[Influence of anterior chamber depth on optic disc measurements with OCT and HRT 3]. / Einfluss der Vorderkammertiefe auf die Vermessung des Sehnervenkopfs mit OCT und HRT 3.

BACKGROUND: The aim of this study was to investigate the influence of the anterior chamber depth (ACD) on the measurement of the optic nerve head size with OCT and HRT 3. PATIENTS AND METHODS: 100 pseudophakic eyes of 100 patients were enrolled in this prospective study. The measurement of the optic nerve head was performed with the optical coherence tomography (Stratus OCT, Carl Zeiss Meditec Inc., Dublin, CA) and the confocal laser scanning tomography (Heidelberg retina tomograph, HRT 3, Heidelberg Engineering, GmbH, Dossenheim, Germany). Bland and Altman plots were used to examine the agreement between the parameters of the two techniques. The relationship between the optic nerve head size and the ACD was analysed by linear regression. RESULTS: Optic disc size measurement with the OCT and the HRT 3 showed no significant difference (p = 0.638). Measurement of the optic disc size with the OCT was significantly correlated with the ACD (- 0.234; p = 0.016). The optic disc size decreases with increasing values of the ACD. There was no influence of the ACD on the measurement of the optic disc size with the HRT 3 (r = 0.128; p = 0.193). CONCLUSION: While the optic disc size measured by OCT decreased with increasing ACD, the measurement with the HRT 3 turned out to be independent of the ACD. The OCT may underestimate the optic disc size in lower ACD. This may result in reduced agreement between the two devices.

[Influence of corneal thickness in keratoconic corneas on IOP measurement with IOPen, iCare, dynamic contour tonometry and Goldmann applanation tonometry]. / Einfluss der Hornhautdicke bei Keratokonus auf die Messung des Augeninnendrucks mit 4 verschiedenen Messverfahren.

BACKGROUND: The aim of this study was to evaluate the effect of central corneal thickness (CCT) of keratoconic corneas on intraocular pressure (IOP) measurements as measured by four different techniques. PATIENTS AND METHODS: Forty-one eyes of forty-one keratoconus patients (group 1) and fifty eyes of fifty healthy subjects (group 2) were enrolled. IOP was measured with iCare, IOPen, Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT). CCT was measured by ultrasonic pachymetry. These data were used for statistical analysis. RESULTS: The mean IOPs measured by GAT, DCT, iCare and IOPen were 11.4, 14.7, 10.8, and 15.7 mmHg in group 1; and 14.2, 15.4, 15.4 and 14.3 mmHg in group 2, respectively. Between both groups, there was a statistically significant difference in iCare (p < 0.001), GAT (p < 0.001) and IOPen (p = 0.040) measurements; with no difference between DCT (p = 0.266) measurements. IOPen measurements were significantly associated with CCT (r = - 0.314; p = 0.046). CONCLUSION: IOPen seemed to be affected by CCT. IOP readings by iCare, GAT and DCT were found to be independent of CCT in keratoconic corneas.

[Central toxic keratopathy after photorefractive keratectomy]. / Zentrale toxische Keratopathie nach photorefraktiver Keratektomie.

Central toxic keratopathy is a rare complication following laser-assisted in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) and may unfavorably influence best-corrected visual acuity and refraction. Because of the growing number of refractive surgical procedures worldwide there may be an increasing incidence of this disorder. A differentiation from an inflammatory or infectious etiology is necessary for the appropriate treatment.

[Influence of corneal thickness on intraocular pressure measurements following Descemet's stripping automated endothelial keratoplasty (DSAEK)]. / Einfluss der Hornhautdicke nach posteriorer lamellärer Keratoplastik (DSAEK) auf die Messung des Augeninnendrucks.

BACKGROUND: The aim of this study was to evaluate the effect of increased corneal thickness after Descemet's stripping automated endothelial keratoplasty (DSAEK) on intraocular pressure (IOP) measured by four different techniques. METHODS: In this study 30 eyes from 30 patients with successful DSAEK treatment (group 1) and 30 eyes of 30 healthy subjects (group 2) were enrolled. The IOP was measured with iCare, IOPen, Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT) techniques. Central corneal thickness (CCT) was measured by ultrasonic pachymetry. These data were used for statistical analysis. RESULTS: The mean IOP measured by GAT, DCT, iCare and IOPen was 13.2, 16.1, 12.5 and 14.2 mmHg in group 1 and 13.4, 14.4, 14.4 and 13.3 mmHg in group 2, respectively. Correlations between IOP and CCT were not statistically significant in either group. CONCLUSION: The results of IOP measurements by the iCare, IOPen, GAT and DCT techniques seem to be unrelated to artificially thickened corneas after DSAEK. In spite of partially good correlation between the four techniques a direct exchange of the devices is not recommended on account of the wide dispersion of values.

[Intravitreal implants: drug carriers and carriers of hope?]. / Intravitreale Implantate: Wirkstoff- und "Hoffnungsträger"?

Immunosuppressive agents are used for the therapy of noninfectious uveitis if intraocular quiescence and freedom from recurrences are not achievable with oral steroids at a low dosage. Partially, severe side effects are tolerated to preserve visual acuity even if the disease is limited to the eyes. Because of this a therapy would be desirable which is highly effective, limited to the eyes and with few side effects. For this fluocinolone acetonide and dexamethasone drug delivery systems were developed. Dexamethasone implants were already approved for the therapy of retinal vein occlusions and are used successfully. Diabetic macular edema would be another possible indication for dexamethasone implants.

[Complications after cosmetic iris implantation]. / Komplikationen nach kosmetischer Irisimplantation.

We report the case of a 37-year-old patient with ocular complications associated with the implantation of cosmetic iris implants. Implantation of silicone iris implants for the purpose of changing iris colour has been performed since 2004. Diaphragms are implanted in the anterior chamber. Up to now only little information exists about side effects of this method. In the literature severe ocular complications shortly after cosmetic iris implantation are reported in single cases. In our case 5 months after surgery optic nerve damage caused by elevated intraocular pressure (IOP) was diagnosed. Nuclear opacity of both lenses and a decreased number of corneal endothelial cells were observed at the first visit. Because of recurrent IOP elevation despite maximum antiglaucoma therapy, explantation of the iris implants was required. Damage to the trabecular meshwork, opacity of the lenses as well as the reduced number of endothelial cells are permanent and will probably lead to further complications like corneal decompensation and progressing glaucoma.

[Aqueous humor analysis: a diagnostic tool in intraocular inflammation]. / Kammerwasseranalyse in der Diagnostik intraokularer Entzündungen.

For the diagnosis of unclear intraocular inflammation, the collection of aqueous humor can provide substantial information. Specific procedures including microELISA, polymerase chain reaction (PCR) and cytokine analysis may provide essential diagnostic information. The correct indication and an adequate processing of ocular samples determine the quality and reliability of the laboratory results. This article describes the different considerations and processes that are important to ensure optimal results for these different diagnostic laboratory procedures.

[Intraocular pressure related to uveitis]. / Intraokulare Drucksteigerung bei Uveitis.

Glaucoma, a common and potentially devastating complication of intraocular inflammation, remains a considerable therapeutic challenge. During uveitis, breakdown of the blood-ocular barrier occurs with subsequent influx of proteins as well as inflammatory and immunocompetent cells. These mediators, including cytokines and chemokines, are considered to have a major impact on secondary elevated intraocular pressure (IOP). Several mechanisms are involved in the pathogenesis of inflammatory glaucoma, including obstruction of the trabecular meshwork by inflammatory cells and proteins, trabeculitis, formation of anterior and/or posterior synechiae, pupillary block, neovascularization, and anterior rotation of the lens-iris diaphragm. In addition, the use of steroids to control intraocular inflammation may cause secondary elevation of IOP.The management of uveitic glaucoma requires a careful balance between adequate anti-inflammatory therapy and appropriate lowering of IOP to prevent long-term visual loss. Despite the availability of many new medical treatments for both conditions, control of IOP in these patients remains challenging.

[Mycophenol acid in ocular automimmune disorders--can we optimise this therapy?]. / Ein Beitrag zur Anwendung von Mycophenolsäure bei Autoimmunerkrankungen des Auges: Können wir die Therapie optimieren?

BACKGROUND: Mycophenolate mofetil (MMF) has gained acceptance as an immune modulatory agent in the treatment of autoimmune disorders such as uveitis. It represented a major advance, although optimal use may be limited, in particular, by gastrointestinal (GI) side effects in up to 50 % patients. This prospective study was undertaken to evaluate the effect of conversion from mycophenolate mofetil (MMF) to an enteric-coated mycophenolate sodium (EC-MPS). PATIENTS AND METHODS: Within a cohort of 143 patients treated with MMF we prospectively followed 19 individuals who developed gastrointestinal side effects. Because of limited treatment alternatives, conversion to an enteric-coated mycophenolate sodium (EC-MPS) was undertaken. A standardised questionnaire (GSRS) was completed by each patient regarding GI adverse events, at predefined intervals during the study. RESULTS: The spectrum of underlying disorders included uveitis (n = 16) and ocular cicatricial pemphigoid (n = 3) that were initially treated with MMF (1000 mg BID). All patients could be kept on EC-MPS treatment and followed with a mean follow-up of 44 weeks (median +/- 12). The maximum of scores on GSRS was reached at baseline (conversion to EC-MPS) in all but 3 patients. However, GSRS scores improved significantly between baseline and visit 4 (3 months) and remained stable further on (p < 0.03). In all but one (uveitis) patient the underlying disorders were under control demonstrating the similar efficacies of MMF and EC-MPS treatments. CONCLUSION: The use of EC-MPS appears to be a valid treatment option in ocular autoimmune disorders. In particular. patients with gastrointestinal problems may profit from a significantly reduced frequency of adverse events.

[New trends in tonometry]. / Neue Trends in der Tonometrie.

BACKGROUND: Though the knowledge about the risk of elevated intraocular pressure for pathogenesis for development and progress of glaucoma is more than 400 years old. It took another 300 years before by means of tonometry this elevation could be quantified. After discussion of the key words it is our aim to demonstrate the latest trends in tonometry, specifically by use of modern electronics for instrument design. MATERIALS: Goldmann was the founder of the "applanation tonometry", measuring the corelation of applanated area and applied force. Here, the next step was the development of instruments, measuring independent of position or gravity to allow application also at the lying patient. Electronic area detection was the next step to avoid examinor's error. Also important was the introduction of automatic UV-desinfection to avoid contamination of the other eye or other patients. Other tonometers control the force applied by an inductive method, which also allows application independent of position. Airpuff-tonometry uses completely different measuring principles - the resulting change of corneal curvature indicates the intraocular pressure. The impedance principle is applied even through the closed eye lid. The shock waves resulting shall be measured. Direct application of a surface sensor incorporated into a concave surface contact body shall allow direct measurement of intraocular pressure independent of corneal thickness, curvature, astigmatism. This method has been tried for more than 20 years. Also exposition of the eye to count waves of different frequency was an early attempt. Here also change of reflectivity is used to calculate intraocular pressure. CONCLUSIONS: Even after use of modern electronic technology the precision of many of these new devices does not lead to better results. This specifically is shown by modern calibration methods.

[Clinical Testing of New Tonometers on the Basis of the International Standard for Human eye Tonometers ISO 8612]. / Klinische Erprobung neuer Augentonometer auf der Basis des internationalen Standards für Augentonometer ISO 8612.

There is a continuous process of development of new tonometer types following different measurement principles. The impedance measurement method, using the elasticity of the eyeball, allows tonometry even through the eyelid. Two new tonometers based on the impedance principle were investigated by clinical comparison measurements according to the international standard for human eye tonometers ( ISO 8612). The tested tonometers determine the intraocular pressure without topical anaesthesia. The different elastic properties of an individual eyelid and also the different elastic properties of the human eye due to a large variation in rigidity cause serious problems for these measurements. Statistical properties of the two investigated tonometers are presented and discussed. Statements and conclusions about the medical application of these measurement devices for ophthalmologists are made.

Treatment of rubeosis iridis with photodynamic therapy with verteporfin--A new therapeutic and prophylactic option for patients with the risk of neovascular glaucoma?

Patients with ischaemic retinopathy who show iris neovascularization despite panretinal laser photocoagulation (PRP) very often develop a neovascular glaucoma. Photodynamic therapy (PDT) has been shown to occlude neovascularization without damage to physiologic vessels or adjacent tissue in the treatment of choroidal neovascularization (CNV) and might also be of value for patients with neovascular glaucoma who did not benefit from the PRP. First results of a monocentre, open label, intra-individual controlled, pilot phase I/II, dose-finding study demonstrate that PDT with verteporfin is capable of occluding neovascular vessels for a defined period of time without damaging adjacent tissue or physiologic iris vessels. Whether this vessel occlusion will have an impact on the progression of rubeosis or neovascular glaucoma will be the subject of further investigation.

Development of a completely encapsulated intraocular pressure sensor.

A completely encapsulated intraocular pressure (IOP) sensor equipped with telemetric signal and energy transfer is introduced integrated into a silicone disc for implantation into the eye. After implantation into enucleated pig eyes and into rabbit eyes in vivo, the IOP was recorded and compared to established techniques of IOP measurement. Pressure chamber tests showed that the sensor functioned correctly after biocompatible encapsulation in polydimethylsiloxane. In vivo and in vitro tests in rabbit and pig eyes demonstrated that the implanted system worked with the same precision as established techniques for IOP determination. The correlation between the measurements with the implanted device and pneumotonometry in several experiments was between 0.9 and 0.99. This device serves as a functioning model for the realization of a telemetric IOP sensor for integration into an artificial intraocular lens. Such a device will open new perspectives, not only in the management of glaucoma, but also in basic research for mechanisms of glaucoma.