[Early effects of clonidine, epinephrine, and pilocarpine on the intraocular pressure and the episcleral venous pressure in normal volunteers (author's transl)]. / Frühwirkungen von Clonidin, Adrenalin und Pilocarpin auf den Augeninnendruck und Episkleralvenendruck des gesunden menschlichen Auges.

In four different groups of eight normal volunteers the intraocular (IOP) and episcleral venous pressures (EVP) were measured before, and at 7.5, 15, 30, 45, and 60 min after topical application of one drop of clonidine (1/4%), epinephrine (1%), or pilocarpine (2%) by means of applanation tonometry or the air-jet method, respectively. The results were compared with a control group. In the control group the IOP decreased by 16% until the fourth measurement. Subsequently it increased to -10% after 60 min. The EVP remained unchanged. After clonidine application the IOP decreased throughout the whole experiment (-31% after 1 h) and after the third measurement the IOP decrease was significantly more marked than in the control group. The EVP I diminished significantly during the first 15 min by 25% and then increased, reaching its initial value after 60 min. IOP and EVP I showed parallel behavior only during the first 30 min. Topical application of epinephrine was followed by a much smaller decrease in IOP (17% after 60 min); compared to the control group the differences were minor. The EVP I was reduced significantly by 15% below the initial level after 45 min while EVP and IOP behaved identically. After pilocarpine application the IOP rose initially (7% after 7.5 min) and decreased markedly after 10 min (33% after 1 h). Compared to the untreated volunteers there were significant differences at nearly all times. At the outset the EVP I increased significantly (29% after 7.5 min), and then decreased again until it regained the initial value after 30 min. Only at the beginning of the experiment were the reactions of IOP and EVP similar.

Determination of pseudofacility in man.

Based on a new method of measuring episcleral venous pressure (EVP), i.e., using the 'air-jet principle' of Krakau et al. (1973), pseudofacility was determined in 20 human eyes. According to Bárány's formula, a mean value of 23.3% of the total facility was found, and a mean value of 16.9% according to Goldmann's formula.

[The influence of changes in body position on intraocular pressure, episcleral venous pressure, and blood pressure (author's transl)]. / Augeninnendruck, Episkleralvenendruck und Blutdruck bei Anderung der Körperlage.

The intraocular pressure, the ophthalmic artery pressure, and the episcleral venous pressure increased after changes from sitting to recumbent body position, whereas the subclavian artery pressure remained unchanged or decreased slightly. Changing from recumbent to sitting position was followed by a decrease in IOP, ophthalmic pressure, and subclavian artery pressure. Comparing the last measurement in the first position to the first value after change, it was found that the IOP alters by about 20%, the ophthalmic artery pressure by 15%, and the episcleral venous pressure by 50%. In all series a decrease in subclavian artery pressure was observed during the first 15 min. The mean pressure in the ophthalmic artery diminished in the series that changed from sitting to recumbent position, whereas it increased in the other series during the first 15 min. The episcleral venous pressure increased more than the corresponding IOP after changing to the recumbent position.

[Ocular blood flow of cats after local administration of pilocarpine, phenylephrine, and of a mixture of both drugs (author's transl)]. / Die Durchblutung des Katzenauges unter lokaler Verabreichung von Pilocarpin, Phenylephrin und einer Kombination beider Pharmaka.

Radioactively labelled microspheres (size 15 micron) were used to determine the regional blood flow in cats before and 15, 30 and 45 minutes after unilateral drug administration. In four experimental groups, each consisting of five animals, two drops of the drug were administered into the conjunctival sac. The blood flow increased in both eyes after administration of 2% pilocarpine and of Glauko Biciron, a mixture of 2% pilocarpine and 0.06% phenylephrine. No significant differences in the regional blood flows between the treated and untreated eye were found. After administration of 2% phenylephrine a decrease in blood flow was observed in both eyes, however earlier and more pronounced in the left eye. Thus, phenylephrine evoked the expected vasoconstrictive effect on the treated side. In the control group, which received physiological salt solution, the blood flow on the treated side decreased in most tissues, while an increase was observed on the untreated side.

[Blood flow through different tissues under clonidine in rabbits (author's transl)]. / Die Durchblutung verschiedener Gewebe des Kaninchens unter Clonidin

The effect of i.v. administered clonidine on the blood flow through different tissues was investigated in six rabbits which had been anaesthetized with NembutalR. Six additional animals served as controls and received an equal quantity of a physiological sodium chloride solution. The blood flow was determined by means of radioactively labelled microspheres just before as well as 15, 30 and 45 min after the administration of the drug or the placebo respectively. In most of the investigated tissues a considerable decrease in blood flow was observed 15 min after the injection of clonidine, whereas no effect was to be seen after administration of sodium chloride. For the first time after 30 min, and even more after 45 min the blood flow diminished as well in the control group. The flow-decreasing effect of clonidine occured in lung, skin, choroid, the small intestine, the triceps muscle, the ciliary body, iris, and white matter, whereas the opposite reaction was observed in liver (hepatic artery), retina and the optic nerve.

Enzymologic and histologic investigations in normal and pressure-ischemic retina of rabbits.

Histologic investigations together with histochemical and photometric measurements of enzyme activities were performed in retina of rabbits, whose blood supply had been totally interrupted for 1h. A retinal edema developed affecting the internal layers between the inner limiting membrane and the internal plexiform and ganglion cell layer. Although this edema was quite remarkable at the posterior pole of the eye, it diminished toward the periphery, disappearing near the ora serrata. The activities of the following enzymes were investigated: hexokinase, glucose 6-phosphate dehydrogenase, aldolase, glyceraldehydephosphate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, ATPase, and phosphorylase. The most striking finding was the total disappearance of phosphorylase activity under pressure ischemia. ATPase and aldolase showed a decreased activity in the ischemic retina, and malate dehydrogenase a slightly diminished one. Concerning the other enzymes, no significant differences between normal and ischemic retina were observed.

[The accuracy of ophthalmodynamometry in the diagnosis of occlusions of the carotid artery (author's transl)]. / Die Treffsicherhiet der Ophthalmodynamometrie bei der Diagnose von Verschlüssen der Arteria carotis

The aim of this study was to evaluate the diagnostic accuracy of ophthalmodynamometry in cases of occlusion of the internal carotid artery. Among the 29 patients examined with ODM there were 12 cases of such an occlusion, which were unknown to the ophthalmological examiner. All of them could be diagnosed exactly. When by means of ODM an occlusion in the region of the common or internal carotid was excluded the result was equally accurate. A decrease in ophthalmic blood pressure by 15% or a side difference of the same degree indicated in 80% of the cases an occlusion of the internal carotid. The ODM seems, therefore, to be a suitable test for finding or excluding such an occlusion.