Biomedical subjects

M Araie

Publications and source records attributed to M Araie.

At least 73 records · Page 4Linked to original sources

PubMed1999

Effects of pranidipine, a new calcium antagonist, on circulation in the choroid, retina and optic nerve head.

PURPOSE: To study the effects of pranidipine, a newly developed Ca(2+)-antagonist, on tissue circulation in the optic nerve head (ONH), choroid, and retina in rabbits. METHODS: Pranidipine (5 microg/kg) or vehicle solution was injected intravenously in urethane-anesthetized rabbits and the normalized blur value (NB), a quantitative index of in vivo tissue blood velocity, was measured in the choroid and in an area of the ONH and retina free of visible surface vessels before and for 90 min after injection, using the laser speckle method. Measurements in the ONH and choroid were performed in the same albino rabbit eyes (pranidipine group, n = 10; control group, n = 10) and those in the retina in another group of Dutch rabbits (pranidipine group, n = 10; control group, n = 10). RESULTS: Between 30 and 90 min after injection, the NB in the pranidipine group increased by 24% in the ONH, 19% in the choroid, and 17% in the retina on an average compared to baseline, and was significantly different from that in the control group (P < 0.0001, ANOVA). There were no significant inter-group differences in the systemic parameters, except for a transient decrease in blood pressure in the pranidipine groups. CONCLUSIONS: Pranidipine increased blood velocity and probably blood flow in the ONH, choroid, and retina of rabbits.

Animals↗

PubMed1999

Effect of topical amosulalol on tissue circulation in the optic nerve head.

The effect of topical 0.1% amosulalol on tissue circulation in the albino rabbit optic nerve head (ONH) was investigated using a laser speckle tissue circulation analyzer. Amosulalol was administered into one eye twice daily for 20 days, and vehicle was administered into the other eye in a masked, randomized manner. Intraocular pressure (IOP) was measured every 5 days. The normalized blur value (NB), a quantitative index of tissue blood flow velocity in the ONH, was measured before treatment and 2 hours after the last instillation on day 20. The IOP was also measured at 5-day intervals. Amosulalol decreased IOP by approximately 2 mmHg in the treated eyes (P < 0.01). There was no significant difference in NB between eyes before the first instillation, whereas NB was significantly greater (by approximately 16%) in the amosulalol-treated eye than in the control eye after completion of instillations (P < 0.01). The difference between NB after completion of instillations and that before the first instillation was significantly greater in the ONH of the amosulalol-treated eye than in the contralateral control eye (P < 0.01). Twice-daily instillation of 0.1% amosulalol for 20 days induced a significant increase in tissue blood velocity in the ipsilateral ONH in albino rabbits.

Administration, Topical↗

PubMed1999

Effect of topical betaxolol on tissue circulation in the human optic nerve head.

There have been no reports to date on long-term betaxolol instillation effects on the human optic nerve head (ONH) tissue circulation. The purpose of this study was to study the effect of topical 0.5% betaxolol on tissue blood velocity in the human ONH. Using a laser-speckle tissue blood flow analyzer, normalized blur (NB; a quantitative index of tissue blood velocity) was measured every 0.125 seconds at a temporal ONH site free of visible surface vessels. Measurements were averaged for 3 cardiac cycles (NB(ONH)). For baseline comparison (day 0), recordings of bilateral NB(ONH) and intraocular pressure (IOP), blood pressure (BP) and pulse rate (PR) were recorded in healthy volunteers before, and 2, 4.5, and 7 hr after, instillation of 30 microL of betaxolol vehicle, and again on day 21; IOP was also recorded on days 7 and 14. On day 1 (the day after baseline measurements), and twice daily for 3 weeks, 30 microL of 0.5% betaxolol into one eye and 30 microL vehicle was instilled into the other in a double-blind study. Measurements as on day 0 were again recorded on day 21; IOP was also recorded on days 7 and 14. During baseline recordings, no significant changes were noted in any parameters. After administration of topical betaxolol, IOP was significantly reduced, bilaterally, with greater reduction in the betaxolol-treated eyes on day 21. Also on day 21, the NB(ONH) of the betaxolol-treated eyes was significantly higher 4.5 hr after instillation than that of the comparable baseline recording (p = 0.035 with Bonferroni's correction); BP, PR, and NB(ONH) in the eye which received only the vehicle showed little change. Tissue blood velocity in the human ONH was increased at least temporarily by instillation of topical betaxolol twice daily for 3 weeks. Although the obtained increase is small and may be clinically insignificant, the potential of betaxolol that can affect the ONH tissue circulation in humans after 21 days of instillation is thought to deserve further investigation.

Administration, Topical↗

PubMed1999

Effects of oral brovincamine on visual field damage in patients with normal-tension glaucoma with low-normal intraocular pressure.

PURPOSE: To prospectively study the effect of oral brovincamine, a relatively selective cerebral vasodilator, on further deterioration of visual field in patients with normal-tension glaucoma (NTG) with low-normal intraocular pressure (IOP). METHODS: Fifty-two patients with NTG (average age 57.7 years) with an IOP that was consistently less than 15 mmHg were randomly assigned to receive oral brovincamine (20 mg three times daily) or to an untreated control group. The groups were prospectively followed for 2 years with visual field examinations every 4 months, using the 30-2 Humphrey perimeter program. Changes in mean deviation (MD), corrected pattern standard deviation (CPSD), and total deviation (TD) at 74 test points were analyzed using regression analysis with linear mixed model. Data from one eye without media opacity of each subject were analyzed. RESULTS: There were no differences between groups in age; sex distribution; refraction; blood pressure; baseline IOP; MD, CPSD, or TD at each point. Changes in MD (standard error [SE]) during the study period were -0.778 (0.178) and -0.071 (0.195) dB/year in the control and brovincamine groups, respectively; change in the control group was significantly more negative than in the brovincamine group. Change in CPSD (SE) was 0.032 (0.015) and 0.004 (0.016) dB/year in the control and brovincamine groups, respectively. Change in the control group was significantly positive, but the intergroup difference was not significant. Change in TD was significantly negative at six test points in the control group, whereas no points showed a significant trend in the brovincamine group; the intergroup difference was significant. The average IOP was 13.2 mmHg and 13.1 mmHg in the control and brovincamine groups, respectively, and there was no significant intergroup difference. CONCLUSION: Oral brovincamine may retard further visual field deterioration in patients with NTG who have low-normal IOP.

Administration, Oral↗

PubMed1999

Effects of nilvadipine, a calcium antagonist, on rabbit ocular circulation and optic nerve head circulation in NTG subjects.

PURPOSE: To study the effects of nilvadipine, a Ca2+ antagonist, on tissue circulation in the optic nerve head (ONH), choroid, and retina in rabbits and on the ONH circulation in normal tension glaucoma (NTG) patients. METHODS: Nilvadipine (3.2 microg/kg) or vehicle solution was injected intravenously into urethane-anesthetized rabbits, and the normalized blur value (NB), a quantitative index of in vivo tissue blood velocity, was measured in the choroid and in an area of the ONH and retina free of visible surface vessels before and for 90 minutes after injection, using the laser speckle method. The effects of nilvadipine on the ONH circulation was also studied using the H2 gas clearance method in separate groups of rabbits. Oral nilvadipine (4 mg/d) or placebo was administered to NTG patients in a double-masked manner, and NB in an area of the ONH rim free of visible surface vessels was measured by the same method before and 2, 4, 8, and 12 weeks after administration. RESULTS: The NB obtained from the ONH, choroid, or retina during the experimental period was increased by approximately 10% to 25% in the nilvadipine group compared with the NB in the control group (P < 0.0001, ANOVA), although systemic condition parameters and intraocular pressure (IOP) showed no significant intergroup difference except for a transient decrease in blood pressure in the nilvadipine groups. Blood flow rate in the ONH determined by the H2 gas clearance method also showed an approximately 25% increase in the nilvadipine group. The NB in the ONH of the oral nilvadipine-treated patients was significantly increased, by approximately 20% compared with the placebo-treated patients throughout the follow-up period. No significant intergroup difference was seen in blood pressure, pulse rate, or IOP. CONCLUSIONS: Nilvadipine increased blood velocity and, probably, blood flow in the ONH, choroid, and retina of rabbits. It also increased blood velocity in the ONH of NTG patients.

Adult↗

PubMed1999

[Long-term outcome of topical cyclosporine treatment following penetrating keratoplasty].

PURPOSE: To evaluate the long-term outcome of 2% topical cyclosporine A (CsA) treatment as an adjunct to topical corticosteroid in 86 eyes after penetrating keratoplasty (PK). MATERIAL AND METHODS: The subjects were 86 eyes of 83 patients who had undergone PK and received topical CsA treatments. Ninety-seven eyes of 95 patients who had undergone PK and received similar postoperative treatments except for topical CsA treatments served as control: The clinical outcome of PK was evaluated by rates of graft survival and rejection-free graft survival using Kaplan-Meier's method and compared with the log-rank test. The patients were subdivided into high-risk and low-risk groups. The high-risk patients were those who had corneal vascularization in 2 or more quadrants of the cornea preoperatively or who received regrafting. All other patients were assigned to the low-risk group. Thirty-six eyes of the CsA group and 50 eyes of the control group were high-risk cases. RESULTS: In the high-risk patients, the rejection-free graft survival rate was 69.7% in the CsA group and 45.4% in the control group (p = 0.030). However, there was no significant difference in the graft survival rate between the two groups. In the low-risk patients, there was no significant difference in the rates of rejection-free graft survival and graft survival between the CsA and the control group. CONCLUSION: 2% topical cyclosporine is effective in reducing the risk of allograft rejection in high-risk recipients.

Administration, Topical↗

PubMed1999

[Influence of myopic disc shape in a classification program of the Heidelberg retina tomograph].

PURPOSE: We investigated the influence of myopic disc shape on the diagnostic capability of a glaucoma diagnostic software (classification program) of the Heidelberg retina tomograph (HRT). SUBJECTS: 66 eyes of 66 normal subjects and 78 eyes of 78 patients with open-angle glaucoma were studied. The criterion of glaucoma was a visual field defect appearing between Aulhorn classification stage II and stage V regardless of the maximum intraocular pressure value. METHODS: The subjects were divided into eyes with a myopic disc and those with a non-myopic disc on the basis of stereo disc fundus photographs without considering the refractive errors. Agreement between the classification program and the clinical diagnosis was evaluated by the calculation of sensitivity, specificity, and diagnostic precision, and the influence of the disc shape on HRT disc shape parameters was also evaluated. RESULTS: Sensitivity, specificity, and diagnostic precision of the classification program were 83%, 95%, and 89% in the eyes with a non-myopic disc, and 71%, 96%, and 83% in the eyes with a myopic disc, respectively. Rim volume, height variation contour, mean RNFL (retinal nerve fiber layer) thickness, and RNFL cross section area were significantly larger in the eyes with a myopic disc than in those with a non-myopic disc regardless of the clinical diagnosis. CONCLUSION: The classification program should be modified to adjust to a myopia-like disc shape in order to improve the capability of the glaucoma predictive diagnosis.

Female↗

PubMed1999

[Usefulness of gaze tracking during perimetry in glaucomatous eyes].

PURPOSE: To evaluate the usefulness of a new fixation monitoring system called gaze tracking in the perimetry of glaucomatous eyes. SUBJECTS AND METHOD: We studied the visual field of 106 eyes in 106 persons, comprising 74 eyes with open-angle glaucoma and 32 eyes with ocular hypertension. Perimetry was performed using a Humphrey Visual Field Analyzer 740/750 with a 30-2 full threshold program. We used two parameters for gaze tracking: the percentage of the time when the subject's eye deviated from the fixation target more than 3 degrees (G 3) and 6 degrees (G 6). These parameters were assessed in three groups: those with no visual field defect (group N), those with absolute visual field defect including the blind spot (group M 1), and other (group M 0). RESULT: The value of G 3 and G 6 were significantly correlated with the fixation loss in groups N and M 0 (p < 0.01). These values were not significantly correlated with the fixation loss in group M 1 (p > 0.1). When the fixation loss was less than 20%, G 3 and G 6 values were significantly higher in group M 1 than in groups N or M 0. CONCLUSION: Gaze tracking is a useful fixation monitoring system particularly in the presence of absolute visual field defect including the blind spot.

Adult↗

PubMed1999

[In vivo measurement of ocular circulation with the laser speckle method--development of apparatus and application in ophthalmological research].

We have developed an apparatus utilizing laser speckle phenomenon which can measure the peripheral circulation in the iris, choroid, retina and optic nerve head (ONH) and blood velocity through retinal vessels in the living eye non-invasively and quantitatively. A blue-component argon laser (wavelength 488 nm) was used for measurement of peripheral circulation in the retina and a diode laser (wavelength 808 nm) for measurements of peripheral circulation in the iris, posterior choroid and ONH, and measurement of centerline blood velocity through retinal vessels. A fundus camera (TRC-WT 3, Topcon) was equipped with a laser source and an image sensor where the speckle pattern from the fundus appears, and the data were analyzed with a personal computer to give a normalized blur (NB) value or a square blur rate (SBR) value, both quantitative indices of blood velocity. The NB value, whose computation requires much less time, was adopted to evaluate peripheral circulation because of non-linear correlation between the NB and actual blood velocity in the range above 20 mm/sec. The SBR value, whose computation requires a longer time, was adopted for measurement of blood velocity through retinal vessels. Measurement field in the living eye was 1.06 x 1.06 mm at its maximum and reproducibility index of the in vivo measurement in the rabbit iris, choroid, retina, and ONH was approximately 10%. When blood flow was changed by intraocular pressure (IOP) change in rabbit eyes, NB values obtained from the iris, choroid, and retina showed a significant correlation with the blood flow simultaneously determined with the colored microsphere technique in the same eye, and the NB obtained from the ONH also correlated with the blood flow determined with the H2 gas clearance method. Stepwise reduction in the ocular perfusion pressure (OPP) by stepwise increment of IOP resulted in proportional reduction in the iris- and choroid-NB. On the other hand, the retina- or ONH-NB remained almost unaltered at OPP levels above 50 mmHg, and decreased along with OPP at levels less than 50 mmHg. By monitoring NB values for 2 hours, presence or absence of autoregulatory mechanism against OPP change in the choroidal and ONH circulation was studied in rabbits. Throughout the experimental period of 2 hours, the choroidal NB was changed along with the OPP change, suggesting absence of blood flow autoregulation in this tissue. In the ONH, however, the NB returned to the baseline after its transient increase or decrease when the OPP was continuously increased or decreased, showing the presence of an autoregulatory mechanism in the ONH circulation. However, the time course of the NB resumption depended on the extent of OPP change. These results indicated that the laser speckle method can be useful in investigating the autoregulatory mechanism and processes of peripheral circulation in ocular tissues. Unilateral instillation of drugs with vasodilative activity (ifenprodil, betaxolol or nipradilol) in rabbit eyes significantly increased ONH and/or choroidal circulation. The extent in change in the ONH and/or choroidal circulation correlated with the number of doses, but not with the extent of IOP reduction, which suggested that the observed effects were attributable to the drug which penetrated locally. Intravenous administration of a Ca(2+)-antagonist (nicardipine, nilvadipine or pranidipine) significantly increased choroidal or retinal circulation in rabbits. The ONH circulation, however, was not affected by nicardipine, but affected by nilvadipine or pranidipine. Given the same effect on the ONH circulation, systemic hypotensive effect was stronger in pranidipine than in nilvadipine, which suggested that nilvadipine can be used in patients with ocular circulatory insufficiency. A modification of the laser speckle apparatus used for animal experiments was devised so that the NB or SBR values could be measured in human eyes every 0.12 sec on a real-time basis. (ABSTRACT TRUN

Adult↗

PubMed1998

Conditions for balance between lower normal pressure control and hypotony in mitomycin trabeculectomy.

BACKGROUND: Striving for low to ultra-low postoperative intraocular pressure (IOP) through filtering surgery usually increases the incidence of prolonged hypotony. Early postoperative prognostic indicators for IOP control to lower normal level and prolonged hypotony in trabeculectomy with mitomycin C were examined to determine conditions required to obtain an optimum balance between them. METHODS: Records of initial trabeculectomy with mitomycin C (0.4 mg/ml, 3 min) in 59 consecutively operated Japanese patients with primary open-angle glaucoma who had used multiple medications before operation were retrospectively analyzed. IOP control to lower normal level was defined as having failed if IOP could not be maintained below 15 mm Hg without medication. Prolonged hypotony was defined as postoperative IOP below 5 mm Hg for more than 2 months, excluding the first month. The Cox proportional hazards model was applied to identify early postoperative factors contributing to the two surgical outcomes. RESULTS: Among the factors studied, only the mean IOP on postoperative days 9-14 was significantly correlated with the surgical outcome. A receiver operating characteristic plot suggested that mean IOP of 8 mm Hg in this period would give an optimum balance between the two. CONCLUSION: IOP of 8 mm Hg 9-14 days after surgery may be advisable in patients with preoperative multiple medications in whom IOP control to lower normal level is attempted with mitomycin C trabeculectomy. Knowledge of this may be helpful in deciding when laser lysis of sutures is indicated.

Female↗

PubMed1998

In vivo measurement of iridial circulation using laser speckle phenomenon.

PURPOSE: To evaluate the use of the laser speckle phenomenon for noninvasive in vivo consecutive measurement of the iridial circulation. METHODS: A pigmented rabbit iris was illuminated using a diode laser, and the normalized blur of the resulting laser speckle pattern, NBiris, was determined as a quantitative index of blood velocity in the iridial tissue. The authors compared data on positional variation, reproducibility, and correlation to iridial blood velocity derived with this technique with the blood flow rate simultaneously determined by the microsphere technique. They also evaluated the effects on iridial circulation of ocular perfusion pressure (OPP) change, rectus muscle excisions, and instillation of topical timolol or betaxolol. RESULTS: The NBiris increased gradually from the pupil margin to the periphery; the coefficient of variation of NBiris was lowest at the center of this area. The coefficient of reproducibility of two NBiris measurements at 5-minute intervals was 8.8%; at 24-hour intervals, it was 14.1%. The NBiris correlated well with the microsphere technique measurements of blood flow rate at several intraocular pressures (IOP) (r = 0.61, P = 0.0002, n = 40) and with the comparison of preinstillation and postinstillation unoprostone (r = 0.93, P = 0.0068, n = 8). The NBiris decreased with OPP reduction, decreased temporarily after excision of the superior or inferior rectus, and showed no significant change after excision of the medial or lateral rectus. Instillation of timolol caused a significant decrease in IOP but did not significantly change the NBiris. Topically applied betaxolol decreased IOP and increased NBiris at 2.5 hours after instillation in an ipsilateral eye. CONCLUSIONS: The laser speckle method permits noninvasive, semiquantitative, consecutive measurement of the iridial circulation, with reasonable reproducibility.

Adrenergic beta-Antagonists↗

PubMed1998

[The cytotoxic effect of topical mitomycin C on the ciliary body in rabbits].

We evaluated the cytotoxic effects of mitomycin C (MMC) in rabbit eyes. A sponge soaked with MMC was placed on the bared sclera after conjunctival incision. We used four concentrations of MMC in distilled water: 0%, 0.04%, 0.1%, and 0.4%. MMC was applied to one eye only, with the fellow eye serving as control. The eyes were studied for intraocular pressure (IOP) and by fluorophotometry at 3, 7, 14, and 28 days of treatment. Eyes treated with 0.04% and 0.4% MMC were studied histologically at 3 and 28 days. All the MMC-treated eyes showed no significant changes regarding IOP (56 eyes) or fluorophotometric features (28 eyes) regarding aqueous humor dynamics and blood-aqueous barrier. Pathologic changes of the ciliary epithelium, including intracellular vacuoles and swelling of mitochondria, were more pronounced in eyes treated with 0.4% MMC than those treated with 0.04%. These changes were more manifest in areas inner to the site of application than in the opposite area. Topical application of 0.04% MMC thus showed no evident toxic effects on the function of the ciliary body and other pathological changes were minor.

Administration, Topical↗

PubMed1998

Effects of topical nipradilol, a beta-blocking agent with alpha-blocking and nitroglycerin-like activities, on aqueous humor dynamics and fundus circulation.

PURPOSE: To study the effects of nipradilol, a nonselective beta-blocker with alpha 1-blocking activity and nitroglycerin-like activity, on aqueous humor dynamics and optic nerve head (ONH) circulation in albino rabbits. METHODS: Experiments were carried out during the dark phase, in conscious rabbits conditioned to a schedule of alternating 12-hour periods of light and dark. The blood-aqueous barrier permeability and the aqueous flow rate were determined fluorophotometrically. The effect on outflow to general blood circulation and uveoscleral outflow were determined by using the fluorophotometric Diamox technique, and the effect on the uveoscleral outflow was further assessed by using the anterior chamber perfusion method. The ONH circulation was estimated by using the laser speckle method. RESULTS: Unilateral topical administration of 0.25% nipradilol solution lowered intraocular pressure (IOP) with relatively weak contralateral effects in a dose-dependent manner with a maximum reduction of 6 mm Hg and an effect duration of 6 hours. Twice-daily instillation for 14 days showed no attenuation of the effects. Single instillation of 0.25% nipradilol showed no significant effect on blood-aqueous barrier permeability and decreased aqueous flow rate in the treated eye (17%; P < 0.01) and in the contralateral eye (9%, P < 0.05). Nipradilol produced no significant effect on outflow facility to general blood circulation, whereas it substantially increased uveoscleral outflow. Twice-daily 0.25% nipradilol instillation increased ONH tissue blood velocity by 13% (P < 0.01), which was probably attributable to locally penetrating drug. CONCLUSIONS: Because of its ability to lower IOP and to increase uveoscleral outflow and optic nerve head circulation in rabbits, further studies are warranted to determine whether nipradilol has potential as an antiglaucoma agent in humans.

Administration, Topical↗

PubMed1998

[The effect of continuous and intravenous application of carteolol chloride on tissue blood flow in the rabbit optic nerve head].

The effect of systemic application of carteolol, which induces almost the same plasma carteolol level as obtained by a long-term instillation on rabbit eyes, on the tissue blood flow in the optic nerve head (ONH) was investigated in rabbits. The plasma carteolol levels in 27 rabbits which received 3-week instillation, intravenous injection (10, 20, 30 micrograms/kg), or continuous intravenous injection (2.5, 5, 20, 40, 80 micrograms/kg/hr) were measured by gas chromatography-negative-ion chemical ionization mass spectrometry. The plasma level with 3-week instillation was determined as 5.55 ng/ml and a continuous intravenous injection (5 micrograms/kg/hr) caused nearly the same plasma level. The intravenous injection of this dose significantly increased the ONH blood flow which was determined by the hydrogen clearance method, compared with controls from 30 minutes to 2 hours after the injection (n = 10). The vascular resistance in ONH was thought to be reduced because mean blood pressure and intraocular pressure (n = 6) were not significantly changed. The results suggest that the plasma carteolol level in rabbits after a long-term instillation can increase ONH blood flow due to a decreased vascular resistance.

Adrenergic beta-Antagonists↗

PubMed1997

Stereoscopic ophthalmic microendoscope system.

Technical characteristics of a new stereoscopic ophthalmic microendoscope system developed for the direct observation of intraocular structures are described herein. Our system includes a stereoscopic visualization mechanism and an image superimposing system that projects the endoscopic image into the eyepiece of the surgical microscope, allowing the surgeon to monitor 3-dimensional endoscopic and microscopic images simply by looking into the eyepiece of the surgical microscope. Stereoscopic visualization of the intraocular structure facilitates fine manipulation of the endoscope probe just above the retina or ciliary body, providing more reliable and safer control of the probe within the eye. Preliminary clinical experience has demonstrated the usefulness of this new system.

Endoscopes↗

PubMed1997

Effect of long-term topical betaxolol on tissue circulation in the iris and optic nerve head.

The effect of long-term topical betaxolol on tissue circulation in the iris and optic nerve head was studied. Twenty microliters of 0.5% betaxolol ophthalmic solution was instilled in one eye of an albino rabbit and the same amount of physiological saline in the fellow eye twice daily for 20 days. A quantitative index of tissue blood velocity, NB value, was measured in the iris (21 rabbits) and optic nerve head (31 rabbits) of both eyes before the first instillation and 2 hr after completion of instillations, using a laser speckle tissue circulation analyser of which details have been reported previously. The intraocular pressure was also measured at 5-day intervals. The intraocular pressure was lowered by 2-3 mmHg only in the betaxolol-treated eye (P < 0.01). Both in the iris and optic nerve head no significant bilateral difference in the NB was seen before the first instillation, while it was significantly greater in the betaxolol-treated than in the contralateral control eye by about 10% after completion of instillations (P < 0.02-0.05). The difference between the NB after completion of instillations and that before the first instillation was significantly greater in the betaxolol-treated eye than in the contralateral control eye both in the iris and optic nerve head (P < 0.001-0.02). Twenty-day twice daily instillation of 0.5% betaxolol caused relatively small, but significant increase in tissue blood velocity in the ipsilateral iris and optic nerve head in albino rabbits, which may have clinical implications.

Administration, Topical↗

PubMed1997

Effects of topical adrenergic agents on tissue circulation in rabbit and human optic nerve head evaluated with laser speckle tissue circulation analyzer.

The effects of topical adrenergic agents on the tissue circulation of the optic nerve head (ONH) were studied in animal and human eyes with use of a laser speckle tissue circulation analyzer. Drugs studied were nipradilol, a beta1-2-blocker with weak alpha-blocking and nitroglycerinlike activities; bunazosin, a selective alpha1-blocker; carteolol, a beta1-2-blocker with intrinsic sympathomimetic activity; and betaxolol, a selective beta1-blocker. In the animal experiment, one eye each of nine albino rabbits received 0.25% nipradilol (N = 9) twice daily for 15 days or 0.01% bunazosin (N = 10) twice daily for 20 days; the fellow eye received the vehicle of each drug in a randomized masked design. Normalized blur (NB) in an area of ONH free of visible surface vessels, a quantitative index of peripheral blood velocity in ONH, was measured under general anesthesia before treatment and 2 hours after the last instillation on the 15th or 20th day. At 15 days, intraocular pressure and NB in the nipradilol-treated eyes decreased by 4.3 mm Hg (P < 0.01) and increased by 15.9% (P < 0.01), respectively, while those in the vehicle-treated eyes showed little change. At 20 days NB in both bunazosin- and vehicle-treated eyes showed little change, while intraocular pressure decreased only in the bunazosin-treated eyes (P < 0.01). In the human volunteer experiment NB was averaged over five pulses (mean NB) in both eyes before and 1.5, 3.0 and 4.5 hours after a 30 microL instillation of the vehicle of carteolol or betaxolol to serve as a control. Intraocular pressure, blood pressure and pulse rate were also measured. One week later a 30 microL drop of 2.0% carteolol (N = 6) or 0.5% betaxolol (N = 10) was instilled in one randomly chosen eye and the vehicle for each drug in the other eye, and those parameters were measured as above in a double-masked manner. In the carteolol experiment, mean NB in both eyes was significantly higher at 3 hours than it was in the control experiment (P < 0.05), while intraocular pressure was significantly lower in both eyes and blood pressure and pulse rate showed little change. In the betaxolol experiment, intraocular pressure at 1.5 hours and blood pressure at 4.5 hours were significantly lower than those in the control experiment (P < 0.05), while mean NB and pulse rate showed little change. In summary, using the laser speckle method we found that topical nipradilol and carteolol increase ONH blood velocity in rabbits and humans, respectively. This finding suggests that some topical beta-blockers used clinically may influence the ONH tissue circulation in patients and that this method may be used in clinical situations to assess the effect of various drugs on ONH circulation.

Administration, Topical↗

PubMed1997

Effect of trabeculectomy on visual field performance in central 30 degrees field in progressive normal-tension glaucoma.

PURPOSE: The authors studied the effects of trabeculectomy on the time course of central 30 degrees visual field performances in progressive normal-tension glaucoma (NTG). METHODS: Patients with NTG who had clear ocular media and were adequate performers on the 30-2 program of Humphrey Perimeter were prospectively followed with periodic field testing. Trabeculectomy using an antimetabolite was indicated when the slope of a line fitted to the time course of the mean deviation (MD), MD slope, was significantly negative. The time courses of MD and mean of total deviations (mean TD) in four subfields, superior and inferior arcuate and superior and inferior cecocentral fields, were analyzed using the mixed linear model. RESULTS: In progressive NTG, 21 eyes of 21 cases with postoperative follow-up of 2 years or more, intraocular pressure averaged 16 mmHg, MD averaged -13.5 dB, and MD slope averaged -1.48 dB/year preoperatively; 2 years after surgery, they averaged 9.2 mmHg, -13.6 dB, and +0.13 dB/year, respectively. Trabeculectomy had a significant beneficial effect on the time course of MD and mean TD in the superior and inferior arcuate and superior cecocentral fields, which showed significant preoperative deterioration. The mean TD in the inferior cecocentral field showed no significant time change during the period studied. CONCLUSION: For patients with NTG in whom the MD slope is significantly negative, trabeculectomy may have beneficial and diffuse effects on further deterioration of the visual field.

Antimetabolites↗