Acta Ophthalmol. 2010: 88: 717–722 Abstract. 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. Unresolved questions and the possible limitations of the technique are also discussed.

A significant correlation of age and bFR was not found in the small sample examined. Untreated arterial hypertension appeared to be associated with a reduced flicker response. The value of such functional vessel properties in the screening of vasosclerosis and in diagnostics in arterial hypertension should be examined in further studies.

ABSTRACT. This review article discusses the relationship between ocular perfusion pressure and glaucoma, including its definition, factors that influence its calculation and epidemiological studies investigating the influence of ocular perfusion pressure on the prevalence, incidence and progression of glaucoma. We also list the possible mechanisms behind this association, and discuss whether it is secondary to changes in intraocular pressure, blood pressure or both. Finally, we describe the circadian variation of ocular perfusion pressure and the effects of systemic and topical medications on it. We believe that the balance between IOP and BP, influenced by the autoregulatory capacity of the eye, is part of what determines whether an individual will develop optic nerve damage. However, prospective, longitudinal studies are needed to better define the role of ocular perfusion pressure in the development and progression of glaucoma.

. The main objective of this report is to encourage consistent quality of testing and reporting within and between centres that use colour Doppler imaging (CDI) for assessment of retrobulbar blood flow. The intention of this review is to standardize methods in CDI assessment that are used widely, but not to exclude other approaches or additional tests that individual laboratories may choose or continue to use.

ABSTRACT.Purpose: Intravitreal injections are used extensively to treat retinal diseases. Performing an intravitreal injection increases intraocular volume by the amount of fluid brought into the eye. Whether this influences intraocular pressure (IOP) was investigated here. Methods: A biomechanical model relying on 3-dimensional elasticity theory was developed to determine the short-term effect of volume changes on IOP. We calculated the effect for intravitreal injections of 0.1 ml in myopic, emmetropic and hyperopic eyes. Our calculations were compared with IOP measurements obtained immediately after intravitreal injection of 4 mg triamcinolone in 0.1 ml solution (IVTA) in 22 patients. Shortly after the measurement had been taken, IOP was reduced by paracentesis. Results: Immediately after IVTA, measured IOP was elevated by a mean of 40.6 ± 12.1 mmHg compared with initial pressure (p < 0.001). Measured and calculated IOP were comparable. Eyes with shorter axial length had higher IOP immediately after the injection (p < 0.05). Conclusions: The effect of injected volumes on IOP can be calculated with a biomechanical model. Our results show that paracentesis might be recommended when injecting 0.1 ml of a substance to avoid a short-term increase in IOP. As intravitreal injections are mostly applied in diseases that are due to vascular compromise, it might be prudent not to impair perfusion in those eyes, even for short periods of time.

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. Purpose:  To compare the influence of aerobic and resistance exercise on intraocular pressure (IOP). Methods:  Twenty‐one healthy subjects participated. Aerobic exercise was performed using a cycle ergometer, and resistance exercise was performed with a leg curl and a butterfly machine. Intraocular pressure was measured at baseline, during exercise and 10 min after. During resistance exercise, a Valsalva manoeuvre was prevented. Results:  Before aerobic exercise, the mean IOP was 18.8 ± 2.7 mmHg. It was 16.5 ± 2.8 after 10, 17.1 ± 2.6 after 20 and 16.7 ± 3.3 mmHg after 30 min of exercise. After 10 min, the IOP returned to baseline (18.8 ± 2.7 mmHg). The mean IOP before resistance exercise with the leg curl machine was 17.0 (15.6–18.4; 65%Wmax) and 16.8 (15.3–18.3) mmHg; 75%Wmax) and did not change significantly during the experiment. The mean IOP before resistance exercise with the butterfly machine (65%Wmax) was 16.4 (15.2–17.6) and increased to 17.2 (16.0–18.4) mmHg (p < 0.05). After 10 min of recreation, it recovered to 16.3 (15.0–17.5) mmHg. At 75%Wmax, the mean baseline IOP was 16.3 (15.2–17.4) mmHg, and there were no significant changes. Conclusions:  Aerobic exercise leads to a significant decrease of IOP. There was no influence of resistance exercise on IOP as long as a Valsalva manoeuvre was prevented.

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