% reduction) and 11.5+/-4.1 mm Hg in the MMC group (P0.01, 50% reduction). No anti-glaucomatous medication was necessary in the MMC group in the first year of follow-up, whereas five patients in the ologen group required topical treatment. The absolute success rate was 100% in the MMC group and 50% in the ologen group (P=0.01). After 1 year, filtering blebs developed significantly more avascular areas in the MMC group (score=1.4) than in the ologen group (score=2.8; P0.01).The complete success rate using trabeculectomy with the ologen implant is lower than that achieved by trabeculectomy with MMC. However, the bleb morphology caused more problems in the MMC group (avascularity score).

Cyclophotocoagulation is the standard cyclodestructive procedure for treating patients with refractory glaucoma. In addition to transscleral cyclophotocoagulation, endoscopically controlled cyclophotocoagulation (ECPC) is a relatively new method, introduced in the 1990s. Its clinical and technical background is outlined in this article. ECPC allows direct visualization of the ciliary body and better control of the applied laser energy. Therefore, ECPC has been described as being more effective and safer than the transscleral approach. Our own retrospective ECPC data, however, do not indicate that this method can sufficiently decrease intraocular pressure. The indication for the invasive procedure of endoscopic cyclophotocoagulation is therefore questionable.

Background There are few published data on patient satisfaction following glaucoma surgery. The aim of our study was to investigate factors influencing patient satisfaction more than one year after trabeculectomy with mitomycin C. Material and methods We sent a two-page questionnaire to 61 female glaucoma patients who had consecutively undergone filtering surgery with MMC at the Department of Ophthalmology, University of Cologne, requesting anonymous replies (mean follow-up 19.2+/-2.5 months). Results The response rate was 79%. There was no significant inverse correlation between patient satisfaction and recent IOP values, redness of the eye, local irritation or foreign body sensation. There was a significant correlation between patient satisfaction and visual function, a significant inverse correlation between frequency of visits to the ophthalmologist and frequency of eye drop application. A weak, insignificant inverse correlation was found between satisfaction and number of topical medications. Conclusions Patient satisfaction seems to correlate primarily with practical impact on everyday life, visual function, frequency of eye drop application and visits to the eye doctor being identified as the major issues. Local symptoms related to the filtering bleb seem to have a minor influence on patient satisfaction.

Transscleral cyclophotocoagulation is not usually considered as the first line surgical therapy for glaucoma. However, it still remains an important tool for lowering intraocular pressure in certain patients. It is quick and easy to perform and acts through an alternative physiological approach compared to filtration surgery. As the ciliary body is not directly visible, an empirical distance from the limbus is often used for placement of the laser probe; however, the anatomical structures can be highly variable. Diaphanoscopy provides a very simple and effective way to visualize the ciliary body before or parallel to the cyclophotocoagulation. It helps to direct the laser beam more precisely to the ciliary body and to prevent a false anterior placement of the beams, that carries a great risk of side effects. This article provides an overview on the concept of diaphanoscopy for cyclophotocoagulation.

BACKGROUND Small intrascleral foreign bodies of different materials, especially plastic or organic, can sometimes not easily--or not at all--be detected by routine X-ray examination or computed tomography scan. The aim of our study was to evaluate the usefulness of ultrasound biomicroscopy (UBM) with regard to the detection and localisation of such foreign bodies. METHODS An in vitro study with the preparation of a scleral tunnel on 12 porcine eyes was performed. Small foreign bodies of different types of material were placed in the tunnel. The UBM was performed with a Humphrey Ultrasound Biomicroscope, Model 840, to evaluate its diagnostic value in detecting and specifying these sclera-covered foreign bodies. RESULTS Even small foreign bodies of the anterior ocular segment of only 200 microm in size can be detected with the UBM due to the typical ultrasound patterns and artifacts. However, there is no diagnostic specificity for the corresponding material. CONCLUSION The UBM is a high-frequency ultrasonic device with an imaging depth of 5 mm and a spatial resolution of 100 microm. Therefore it is a useful alternative or, respectively, additional diagnostic tool to common imaging techniques like routine X-ray imaging or CT scans, especially in the detection of non-metallic objects. It can provide important information for the ophthalmic surgeon with regard to pre-operative evaluation of the eye. Furthermore, the UBM might even substitute operative exploration of foreign bodies if they are located in the anterior segment of the eye.

BACKGROUND Modern cataract surgery with use of viscoelastics can induce remarkable early spikes of the intraocular pressure (IOP) in patients with glaucoma. PATIENTS AND METHODS The purpose of this prospective study was to investigate risk factors for an early increase of the IOP following cataract surgery in eyes with end-stage glaucoma. Clear cornea phacoemulsification with implantation of a foldable acrylic lens was performed in 25 eyes with end-stage glaucoma (primary open-angle glaucoma including normal tension glaucoma or exfoliative glaucoma) either under topical anesthesia or under general anesthesia. In eyes with exfoliative glaucoma, trabecular aspiration was performed additionally. IOP measurements were conducted at the day before surgery, 4 hours following surgery and on the first morning following surgery. RESULTS Cataract surgery was performed without complications. The mean IOP was 18.5 +/- 4.2 mm Hg with 2.1 +/- 1.0 topical medications. 4 hours postoperatively, mean IOP was 31.3 +/- 11.9 mm Hg. In eyes with exfoliative glaucoma (n = 12) the early postoperative IOP was 28.5 +/- 12.0 mm Hg, but without significant difference compared to eyes with POAG (n = 13). The early postoperative IOP showed significant correlation with the maximum IOP in patient's history (p = 0.014). CONCLUSIONS Patients with late-stage glaucoma can experience considerable early IOP spikes following uneventful cataract surgery, although preoperatively IOP is controlled by topical medications. Postoperative IOP monitoring is recommended at the day of surgery, especially if high IOP values are reported in patient's history.

This article presents a case report of unilateral, periocular angioedema after intravenous application of a contrast agent with a temporary increase of intraocular pressure in an eye in which trabeculectomy had been carried out 5 weeks previously.

Treatment of secondary glaucoma in uveitis patients is challenging. Owing to the young age of these patients, sufficient lowering of the intraocular pressure (IOP) is essential to prevent progression of visual field loss. However, because of the chronic inflammatory stimulus, filtration surgery has an increased risk of failure, especially in patients who have previously undergone surgery. Therefore, minimally invasive glaucoma surgery is a valuable alternative. The clinical records of 24 consecutive patients with uveitic secondary glaucoma who underwent trabeculectomy ab interno with the Trabectome® at the Eye Center of the Albert-Ludwigs University of Freiburg between June 2009 and June 2014 (registered in the Freiburg trabectome database) were retrospectively analyzed. The general baseline information for each patient included age, gender, glaucoma type, ocular medication and current IOP. The postoperative IOP and number of antiglaucomatous medications were recorded at each visit. Statistical analyses were performed using the Kaplan-Meier estimator and Dunnett’s t-test. The mean IOP before surgery was 31 ± 6.7 mmHg (median 32 mmHg). Both the IOP and the number of medications significantly decreased over the various follow-up intervals after trabeculectomy ab interno with the Trabectome®. Patients with follow-ups continuing past one year showed an IOP-reduction of approximately 40 % and a medication number reduction from 2 to 0.67. The failure rate (necessitating further glaucoma surgery) was N = 3 (12.5 %) patients. Trabeculectomy ab interno with the Trabectome® is a minimally invasive and effective method for controlling IOP in uveitic secondary glaucoma.

The main barrier reducing outflow of aqueous humor in open angle glaucomas is the juxtacanalicular trabecular meshwork. The trabectome removes this pathophysiologically altered tissue by electroablation, thus allowing for the collector channels draining Schlemm's canal to directly communicate with the anterior chamber. In studies published so far, about 30% decrease of intraocular pressure and a simultaneous 42% reduction of pressure-lowering eyedrops could be achieved in primary and secondary open angle glaucomas. A clear cornea tunnel is used to advance the trabectome to the trabecular meshwork, leaving the conjunctiva unaffected. Hence minimally invasive chamber angle surgery using this device is in particular suitable for patients with an altered ocular surface. Lowering of intraocular pressure and reduction of needed topical medication seems to be distinct in pseudoexfoliative glaucoma. Surgery with the trabectome and phacoemulsification can easily be combined in one procedure. Using a minimally invasive approach, the complication profile of the trabectome is rather advantageous, not exceeding the general risks of globe-opening surgery. Ab-interno trabeculotomy is a safe and effective method for treatment of patients with primary or secondary open angle glaucomas and moderate target pressures.

The aim of this study was to investigate a possible influence of body mass index (BMI) to the outcome of trabectome surgery.131 eyes with primary open angle glaucoma, myopia-associated glaucoma and pseudoexfoliation glaucoma were included into this retrospective study. The data were extracted from the Freiburg trabectome database from June 2009 to April 2013. We fitted a Cox proportional hazards model in order to assess the influence of the BMI on trabectome outcome.The absolute success after trabectome surgery (20 % pressure reduction without anti-glaucomatous medication) was statistically significantly better in the group with BMI 25 kg/m(2) (p = 0.047). No statistically significant effect was observed for relative success or the rate of re-operation respectively.In our patient cohort of 131 eyes, a high BMI was associated with a reduced success, as long as an absolute success is required. No difference is seen if additional anti-glaucomatous medication is acceptable (relative success).

Primary intraocular lymphoma can cause an elevation of intraocular pressure (IOP), resulting from infiltration of the trabecular meshwork with neoplastic lymphocytes. More rarely, therapeutic procedures can induce a highly synchronised death of tumor cells, leading to congestion of the trabecular meshwork with cell debris. We report on a case of severe IOP elevation after intraocular therapy with methotrexate and rituximab. As medical glaucoma therapy failed, a trabeculotomy with the trabectome was performed, leading to an immediate and sustained decrease in IOP. This novel approach is discussed considering pathogenic aspects of lymphoma-associated glaucoma and alternative surgical techniques.

To compare combined trabectome-cataract surgery with cataract-alone surgery regarding their refractive and visual outcomes and complications. In 137 eyes that underwent combined trabectome-cataract surgery, the postoperative refraction error and best visual acuity after at least 2 months postoperatively were compared to those of an in-house control group of 1,704 eyes that underwent outpatient cataract surgery. Combined trabectome-cataract surgery showed no significant differences regarding the biometry prediction error (BPE, mean 0.53 D vs. 0.48 D, p = 0.24) or visual outcome (BCVA, 0.81 vs. 0.78, p = 0.06). The rate of postoperative cystoid macular edema was slightly higher in the combined surgery group (2.2 % vs. 1.9 %). Refractive and visual outcomes were similar in both groups. Despite the slightly higher rate of postoperative macula edema, we were able to observe that the combination of these two procedures is a feasible method in glaucoma and cataract surgeries.

Background: Hepatorenal tyrosinaemia (Tyr 1) is a rare inborn error of tyrosine metabolism. Without treatment, patients are at high risk of developing acute liver failure, renal dysfunction and in the long run hepatocellular carcinoma. The aim of our study was to collect cross-sectional data. Methods. Via questionnaires we collected retrospective data of 168 patients with Tyr 1 from 21 centres (Europe, Turkey and Israel) about diagnosis, treatment, monitoring and outcome. In a subsequent consensus workshop, we discussed data and clinical implications. Results: Early treatment by NTBC accompanied by diet is essential to prevent serious complications such as liver failure, hepatocellular carcinoma and renal disease. As patients may remain initially asymptomatic or develop uncharacteristic clinical symptoms in the first months of life newborn mass screening using succinylacetone (SA) as a screening parameter in dried blood is mandatory for early diagnosis. NTBC-treatment has to be combined with natural protein restriction supplemented with essential amino acids. NTBC dosage should be reduced to the minimal dose allowing metabolic control, once daily dosing may be an option in older children and adults in order to increase compliance. Metabolic control is judged by SA (below detection limit) in dried blood or urine, plasma tyrosine (, SCOPUS: ar.j, info:eu-repo/semantics/published

We performed a minimally invasive trabeculotomy using a trabectome on a 9-year-old boy with a trauma-related secondary glaucoma where the intraocular pressure (IOP) could not be controlled by conservative approaches. After a 1-year follow-up the patient showed well controlled IOP values without using drugs to reduce pressure.Trabectome surgery seems to be a suitable first step intervention for trauma-related glaucoma in selected cases, even in children.

Glaucoma is an ocular disease with typical progressive damage of the optic nerve. In the past it was postulated that glaucoma induces acquired colour vision disorders. Until now all studies about glaucoma and colour vision disorders did not include vascular risk factors. In the present study we determined several vascular risk factors concerning the results of the colour vision test Roth 28-hue (E) desaturated in glaucoma patients.On the basis of an analysis of variance (ANOVA) we determined the influence of several risk factors, such as arteriosclerotic and vasospastic risk factors, on the results of the colour vision test Roth 28-hue (E) desaturated in glaucoma patients. 353 glaucoma patients were included in this study.We detected a strong influence of age and mean defect in perimetry and an additional effect of arteriosclerotic and vasospastic risk factors on the results of the colour vision test Roth 28-hue (E) desaturated in glaucoma patients.We suspect that arteriosclerotic and vasospastic risk factors independently to glaucoma have an influence on colour vision. In the future attention additionally has to be given to vascular risk factors in the colour vision testing of glaucoma patients.

Trabeculectomy is no longer the gold standard for combined cataract glaucoma surgery considering the successful results following cataract surgery combined with trabeculotomy, viscocanalostomy and canaloplasty. The main disadvantage of these mostly non-penetrating procedures is the induction of conjunctival scarring which jeopardizes subsequent filtering surgery. Ab interno glaucoma surgery, including trabecular surgery and endocyclophotocoagulation, does not interfere with the conjunctival situation. These surgical options have a relatively minor risk profile for combined cataract glaucoma surgery compared to traditional filtering surgery; however, the pressure reducing efficacy of these ab interno approaches is limited with respect to the absolute reduction of intraocular pressure (IOP) and the achievable level of IOP. This has to be kept in mind when planning surgery.

The aim of the present study was to compare the measurement of intraocular pressure (IOP) through a therapeutic soft contact lens with the “native” measurement. We additionally investigate whether a rebound tonometer (RT) or non-contact tonometer (NCT) is more suitable to measure IOP through a bandage contact lens. The IOP was determined using each of the two methods, three times successively with (lens measurement) and without (native measurement) a soft contact lens. The Icare tonometer (Icare® TA01i, Icare Finland Oy, 23 subjects) and the Airpuff tonometer (Nidek NT 53OP, Nidek CO., LTD, Hiroishi Gamagori, Aichi, Japan, 16 subjects) were used. We compared the mean values (validity parameter) and standard deviation (precision parameter) of the three individual measurements in each case using the paired t-test. In addition, we conducted a power analysis to estimate the maximum error in the measurement caused by the contact lens (power level set to 0.8). With the Airpuff tonometer we detected no statistically significant between the lens and the native measurement (15.6 ± 2.6 vs. 15.3 ± 2.6 mmHg; p = 0.42). The power analysis revealed that the maximum error caused by the contact lens was 1.2 mmHg. The Icare tonometry, however, trended toward higher values in the contact lens measurements (17.5 ± 4.3 vs. 16.4 ± 3.5 mmHg in the native measurements; p = 0.05). Interestingly, this difference exhibited a statistically significant correlation with the corneal thickness (0.03 mmHg per μm corneal thickness; p = 0.04). The use of NCT and RT for IOP measurement over a soft contact lens is feasible. The accuracy appears to be sufficient for the most common clinical applications.

The classical filtration surgery with trabeculectomy or drainage of chamber fluid with episcleral implants is the most effective method for permanent reduction of intraocular pressure to lower and normal levels. Even though both operative procedures are well-established the high efficiency of the method causes potentially dangerous intraoperative as well as interoperative complications with a frequency which cannot be ignored. In the past this led to a search for low complication alternatives with non-penetrating glaucoma surgery (NPGS) and the search is still continuing. Trabecular meshwork surgery in particular with continuous development of new operation techniques steered the focus to a complication-poor and minimally invasive, gonioscopic glaucoma surgery.

The aim of this study was to differentiate the pressure-reducing results following trabecular aspiration combined with small incision cataract surgery in eyes with pseudoexfoliation depending on preoperative pressure and medication score.A retrospective analysis was made of 104 exfoliative eyes of 104 patients who underwent combined phaco/trabecular aspiration. Success was defined as a relative reduction of IOP of at least 20 %, absolute IOP of ≤ 20 mmHg, stable or reduced medication score and a lack of any further pressure-reducing surgery.The success rate was 0.68 and 0.64 after 1 and 2 years. In eyes with medically uncontrolled preoperative IOP (20 mmHg) the IOP dropped significantly from 25.4 ± 4.3 mmHg to 17.0 ± 3.4 mmHg after two years. In eyes with preoperative controlled IOP the pressure lowering effect was low (17.1 ± 2.3 to 15.9 ± 2.3 mmHg) with a significant reduction of medication.Combined cataract surgery and trabecular aspiration is a reasonable option in exfoliative eyes with IOP values in the low twenties in order to achieve a reduction of topical medications and to reach a stable IOP level.

Applanation tonometry has been the gold standard in clinical ophthalmology for more than fifty years. The most popular factor is central corneal thickness that is now routinely considered in glaucoma management. However, other individual features of the cornea can also play a key role for the interpretation of the applanation values. Other factors influencing applanation tonometry that have been well known for decades include tear film, fluorescein illumination etc., and should be kept in mind. According to the available literature the absence of a correct calibration cannot be neglected.

The correct interpretation of measured tonometric values has become more and more complex in recent years. Large clinical studies have shown that an average central corneal thickness (CCT) of 550 µm can be assumed for the general population. Since the standard Glodmann applanation tonometry is based on a central corneal thickness of 520 µm, mathematical correction formula have been discussed for calculation of the true intraocular pressure. Newer tonometry devices, e. g. the dynamic contour tonometry (DCT) which seems to be independent from CCT, or the Ocular Response Analyzer® (ORA), taking into account the biomechanical properties of the cornea, have been designed to measure intraocular pressure (IOP). In this article, several IOP measurement devices and their clinical relevance for a correct and feasible determination of the IOP are discussed.

The aim of this study was to evaluate the concordance of intraocular pressure (IOP) measurements in the supine glaucoma patient using a Perkins applanation tonometer (PAT) compared to the iCare® rebound tonometer (RT), a hand-held device requiring no local anaesthesia.73 left eyes of 73 glaucoma patients were included in this consecutive case study and measured both by supine Perkins applanation tonometry and by right lateral posture rebound tonometry in the supine position (RLP). The patients were divided into three subgroups dependent on IOP (SG-1: 0 - 15 mmHg, SG-2: 16 - 22 mmHg, SG-3: more than 23 mmHg).The mean deviation between RT and PAT was 2.6 ± 4.0 mmHg, the 95 % confidence interval was -5.3 to 10.4 mmHg. 69 % of the measurements showed deviations within 3 mmHg between the two devices. Deviation was smallest in SG-2, and largest in SG-3.Rebound tonometry is comfortable to use even in supine patients. RT measurement agreed overall significantly with those of Perkins applanation tonometry, generally overestimating PAT measurement. In high IOP values, RT did not correlate as well with PAT as in moderate IOP levels.

The Trabectome provides a new perspective in angle surgery for open angle glaucoma. Through a 1.7 mm clear cornea tunnel, the juxtacanalicular meshwork is electroablated under gonioscopic control. Thereby, the collector channels in the outer wall of Schlemm's canal are uncovered and resistance to trabecular outflow is removed. From the literature and from our own experience, a pressure reduction by 30-35% can be achieved with a simultaneous reduction of eye drops by 50%. The Trabectome can conveniently be combined with phako-emulsification. Serious complications have not yet been reported. As the conjunctiva remains completely untouched, trabeculectomy, if necessary, could be performed without prognostic restrictions. With a realistic target pressure of approximately 16 mmHg, Trabectome surgery is indicated in patients with moderate optic nerve damage.

Fundamental to NASA's Mars Exploration Program (MEP) is an ongoing development of an integrated and coordinated set of possible future candidate missions that meet fundamental science and programmatic objectives of NASA and the Mars scientific community. In the current planning horizon of the NASA MEP, a landed mobile surface exploration mission launching in the 2018 Mars launch opportunity exists as a candidate project to meet MEP in situ science and exploration objectives. This paper describes the proposed mission science objectives and the mission implementation concept developed for the 2018 opportunity. As currently envisioned, this mission concept seeks to explore a yet-to-be-selected site with high preservation potential for physical and chemical biosignatures, evaluate paleoenvironmental conditions, characterize the potential for preservation of biosignatures, and access multiple sequences of geological units in a search for evidence of past life and/or prebiotic chemistry at a site on Mars.

An area of major importance relating to prototype developments in the photovoltaic field is accurate measurement of photovoltaic devices and modules. In this paper are described some measurement irregularities that can affect performance testing of CdS/CdTe devices and modules, and therefore can affect life testing and technical developmental decisions. These irregularities are dependent on the material being tested and on the measurement technique. They especially relate to devices filled with deep-level traps (large diode ideality factors) that can result in an inability to instantaneously equilibrate to an existing or changing bias condition.