Intraocular pressure before and after capsulorhexis using two viscoelastic substances and two surgical approaches in enucleated porcine eyes.

AIM: To investigate the influence of ophthalmic viscoelastic devices (OVDs) and different surgical approaches on the intraocular pressure (IOP) before and after creation of the curvilinear circular capsulorhexis (CCC) as a measure for anterior chamber stability during this maneuver. METHODS: Prospective experimental WetLab study carried out on enucleated porcine eyes. IOP was measured before and after CCC with the iCare Rebound tonometer (iCare ic200; iCare Finland Oy, Vantaa, Finland). The OVDs used were a cohesive one [Z-Hyalin, Carl Zeiss Meditec AG, Germany; hyaluronic acid (HA)] and a dispersive [Z-Celcoat, Carl Zeiss Meditec AG, Germany; hydroxy propylmethylcellulosis (HPMC)]. The CCC was created using Utrata forceps or 23 g microforceps in different combinations with the OVDs. RESULTS: Using the Utrata forceps the IOP dropped from 63.65±6.44 to 11.25±3.63 mm Hg during the CCC. The use of different OVDs made no difference. Using the 23 g microforceps the IOP dropped from 65.35±8.15 to 36.55±6.09 mm Hg. The difference between IOP drop using either Utrata forceps or 23 g microforceps was highly significant regardless of the OVD used. CONCLUSION: Using the sideport for the creation of the capsulorhexis leads to a lesser drop in IOP during this maneuver compared to the main incision in enucleated porcine eyes. The use of different OVD has no significant influence on IOP drop.

[Rebound tonometry with sterilized probes]. / Rebound-Tonometrie mit sterilisierten Sonden.

BACKGROUND: Intraoperative measurement of intraocular pressure (IOP) opens up possibilities to investigate the influence of IOP on the stability of the eyeball during the performance of surgical maneuvers. Few techniques have been described, none of which are commercially available. This study investigated the use of sterilized probes for rebound tonometry, which could be used intraoperatively. MATERIAL AND METHODS: Tonometry was performed on 30 eyes using a noncontact tonometer and rebound tonometry with the iCare 100 and iCare 200 (iCare Finland Oy, Vantaa, Finland) in a sitting and in a supine position. When performing rebound tonometry probes from the package were used sequentially with sterilized probes. The comparability of sterilized and nonsterilized probes was investigated using different rebound tonometers and different settings. RESULTS: Measurements on a sitting subject were comparable with sterilized and nonsterilized probes. Statistically significant comparability was also found in a supine position. Measurements with identically sterilized probes on identically positioned subjects were comparable with iCare 100 und iCare 200 (T2 vs. T4, p = 0.003 und T3 vs. T5 p < 0.001). The comparison of measurements of the original probe with the sterilized probe in a sitting and in a supine position were possible with statistical significance (p < 0.005). Measuring with the iCare 200 in a sitting position showed a slightly lower IOP with the sterilized probe with the difference being statistically significant. DISCUSSION: Single autoclaving does not alter the probes' ability to measure IOP. CONCLUSION: The use of probes which have been sterilized according to the regulations for other surgical instruments opens up new possibilities for the intraoperative measurement of IOP. This facilitates the use in scientific studies on surgical techniques. In the postoperative period the use of sterilized probes can reduce the risk of infection.

Monitoring of central corneal thickness after phacoemulsification-comparison of statical and rotating Scheimpflug pachymetry, and spectral-domain OCT.

AIM: To explore the possibility of deploying three contactless devices (static and rotating Scheimpflug technology, spectral domain optical coherence tomography) for measuring central corneal thickness (CCT) in preoperative and postoperative examinations of cataract patients. METHODS: Totally 72 patients who had undergone surgery without complications were selected. The CCT was measured prior to the operation, as well as on the first, 5th-7th and 28th day following the operation using the Nidek NT 530-P, Sirius®, and Topcon OCT-2000 devices. RESULTS: A significant postoperative increase and subsequent decrease in CCT was identified with all three devices. The correlations were highly significant and thus reflect a very good degree of comparability at all times with the exception of the rotating Scheimpflug camera. The postoperative results from the latter differed significantly from the other devices. The correlations were Sirius/Topcon (P=0.010) and Sirius/Nidek (P<0.0005). No statistically significant difference could be identified in the comparison between Topcon and Nidek (P=0.056). CONCLUSION: All three devices are suitable for postoperative monitoring of CCT. The measurement results are only comparable to a limited extent and not interchangeable in the course of treating a single patient. This is due to the different imaging technology used in the devices and the resulting modalities for conducting the measurements.

[Blood, where no blood should be]. / Blut, wo keines sein sollte.

Intraocular ischemia can lead to an overexpression of vascular endothelial growth factor (VEGF). This in turn can lead to neovascularization in the anterior and/or posterior segment of the eye, e.g. in the iris or the retina. This article reports a case of neovascularization of the lens due to occlusion of the central retinal vein.

[Bilateral postoperative myopic shift and rise in intraocular pressure after cataract surgery]. / Beidseitige postoperative Myopisierung mit Augendruckanstieg nach Kataraktoperation.

Malignant glaucoma describes a rare constellation with shallowing of the anterior chamber and raised intraocular pressure, which can occur after ocular surgery, trauma or spontaneously. The pathophysiological mechanism seems to consist of a posteriorly directed flow of the aqueous humor formed in the ciliary body into or behind the vitreous body. Most cases can only be treated by surgical intervention. This article describes a bilateral postoperative occurrence, which could be successfully treated with medication alone and no need for surgery.

[Laser Iridotomy - In Cases of Acute Angle Closure Only?] / Laseriridotomie ­ nur bei akuter Engwinkelsituation?

The narrowing of the chamber angle-as a result of anatomic predispositions like high hyperopia or increasing lens thickness-poses the greatest risk for acute angle closure. A laser iridotomy counts as a standard procedure in cases of acute angle closure, whereas there are no coherent recommendations or guidelines for a prophylactic therapy. Modern imaging techniques, such as anterior segment optical coherence tomography or Scheimpflug photography, can give valuable information for the planning of treatment. This review presents traditional and modern imaging techniques and summarises recommendations for action in relation to recent publications.

Cataract surgery in patients taking alpha-1 antagonists: know the risks, avoid the complications.

BACKGROUND: The growing use of alpha-1 receptor antagonists in the treatment of benign prostatic hyperplasia (BPH) has created a new problem in ophthalmic surgery, the so-called intraoperative floppy iris syndrome (IFIS). This consists of a billowing iris, insufficient pupillary dilation with progressive intraoperative miosis, and protrusion of iris tissue through the tunnel and side port incision that are made for access to the anterior chamber during surgery. IFIS presents particular difficulties in cataract surgery which is carried out through the pupil with manipulations in the immediate vicinity of the iris. The complications range from poor visibility of the operative field to iris damage with the surgical instruments and to rupture of the posterior capsule, with loss of lens material into the vitreous body. METHODS: Selective literature review. RESULTS: Alpha-blockers have a direct effect on the alpha-receptors of the iris but also induce ultrastructural changes in the iridial stroma, leading to IFIS. The most important factor in avoiding complications of IFIS seems to be the ophthalmic surgeon's knowledge that the patient is taking an alpha-1 receptor antagonist. CONCLUSION: A thorough medical history and an optimized information flow among all physicians treating the patient-the urologist, the family physician, and the ophthalmic surgeon-are essential for safe cataract surgery.

Web-based training in German university eye hospitals - Education 2.0?

PURPOSE: To analyse web-based training in ophthalmology offered by German university eye hospitals. METHODS: In January 2010 the websites of all 36 German university hospitals were searched for information provided for visitors, students and doctors alike. We evaluated the offer in terms of quantity and quality. RESULTS: All websites could be accessed at the time of the study. 28 pages provided information for students and doctors, one page only for students, three exclusively for doctors. Four pages didn't offer any information for these target groups. The websites offered information on events like congresses or students curricular education, there were also material for download for these events or for other purposes. We found complex e-learning-platforms on 9 pages. These dealt with special ophthalmological topics in a didactic arrangement. In spite of the extensive possibilities offered by the technology of Web 2.0, many conceivable tools were only rarely made available. It was not always possible to determine if the information provided was up-to-date, very often the last actualization of the content was long ago. On one page the date for the last change was stated as 2004. CONCLUSION: Currently there are 9 functional e-learning-applications offered by German university eye hospitals. Two additional hospitals present links to a project of the German Ophthalmological Society. There was a considerable variation in quantity and quality. No website made use of crediting successful studying, e.g. with CME-points or OSCE-credits. All German university eye hospitals present themselves in the World Wide Web. However, the lack of modern, technical as well as didactical state-of-the-art learning applications is alarming as it leaves an essential medium of today's communication unused.

Pre-existing chiasma syndromes do not entirely remit following transsphenoidal surgery for pituitary adenomas.

BACKGROUND: It is not known whether following transsphenoidal surgery for pituitary adenomas the vision of patients with preoperative chiasma syndromes (CS) does improve to the degree of vision of patients without preoperative CS. OBJECTIVE: The purpose of this study is to answer the question above. METHODS: Pertinent data of a successive series of patients operated transsphenoidally for the first time for pituitary adenoma were retrospectively analysed. RESULTS: Of the 304 patients, 35.1% presented preoperatively with CS. The median visual acuity (VA) of these patients improved significantly from preoperative (right eye, 0.63 (0; 1.25); left eye, 0.56 (0; 1.4)) to postoperative (right eye, 0.8 (0; 1.25); left eye, 0.74 (0; 1.25)). The median number of impaired quadrants of the binocular visual fields (VF) improved significantly from preoperative (2 (0; 8)) to postoperative CS (0 (0; 4)). In patients without preoperative CS, postoperative vision (VA as well as VF) remained unchanged. Postoperatively, VA of patients with preoperative CS remained significantly lower than that of patients without preoperative CS (right eye, 0.96 (0.2; 1.4); left eye, 0.94 (0.05; 1.4)). Postoperatively, the number of impaired quadrants of the binocular VF of patients with preoperative CS remained significantly higher than in patients without preoperative CS (0 (0; 1)). CONCLUSION: In this unselected patient series, the vision (VA as well as VF) of patients with preoperative CS did not improved postoperatively to the degree of the vision of patients without preoperative CS. Thus, in patients with adenomatous chiasma compression transsphenoidal surgery may be indicated before CS develops.

Functional impairments caused by chiasma syndromes prior to and following transsphenoidal pituitary adenoma surgery.

PURPOSE: To describe the functional impairment caused by chiasma syndromes (CS) prior to and following transsphenoidal pituitary adenoma surgery. METHODS: Pertinent data of a successive series of patients operated transsphenoidally for the first time for pituitary adenoma were retrospectively analyzed. The degree of functional impairment caused by the impairment of vision was quantified according to the resulting degree of disability (DOD). A DOD of > or =30 is considered substantial. RESULTS: None of the 197 of 304 (64.9%) patients without preoperative chiasma syndrome (CS) experienced postoperative worsening of their visual acuity or their visual fields. Thus, no change of their vision-related DOD (V-DOD) did occur. One hundred and seven (35.1%) of the patients presented preoperatively with CS. Postoperatively, 42.9% of the CS remitted completely, 38.3% improved, 11.2% remained unchanged, and 7.4% worsened. Accordingly, the median V-DOD improved significantly from 30 (0; 100) to 0 (0; 100). The prevalence of patients with V-DOD > or =30 dropped significantly from 51.4% preoperatively to 16.4% postoperatively. Postoperatively, the median V-DOD improved significantly up to 3 months postoperatively. Thereafter, no further significant changes occurred. However, in patients with preoperative CS, the median V-DOD as well as the prevalence of patients with a V-DOD > or =30 remained postoperatively significantly higher compared to patients without preoperative CS. CONCLUSIONS: Visual impairments due to CS frequently caused substantial DOD preoperatively. Postoperatively, the median degree of V-DOD as well as the prevalence of substantial V-DOD improved significantly. However, in patients with preoperative CS, V-DOD remained postoperatively significantly higher than V-DOD of patients without preoperative CS.