Intraocular pressure measurement with Corvis ST in comparison with applanation tonometry and Tomey non-contact tonometry.

PURPOSE: 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. METHODS: 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). RESULTS: 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 < 0.001), while GAT vs. CST showed no significant difference (p = 0.1162). Mean CCT was 538.7 µm (SD 35.1). CONCLUSIONS: Mean values of GAT and CST show comparable results. However, both GAT and CST differ significantly from NCT. NCT shows lower IOP values compared to both other methods.

Bleb-related infections and long-term follow-up after trabeculectomy.

PURPOSE: 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. METHODS: 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. RESULTS: 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 < 0.01, p < 0.01). The whole group showed a reduction of visual acuity in the median from logMAR 0.12 to 0.2. Eyes that suffered from endophthalmitis showed a loss from 0.3 to 0.96, while the localized infections had a reduction from 0.04 to 0.07. CONCLUSION: Bleb-related infections are a rare complication following trabeculectomy and can be localized on the bleb or can lead to endophthalmitis, thereby threatening visual acuity. The risks and benefits of mitomycin C-augmented trabeculectomies should be taken into consideration.

[Alterations in intraocular pressure and the CorVis parameters after LASIK]. / Änderung des Augeninnendrucks und der CorVis-Parameter nach LASIK.

INTRODUCTION: The reduction of corneal thickness following laser-assisted in-situ keratomileusis (LASIK) requires a correction of intraocular pressure (IOP) measurements. The corneal visualization Scheimpflug technology (CorVis ST, Oculus, Wetzlar, Germany) not only measures the IOP and central corneal thickness (CCT) but also determines 10 additional corneal parameters, such as the time to first and second applanation and velocity. Besides CCT we compared various corneal parameters before and after LASIK in order to detect possible correlations and to correct IOP measurements. METHODS: Measurements with CorVis ST were made before and after LASIK in 45 myopic patients (45 left eyes). We compared the IOP and CorVis ST parameters using a paired t­test before and after LASIK and corrected for possible correlations in a multifactorial linear model. Finally, we correlated the changes in IOP to changes in biomechanical parameters. RESULTS: We observed a direct correlation between the IOP measurements and the corneal thickness. The IOP was underestimated by 0.039 mm Hg per micrometer in reduction of corneal thickness. The multifactorial linear model showed a correlation of IOP change to A2 velocity and the radius of applanation. CONCLUSION: Surgical thinning of the central cornea via LASIK demonstrated a direct correlation between corneal thickness and IOP measurements using the CorVis ST technique. Postoperative changes of the A2 velocity and the applanation radius also had a statistically significant influence on post-LASIK IOP measurements. Our findings could be useful to obtain more precise post-LASIK IOP measurements.

[Diaphanoscopy in cyclophotocoagulation]. / Diaphanoskopie bei der Zyklophotokoagulation.

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.

Refractive and visual outcomes after combined cataract and trabectome surgery: a report on the possible influences of combining cataract and trabectome surgery on refractive and visual outcomes.

PURPOSE: To compare combined trabectome-cataract surgery with cataract-alone surgery regarding their refractive and visual outcomes and complications. METHODS: 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. RESULTS: 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 %). CONCLUSIONS: 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.

[Minimally invasive glaucoma surgery using the trabectome]. / Minimalinvasive Kammerwinkelchirurgie mit dem Trabektom.

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.

[Body mass index as an influencing factor for outcome of trabectome surgery?]. / Einfluss des Body-Mass-Index auf den Erfolg nach Trabektomoperation?

BACKGROUND: The aim of this study was to investigate a possible influence of body mass index (BMI) to the outcome of trabectome surgery. METHODS: 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. RESULTS: 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. CONCLUSION: 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).

[Trauma-related secondary glaucoma in childhood: a therapeutic challenge]. / Traumatisches Sekundärglaukom im Kindesalter : Eine therapeutische Herausforderung.

CASE REPORT: 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. CONCLUSION: Trabectome surgery seems to be a suitable first step intervention for trauma-related glaucoma in selected cases, even in children.