[A comparison between absorbable and non-resorbable scleral implants in deep sclerectomy (T-Flux and SK-Gel)]. / Vergleich von resorbierbaren und nichtresorbierbaren skleralen Implantaten bei tiefer Sklerektomie (SK-Gel und T-Flux).

BACKGROUND: The intraocular pressure (IOP) lowering effects of deep sclerectomy (partially combined with phacoemulsification) with different scleral implants (T-Flux- or SK-Gel) were investigated. PATIENTS AND METHODS: In a retrospective study, 72 patients with medically uncontrollable glaucoma underwent non-penetrating deep sclerectomy. Of these, 54 patients received T-Flux implants and 18 SK-Gel implants. Examinations were carried out shortly before and after surgery, as well as after 12 months. RESULTS: Prior to surgery IOP was 18.4+/-5.5 mmHg (n=72) and 12 months after surgery it was 13.1+/-3.8 mmHg (n=65). The number of antiglaucomatous eyedrops used prior to surgery was 2.3+/-1.3 (n=72) and 12 months after surgery 0.2+/-0.6 mmHg (n=65). Secondary IOP-lowering surgery after 12 months was carried out on 15.3% of the operated eyes, and consecutive goniopunctures after 12 months were 25%. No significant differences were found between the two groups. CONCLUSIONS: The short- and mid-term IOP lowering effects in deep sclerectomy with scleral implants were quite satisfying no matter which implant was used. There was no difference in deep sclerectomy whether or not combined with cataract surgery.

Glaucoma progression is associated with decreased blood flow velocities in the short posterior ciliary artery.

BACKGROUND: An altered perfusion of the optic nerve head has been proposed as a pathogenic factor in glaucoma. AIM: To investigate potential differences in the ocular haemodynamics of patients having glaucoma with progressive versus stable disease, as well as healthy volunteers. METHODS: Peak-systolic velocity (PSV), end-diastolic velocity (EDV) and resistivity index in the short posterior ciliary artery (SPCA), central retinal artery (CRA) and ophthalmic artery were recorded in 114 consecutive patients having glaucoma with an intraocular pressure (IOP) < or =21 mm Hg, as well as in 40 healthy volunteers, by colour Doppler imaging (CDI). RESULTS: Of the 114 patients with glaucoma, 12 showed glaucoma progression (follow-up period: mean 295 (standard deviation (SD) (18) days). CDI measurements in these patients showed decreased PSV and EDV in the SPCA (p<0.001 and p<0.05, respectively) and decreased PSV in the CRA compared with patients with stable glaucoma and healthy controls (p<0.05). No differences in flow velocities were found for the ophthalmic artery. IOP and systemic blood pressure was similar in all the three groups. CONCLUSIONS: Progressive glaucoma is associated with decreased blood flow velocities in the small retrobulbar vessels supplying the optic nerve head. The detected difference could represent a risk factor for progression of glaucomatous optic neuropathy.

Volumetric colour Doppler imaging: a useful tool for the determination of ocular blood flow in glaucoma patients?

PURPOSE: Disturbed ocular haemodynamics are discussed to contribute to the pathogenesis of glaucoma. Up to now there is no method available allowing direct determination of blood flow, which is the most relevant dimension for studies on haemodynamics. In this study, volumetric colour Doppler imaging (vCDI) is evaluated systematically in glaucoma patients. METHODS: A Siemens Elegra ultrasound set-up with a linear 7.5 MHz probe was used for all CDI measurements. For vCDI, the cross-sectional area of a vessel and the flow velocity is determined. From both these parameters blood flow can be calculated. Ocular pulse amplitude (OPA) was assessed by the method of Langham using a pneumatic applanation tonometer. RESULTS: (1) Velocity measurements using CDI in the ophthalmic artery and central retinal artery were highly reproducible (n=20). In contrast, reproducibility of vCDI measurements was low (n=20). Reproducibility improved if five vCDI measures were averaged. (2) Results from two different CDI-operators did not differ regarding the velocity measurements, but there was a difference in vCDI measurements (n=20). (3) Results from vCDI did not correlate with measurements of OPA in 69 patients. (4) In 15 patients, vCDI failed to detect changes of ocular perfusion induced by the application of dorzolamide. CONCLUSION: vCDI is not applicable in ophthalmology at present.

[Ocular hemodynamics in normal tension glaucoma: effect of bimatoprost]. / Okuläre Hämodynamik beim Normaldruckglaukom: Effekte von Bimatoprost.

BACKGROUND: Altered ocular perfusion plays a role in the pathophysiology of normal tension glaucoma. Prostaglandin-like substances are very effective in lowering intraocular pressure. Less data are available regarding the influence of these compounds on ocular perfusion. In the present study the effects of bimatoprost, which has recently been shown to increase the vascular tone of ciliary arteries in vitro, on the blood flow velocity are investigated. PATIENTS AND METHODS: n = 9 eyes from 9 normal tension glaucoma patients were subjected to color Doppler imaging (CDI) before and during a 3 - 5 week therapy with bimatoprost. RESULTS: Bimatoprost reduces intraocular pressure from 14.0 +/- 0.4 to 11.0 +/- 0.5 mmHg (n = 9; P < 0.001). Systolic as well as diastolic blood flow velocities, resistive index (RI) and pulsatility index (PI), measured by CDI, were unaltered in the presence of bimatoprost. DISCUSSION: Bimatoprost does not influence blood flow velocities in the retrobulbar vessels. The in vitro observation of increased vascular tone in the presence of bimatoprost seems not to be relevant for ocular hemodynamics.

Reproducibility of blood flow velocity measurements using colour decoded Doppler imaging.

BACKGROUND: It is taken for granted that glaucomatous damage is caused by changed haemodynamics of the retrobulbar vessel system besides other factors such as, for example, an elevated intraocular pressure. This was proven by various studies in which glaucoma patients were shown to have a changed retrobulbar blood flow velocity. In this study, the reliability of measurements of retrobulbar vessel perfusion by colour decoded Doppler imaging (CDI) was evaluated. PATIENTS AND METHODS: A total of 18 healthy volunteers and 15 patients with various glaucoma types were enrolled in this study. Using a CDI system, type Siemens Sonoline Elegra with a combined applicator (7.5L40), retrobulbar vessel perfusions of the ophthalmic artery, the short posterior ciliary arteries, and the long posterior ciliary arteries of each patient were measured six times. In each measurement, pulse amplitude, end-diastolic velocity, maximum systolic velocity, pulsatility index, and resistivity index of the vessels were determined. The reproducibility of measurements was evaluated by the calculation of the intraclass correlation coefficient (ICC) for each parameter. RESULTS: The ICCs for the ophthalmic artery varied from 0.89 to 0.98, for the short posterior ciliary artery from 0.75 to 0.91, and for the long posterior ciliary artery from 0.77 to 0.99 in both the groups. CONCLUSIONS: The ICCs of the repeated measurements reflect a good reproducibility for both the groups with assumed different retrobulbar perfusion. These findings are prerequisites for the use of CDI in clinical practice and research.