[Role of active and passive modulations of ocular microcirculation in altering the morphometric parameters of the optic disk in primary glaucoma].

The authors studied the influence of active and passive modulations of ocular microcirculation on the morphometric parameters of the head of the optic nerve and their correlation in patients with primary open-angle glaucoma in the presence of elevated and normalized intraocular pressures (IOP). Ocular microcirculation was examined by the contact method on a LAKK-01 Doppler laser flowmeter. The morphometric parameters were explored by scanning laser ophthalmoscopy on a NRT device. Analysis showed a significant linear correlation of the active and passive modulations of microcirculation with the thickness of a retinal nerve fiber layer, the area and volume of the neuroretinal rim, and the volume profile of excavation in both types of microcirculatory changes. On the bases of the derived ratios, it has been concluded that in patients with the hyperemic type of microcirculation, active modulation mechanisms (enhanced neurogenic and myogenic activities of afferent microvessels) are responsive for glaucomatous optic neuropath in the presence of elevated IOP. In patients with the spastic type, decreased neurogenic and myogenic activities of afferent microvessels are an independent mechanism of tissue damage in the head of the optic nerve in normalized IOP.

[Effect of local hypotensive therapy on ocular hemodynamics in patients with primary open-angle glaucoma]. / Vliianie mestnoi gipotenzivnoi terapii na glaznuiu gemodinamiku u bol'nykh s pervichnoi otkrytougol'noi glaukomoi.

Ocular hemodynamics is followed u p in patients with primary open-angle glaucoma after local application of 1% pilocarpine and 0.5% timolol maleate for 30 days. Forty-two patients (48 eyes) aged 47-82 years with initial, well-developed, and far-advanced condition were followed up. Diastolic, m ean dynamic pressure in the orbital artery, and perfusion pressure were measured. A significant decrease of diastolic pressure in the orbital artery, more expressed during the first ten days was observed in all patients. Later this value increased till the end of follow-up, but did not reach the initial level. Hence, patients with visual field loss are characterized by a higher local vascular tone and are less liable to its decrease after the above local hypotensive therapy.

[Changes in regional hemodynamics indices in patients with open-angle glaucoma]. / Izmenenie pokazatelei regional'noi gemodinamiki u bol'nykh otkrytougol'noi glaukomoi.

Changes in the hemodynamic parameters of the eye were examined in patients with primary open-angle glaucoma (OAG) in the well developed and far advanced stages with moderately increased (up to 32 mm Hg) and high (33 mm Hg and higher) pressure before and after surgery. Computer-aided vacuum ophthalmodynamometer was used with a sucking cup calibrated for two levels of ophthalmic tone, whose external diameter was 13 mm and funnel angle 60 degrees. A total of 59 patients (82 eyes) aged 50 to 84 years were examined, control group consisted of 18 patients (36 eyes). Mean dynamic pressure in the orbital artery and perfusion pressure were measured, and the orbital-brachial coefficient estimated. Progressive decrease of perfusion pressure was paralleled by increase of the mean dynamic pressure in the orbital artery in patients with stages Iic and IIIb OAG and by its decrease in those with stage IIIc OAG. Such changes of the hemodynamics are explained by the compensatory work of the ocular bloodflow autoregulation mechanism in the first case and its failure in the second. After regression analysis, linear equations of the relationship between changes in the mean dynamic pressure and intraocular pressure were calculated. After surgery, changes in the hemodynamic parameters were followed up for 12 months in 27 eyes with well-developed condition and for 6 months in 13 eyes with far advanced condition.