Biomedical subjects

Victor E Malinovsky

Publications and source records attributed to Victor E Malinovsky.

3 recordsLinked to original sources

PubMed2006

A comparative analysis of the effects of the fixed combination of timolol and dorzolamide versus latanoprost plus timolol on ocular hemodynamics and visual function in patients with primary open-angle glaucoma.

AIMS: The aim of this study was to assess the effects of fixed combination of timolol and dorzolamide and latanoprost plus timolol on retinal, choroidal, and retrobulbar hemodynamics and visual function in primary open-angle glaucoma (OAG) subjects. METHODS: Sixteen (16) OAG patients (age, 63.5 +/- 10.8 years; 9 male) were evaluated in a randomized, crossover, double-blind study design after 4 weeks of treatment of latanoprost with timolol and fixed combination of timolol and dorzolamide. After randomization, 9 right eyes and 7 left eyes were included in the hemodynamic portion of the study. Measurements included: adverse events check, visual acuity, contrast sensitivity, blood pressure, heart rate, intraocular pressure (IOP), and fundus examination. Ocular blood flow was assessed using confocal scanning laser Doppler flowmetry, color Doppler imaging, and scanning laser ophthalmoscopy. RESULTS: Both therapies were effective at lowering IOP, whereas there was no statistically significant difference between latanoprost plus timolol and the fixed combination of timolol and dorzolamide (13.9% and 12.2% reduction, respectively; P = 0.5533). Fixed combination of timolol and dorzolamide significantly increased central retinal artery end diastolic blood flow velocity (P = 0.0168) and lowered resistance to flow (P = 0.0279). Temporal posterior ciliary artery peak systolic and end diastolic velocities were significantly increased with the fixed combination of timolol and dorzolamide (P = 0.0125 and 0.0238, respectively). Latanoprost plus timolol had no significant effects on ocular blood flow during 4 weeks of treatment. There were no statistically significant differences in adverse events, blood pressure, heart rate, visual acuity, contrast sensitivity scanning laser ophthalmoscopy, or Heidelberg Retinal Flowmeter for any treatment period. CONCLUSIONS: Fixed combination of timolol and dorzolamide therapy might increase blood flow in OAG patients while attaining a similar IOP reduction compared to latanoprost plus timolol. Visual function, however, was not different in this short-term comparison between the two treatments.

Adrenergic beta-Antagonists↗

PubMed2006

Multifocal pattern electroretinogram: cellular origins and clinical implications.

PURPOSES: The purposes of this article are to gain insight into the cellular origins of the multifocal pattern electroretinogram (mPERG) and evaluate its potential for clinical use. METHODS: mPERGs were recorded from four anesthetized monkeys before and after pharmacologic blockade of light-driven activity of inner-retinal neurons and from 55 normal human subjects (19-91 years) and six patients with glaucoma (43-77 years of age). Stimuli consisted of counterphase-modulated black and white triangles organized in 61-scaled hexagons with mean luminance 100 cd/m2 and 100% contrast. The stimulus array subtended 31 degrees vertically and 37 degrees horizontally at 48 cm. The amplifier cutoff frequencies were 3 and 100 Hz. Responses were grouped as quadrants and the first slice of the second-order kernel was analyzed. RESULTS: The mPERG responses of monkeys and humans were similar. In the monkey responses, there was an early positive potential (P1) around 25 ms and a later positive potential (P2) found selectively in the nasal field quadrants around 31 ms. These responses were seen around 22 and 36 ms in the human responses. After blockade of inner-retinal activity in monkeys, P1 amplitude was greatly reduced at all retinal locations and P2 was eliminated. P1 and P2 amplitudes were significantly reduced in the glaucomatous eyes relative to amplitudes of age-matched controls. Reductions in the amplitudes of P1 and P2 could easily discriminate between glaucomatous visual field quadrants with and without behavioral sensitivity losses. However, these alterations are likely to reflect diffuse losses. CONCLUSIONS: mPERG responses contain prominent contributions from inner-retinal neurons that can be reduced in glaucomatous eyes. These findings raise the possibility that the mPERG could be potentially useful in the objective estimation of neural damage in glaucoma. However, further refinement of recording techniques will be required if the mPERG is to be used to detect focal damage.

Adult↗

PubMed2002

Proton therapy for exudative age-related macular degeneration: a randomized, sham-controlled clinical trial.

PURPOSE: To examine the effect of proton beam irradiation on subfoveal choroidal neovascular membranes (CNVM) associated with age-related macular degeneration (AMD).Randomized, prospective, sham-controlled, double-masked treatment trial. METHODS: Thirty-seven subjects with subfoveal CNVM due to AMD were randomly assigned to 16-Gy proton irradiation delivered in two fractions 24 hours apart or to sham control treatment. Recruitment was halted at 37 subjects for ethical reasons regarding randomization to sham treatment when Food and Drug Administration approval of Visudyne was anticipated. RESULTS: Proton irradiation was associated with a trend toward stabilization of visual acuity, but this association did not reach statistical significance. No correlations were found within the fluorescein angiography data, including greatest linear dimension of CNVM total size, area of active leakage, area of associated subretinal hemorrhage, and intensity. CONCLUSIONS: With the acceptance of photodynamic therapy, future studies will require more complex design and larger sample size to determine whether radiation can play either a primary or adjunctive role in treating these lesions.

Aged↗