Enhanced pressure in the central retinal vein decreases the perfusion pressure in the prelaminar region of the optic nerve head.

Purpose: The pressure in the central retinal vein (CRVP) has been shown to be higher in glaucoma patients than in controls. Until now, these measurements have been performed in arbitrary units or in units of ophthalmodynamometric force. In our study, a contact lens dynamometer, calibrated in mm Hg, was used to calculate the retinal perfusion pressure.

The effect of acetazolamide on different ocular vascular beds.

Purpose: To assess the effect of acetazolamide (AZ) on different ocular vascular beds.

Methods: In a prospective study, 32 healthy volunteers (16 male, 16 female) with a mean age of 23.9 ± 3.

Effect of diabetes mellitus on corneal biomechanics and measurement of intraocular pressure.

Purpose:   To determine whether corneal hysteresis (CH) and corneal resistance factor (CRF) are altered in diabetes and whether these parameters are related to HbA1c.

Methods:   One randomly chosen eye of 35 healthy subjects and 31 patients with diabetes was examined. Patients with diabetes were divided into group 1 with HbA1c<7% (n=14) and group 2 with HbA1c≥7% (n=17).

The effect of education on the assessment of optic nerve head photographs for the glaucoma diagnosis.

Background: To evaluate the effect of one lesson of continuing medical education (CME) of subjective assessment of optic nerve head appearance on sensitivity and specificity for the diagnosis of glaucoma.

Methods: Ophthalmologists and residents in ophthalmology attending an international glaucoma meeting arranged at Malmö University Hospital, Malmö, Sweden, were asked to grade optic nerve head (ONH) photographs of healthy and glaucomatous subjects at two sessions separated by a lecture on glaucoma diagnosis by ONH assessment. Each grader had access to an individual portfolio of 50 ONH photographs randomly selected from a web-based data bank including ONH photographs of 73 glaucoma patients and 123 healthy subjects.

Contact lens dynamometry: the influence of age.

Purpose: To examine the influence of age on systolic (systOAP) and diastolic (diastOAP) blood pressure in the ophthalmic artery (OA) measured by a new contact lens dynamometer (CLD).

Methods: In a prospective cross-sectional clinical trial, 106 eyes of 106 patients (58 women, 48 men) were examined. A nearly uniform age distribution was achieved by recruiting subjects in seven age groups, with at least 12 in each decade.

The relationship between central corneal thickness and optic disc size in patients with primary open-angle glaucoma in a hospital-based population.

Purpose: To investigate the relationship between central corneal thickness (CCT) and optic disc size in patients with primary open-angle glaucoma (POAG) in a hospital-based population.

Methods: Data for the right eyes of 1435 White patients with POAG were included in a retrospective hospital-based study. All eyes underwent optic nerve head imaging using Heidelberg Retina Tomograph II (HRT II; Heidelberg Engineering, Heidelberg, Germany) and CCT measurement by ultrasound corneal pachymetry.

Use of the retinal vessel analyzer in ocular blood flow research.

The present article describes a standard instrument for the continuous online determination of retinal vessel diameters, the commercially available retinal vessel analyzer. This report is intended to provide informed guidelines for measuring ocular blood flow with this system. The report describes the principles underlying the method and the instruments currently available, and discusses clinical protocol and the specific parameters measured by the system.

Correlation among choroidal, parapapillary, and retrobulbar vascular parameters in glaucoma.

Purpose: To study and compare the correlation among choroidal, parapapillary, and retrobulbar vascular parameters in healthy subjects, glaucoma suspects, and open-angle glaucoma (OAG) patients.

Design: Prospective observational clinical study.

Methods: The study included one randomly selected eye from 21 normal subjects, 30 glaucoma suspects based on optic disc appearance, and 22 OAG patients.

Dynamic contour tonometry in comparison to intracameral IOP measurements.

Purpose: The purpose of the study was to examine the effect of central corneal thickness (CCT), corneal curvature, astigmatism, axial length (AL), and age on measurements with the Pascal Dynamic Contour Tonometer (DCT).

Methods: In a prospective clinical trial 75 eyes of 75 patients undergoing phacoemulsification were examined. Before phacoemulsification, the anterior chamber was cannulated at the temporal corneal limbus.

A defined change of polarization axis is detected by variable corneal compensation of the GDxVCC.

Purpose: The aim of the study was to examine whether a defined change of polarization axis (PA) is detected by the variable cornea compensation (VCC) of the GDxVCC. The idea behind was to induce a change of PA by a rotation of the eye and to determine whether the rotation affects the magnitude of retardation and retinal nerve fiber layer measurements.

Methods: Fifteen normal eyes were examined with the GDxVCC.

Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry.

Objective: To evaluate the effect of central corneal thickness (CCT), corneal curvature, and axial length on applanation tonometry in an in vivo study.

Methods: In a masked, prospective clinical trial, we examined 125 eyes of 125 patients scheduled for cataract surgery. Corneal curvature was measured by means of keratometry and axial length by A-scan ultrasonography.

A correction formula for the real intraocular pressure after LASIK for the correction of myopic astigmatism.

Purpose: To create a correction formula to determine the real intraocular pressure (IOP) after LASIK considering the altered corneal thickness, corneal curvature, and corneal stability.

Methods: This prospective clinical trial comprised 101 eyes of 59 patients (34 women and 25 men) that underwent LASIK with a mean preoperative spherical equivalent refraction of -6.3 +/- 2.

The effect of age on optic nerve head blood flow.

Purpose: To examine whether optic nerve head blood flow changes with aging.

Methods: One randomly chosen eye of each of 103 healthy subjects (age range, 22-76 years) was examined by laser Doppler flowmetry. Relative capillary blood flow, velocity, and volume of the moving red blood cells were measured at the temporal and nasal neuroretinal rim of the optic nerve head.

The influence of various substances on the biomechanical behavior of lamina cribrosa and peripapillary sclera.

Purpose: Changes in the biomechanical properties of the lamina cribrosa (LC) and of the peripapillary sclera (ppSc) may play a role in the pathogenesis of glaucoma. The purpose of this study was to assess the influence of glyceraldehyde, methylglyoxal, and collagenase A on the mechanical properties of the LC and ppSc.

Methods: Two strips of 1-mm width were cut from each of 80 porcine eyes and 24 pairs of enucleated human eyes.

Visual function and perfusion of the optic nerve head after application of centrally acting calcium-channel blockers.

Background: In a previous study it was shown that nimodipine 30 mg twice daily leads to an improvement in the visual field in a subgroup of normal-pressure glaucoma patients. To understand the mechanism of action of nimodipine on the visual system, the aim of this study was to examine the influence of nimodipine on different hemodynamic parameters and contrast sensitivity in healthy subjects.

Methods: Thirty-two healthy subjects (21-49 years old, mean age 28 years, 10 male, 22 female) received either nimodipine 30 mg twice a day or a placebo according to the same dosage regimen in a double-blind cross-over study design.

Comparison of two grading methods to evaluate focal narrowing of retinal arterioles in glaucoma.

Background: Focal arteriolar narrowing has been reported to be more common in glaucoma eyes compared to normal eyes. The current study was performed to compare two methods for standardized assessment of focal arteriolar narrowing.

Material And Methods: Stereoscopic optic disc photographs (from one randomly selected eye per subject) of 48 normal subjects, 20 ocular hypertensive patients (OHT), and 29 glaucoma patients, were reviewed independently in a masked fashion by two graders.

Using machine learning classifiers to identify glaucomatous change earlier in standard visual fields.

Purpose: To compare the ability of several machine learning classifiers to predict development of abnormal fields at follow-up in ocular hypertensive (OHT) eyes that had normal visual fields in baseline examination.

Methods: The visual fields of 114 eyes of 114 patients with OHT with four or more visual field tests with standard automated perimetry over three or more years and for whom stereophotographs were available were assessed. The mean (+/-SD) number of visual field tests was 7.

The structure-function relationship in eyes with glaucomatous visual field loss that crosses the horizontal meridian.

Objective: To evaluate the relationship between visual field loss and glaucomatous optic discs in eyes in which field loss spreads across the horizontal meridian.

Subjects And Methods: Ninety-six patients with glaucoma (9 advanced, 60 moderate, and 27 early) with 2 successive abnormal fields were included. Standard achromatic automated perimetry defects were identified with a nerve fiber bundle map to identify abnormal sectors.

Comparison of two transducers for color Doppler imaging of the retrobulbar vessels.

Purpose: To compare blood flow velocity measurements obtained with two different linear probes (7.5 MHz and 12 MHz).

Materials And Methods: CDI measurements were performed in 31 eyes of 19 individuals with a 12 MHz and a 7.

Imaging of the optic disc and retinal nerve fiber layer: the effects of age, optic disc area, refractive error, and gender.

We cross-sectionally examined the relationship between age, optic disc area, refraction, and gender and optic disc topography and retinal nerve fiber layer (RNFL) measurements, using optical imaging techniques. One eye from each of 155 Caucasian subjects (age range 23.0-80.