Biomedical subjects

Y Kitazawa

Publications and source records attributed to Y Kitazawa.

At least 73 records · Page 4Linked to original sources

PubMed1998

A frequency-doubling perimetric study in normal-tension glaucoma with hemifield defect.

PURPOSE: The authors prospectively compare perimetric results obtained by conventional differential light sensitivity (DLS) perimetry and frequency-doubling perimetry (FDP) in normal-tension glaucoma (NTG) with a hemifield visual field defect, assuming that some of these eyes already have early glaucomatous changes in the "intact" hemifield. METHODS: Eleven eyes of 11 patients with NTG who met the enrollment criteria were studied. Seven eyes had an upper hemifield defect and four had a lower defect, determined by DLS with a Humphrey Field Analyzer (Zeiss-Humphrey, Inc., San Leandro, CA, U.S.A.). Frequency-doubling perimetry and DLS perimetry were conducted less than 7 days apart. To quantitatively detect nerve fiber layer defect (NFLD), scanning laser ophthalmoscopy was also performed. RESULTS: Of the 11 intact hemifields, seven showed NFLD. Of the seven, six also showed visual field defects by FDP. Of the four eyes without NFLD, two showed no defects in the intact hemifield by FDP. The threshold values of FDP and DLS perimetry did not significantly correlate in either the intact or the defective hemifields, or in the total field. The average test time of FDP was approximately 6 minutes. CONCLUSIONS: Frequency-doubling perimetry may detect early glaucomatous visual field defects.

Adult↗

PubMed1998

[Association between watershed zone and visual field defect in normal tension glaucoma].

In order to evaluate the association between the watershed zone and glaucomatous optic damage, we performed indocyanine green fluorescence angiography with a scanning laser ophthalmoscope in 54 eyes of 27 patients with normal tension glaucoma. The visual field indices were measured with a Humphrey Field Analyzer. We identified 8 eyes (14.8%) of 7 patients with a watershed zone not including the optic nerve head (type I), 32 eyes (59.3%) of 20 patients with the zone partially including the optic nerve head (type II), and 14 eyes (26.0%) of 10 patients with the zone including the optic nerve head (type III). Of the total of 27 patients, 10 patients (37.0%) had different types in each eye. In these patients, the mean deviation (MD) of visual field indices was worse in the eye with the watershed zone which included a larger part of the optic disc than in the contralateral eye (p < 0.05). Conversely, the eye with worse MD than the contralateral eye had a watershed zone which included a larger part of the optic disc than the other eye (p < 0.05). The location of watershed zone appeared to influence the progression of the visual field defect.

Adult↗

PubMed1998

Transscleral cyclophotocoagulation with the diode laser for neovascular glaucoma.

BACKGROUND AND OBJECTIVE: To compare the outcome of transscleral cyclophotocoagulation (TSCPC) using a diode laser with that of TSCPC using an Nd:YAG laser in neovascular glaucoma. PATIENTS AND METHODS: The surgical outcome of diode laser TSCPC was retrospectively compared with that of free-running mode Nd:YAG laser (FR-YAG) TSCPC and continuous-wave mode Nd:YAG laser (CW-YAG) TSCPC. Twenty-one eyes of 21 patients in the diode laser group, 9 eyes of 9 patients in the FR-YAG group, and 9 eyes of 9 patients in the CW-YAG group were treated. RESULTS: The Kaplan-Meier life-table analysis revealed that the probability (mean +/- standard error) of successful intraocular pressure control with diode laser TSCPC at 3 years postoperatively was 47.2 +/- 12.6% per operation and 55.9 +/- 16.3% per eye. Compared with the CW-YAG TSCPC, the diode laser TSCPC had a significantly higher probability of success throughout the follow-up period. Diode laser TSCPC was associated with improvements or preservation of visual acuity in 16 of 21 eyes (76%), and was the best of the three laser sources. Postoperative complications were minor following diode laser TSCPC. CONCLUSION: Diode laser TSCPC appears to be as effective as FR-YAG TSCPC and better than CW-YAG TSCPC for treating neovascular glaucoma.

Ciliary Body↗

PubMed1998

The effect of nilvadipine, a calcium-channel blocker, on the hemodynamics of retrobulbar vessels in normal-tension glaucoma.

PURPOSE: To investigate the effect of nilvadipine, a calcium-channel blocker, on the hemodynamics of retrobulbar vessels in normal-tension glaucoma. METHODS: Twenty-five patients who prospectively met the enrollment criteria underwent color Doppler imaging of the retrobulbar vessels before and after receiving 4 weeks of treatment with 2 mg oral nilvadipine twice daily. RESULTS: Nilvadipine significantly increased the end-diastolic velocity in the central retinal artery and a short posterior ciliary artery. It significantly reduced the resistance index in the central retinal artery and posterior ciliary arteries, but not in the ophthalmic artery. The calculated ocular perfusion pressure was not affected. CONCLUSION: Oral nilvadipine reduces vascular resistance in distal retrobulbar arteries in normal-tension glaucoma without affecting more proximal blood vessels. Therefore, nilvadipine may have a beneficial effect on the hemodynamics of retrobulbar vessels in normal-tension glaucoma.

Administration, Oral↗

PubMed1998

Correlation of the peripapillary atrophy area with optic disc cupping and disc hemorrhage.

PURPOSE: To investigate the association of the peripapillary atrophy area with disc cupping area and disc hemorrhage in subjects who underwent ocular examination as part of a routine physical examination. METHODS: We reviewed plain color fundus photographs taken of 12,140 eyes of 6,070 subjects as part of a routine health examination. The refractive error in these eyes was not known. Using a computerized image analysis system, we measured the area of peripapillary atrophy (zone beta), the optic disc, and optic disc cupping by means of planimetry in 8,842 eyes of 4,421 subjects with fundus images of good quality. RESULTS: The ratio of cup area to disc area was significantly greater in eyes with peripapillary atrophy (0.36 + 0.09) than in eyes without peripapillary atrophy (0.34 + 0.07), and the ratio of peripapillary atrophy area to disc area was significantly greater in eyes with disc hemorrhage (0.26 + 0.34) than in those without disc hemorrhage (0.09 + 0.18). Moreover, in eyes with peripapillary atrophy, the ratio of cup area to disc area was significantly larger in eyes with disc hemorrhage (0.48 + 0.08) than in those without disc hemorrhage (0.36 + 0.09). These results remained statistically unchanged even after "glaucomatous" eyes were excluded from the study. CONCLUSION: Peripapillary atrophy appears to be associated with a higher degree of cupping of the optic disc and disc hemorrhage, and the results suggest an association between peripapillary atrophy and glaucomatous optic neuropathy.

Female↗

PubMed1998

Retinal nerve fiber layer thickness within the area of apparently normal visual field in normal-tension glaucoma with hemifield defect.

PURPOSE: To evaluate changes in nerve fiber layer (NFL) thickness in areas with apparently normal retinal sensitivity in eyes with normal-tension glaucoma (NTG) with hemifield dominant visual field defects. METHODS: The prospective clinical study consisted of 17 eyes from 17 patients with NTG in whom superior or inferior hemifield dominant defects based on the Humphrey visual field of central 30 degrees were present, and 10 normal eyes from 10 control subjects matched in age and refractive error. The retinal NFL thickness was evaluated with a scanning laser polarimeter. Mean NFL thickness measurements in the defined ring in four quadrants (superior, inferior, nasal, and temporal) were obtained. To facilitate visual field and NFL thickness correspondence, the total deviation (TD) plot of the visual field was divided into four 90 degrees quadrants, using Wirtschafter's scheme to match the four quadrants examined by laser polarimetry. RESULTS: The mean NFL thickness in the unaffected quadrant, i.e., the quadrant within the area corresponding to the hemifield with apparently normal visual field in eyes with NTG, was significantly thinner than the average NFL thickness of the superior and inferior quadrants in the normal eyes. In eyes with NTG, the NFL thickness in the affected quadrant also was significantly thinner than that in the unaffected quadrant. In the unaffected quadrant, visual field TD (the sum of the TD values within this quadrant) showed a significant correlation with the ratio of NFL thickness in the unaffected quadrant to that in the nasal quadrant. CONCLUSION: Early changes in the retinal nerve fiber layer may already exist even in the unaffected area of the visual field in eyes with NTG with hemifield dominant visual field defects.

Adult↗

PubMed1998

[Evaluation of the Swedish interactive thresholding algorithm, a new thresholding algorithm, of the Humphrey Field Analyzer in glaucoma patients].

The Swedish interactive thresholding algorithm (SITA) is a new thresholding algorithm that aims to obtain the visual fields of the same quality in a shorter examination time than the conventional up-and-down method. We investigated the correlation between the threshold values obtained by SITA and the conventional thresholding algorithm in 30 glaucoma patients. The results of two types of SITA, i.e., SITA accurate and SITA fast, showed a significant correlation with those of the conventional method (r = 0.855, p < 0.0001 and r = 0.833, p < 0.0001, respectively). There was no statistical relation between the mean deviation (MD) of the conventional method and the difference between MD values of the conventional method, and SITA accurate and SITA fast. The examination time of SITA accurate and SITA fast was 50% and 31% shorter, respectively, than that of the conventional method. The difference in threshold of each test point in the conventional and SITA methods was minor except in one with a deep relative defect. These results indicate that SITA can be useful for detecting glaucomatous visual field defects in a shorter time.

Algorithms↗

PubMed1998

Clinical factors associated with progression of normal-tension glaucoma.

PURPOSE: To investigate clinical factors associated with the progression of visual field loss in normal-tension glaucoma (NTG). METHODS: One hundred and ten patients with NTG whose cases were followed for more than 2 years were retrospectively analyzed with the Kaplan-Meier life table method and the Cox proportional hazards model. Several clinical factors were investigated to find a possible association with progression of glaucomatous visual field defined by two different definitions: one by mean deviation change and the other by pointwise comparison. RESULTS: The Cox proportional hazards model indicated that change in the visual field was significantly associated with treatment with calcium channel blockers, recovery rate from a cold recovery test, systolic blood pressure, disc hemorrhage, corrected pattern standard deviation, mean deviation, and fluctuation of intraocular pressure (IOP) at a 24-hour phasing. The probability of nonprogression of visual field loss was significantly higher for patients taking calcium channel blockers than for control subjects by either definition of visual field progression. CONCLUSION: Factors other than IOP, including the use of calcium channel blockers, are associated with the outcome of visual field loss in NTG.

Adult↗

PubMed1997

Clinical evaluation of UF-021 (Rescula; isopropyl unoprostone).

We have reviewed two Phase III clinical studies of isopropyl unoprostone conducted in Japan: a 12-week comparative study of 0.12% isopropyl unoprostone and 0.5% timolol, and a 52-week administration of two concentrations of isopropyl unoprostone in ocular hypertensive and primary open-angle glaucoma patients. These studies showed a similar ocular hypotensive effect of 0.12% isopropyl unoprostone to 0.5% timolol and a sustained ocular hypotensive effect of the drug for up to one year. Adverse reactions of isopropyl unoprostone were minor and similar to those of timolol. No pigmentary changes of the irides were noticed. In view of these results, isopropyl unoprostone seems to be a useful antiglaucoma medication.

Administration, Topical↗

PubMed1997

The efficacy of cooling on excimer laser photorefractive keratectomy in the rabbit eye.

We cooled the surface of the cornea to reduce the thermal damage by the excimer laser ablation and referred to this method as "cooling photorefractive keratectomy" (cooling PRK). We performed conventional PRK and cooling PRK on rabbits' eyes and measured the thermal change during laser ablation. We also examined the degree of subepithelial haze and the tissues with a light microscope and an electron microscope. Normal corneal temperature of live rabbit corneas was about 32 degrees C and it rose to 41 degrees C after 300 laser shots. However, when we cooled the rabbit corneas to 24 degrees C with continuous irrigation of chilled BSS PLUS solution before laser ablation, the temperature rose only to 34 degrees C after the same ablation. Slit-lamp evaluation showed that more severe corneal haze occurred with the conventional PRK procedure. At 2 weeks postoperatively, the mean haze score was 1.77 +/- 0.87 in the conventional PRK and 0.87 +/- 0.38 in the cooling PRK (P < 0.01). Light-microscopy examination showed epithelial hyperplasia and fibroblasts, type III collagen, and heat shock protein-70 in the subepithelium of corneas with conventional PRK procedure than with cooling PRK. Under the electron microscope, more disruption of the layers of fibroblasts and collagen fibrils was observed in the conventional PRK procedure than that of the cooling PRK. In conclusion, the cooling of the corneal surface in PRK effectively reduces tissue damage related to subepithelial haze and may enable us to reduce the degree of myopic regression.

Animals↗

PubMed1997

The associations of optic disc hemorrhage with retinal nerve fiber layer defect and peripapillary atrophy in normal-tension glaucoma.

OBJECTIVE: The purpose of the study is to elucidate a topographic correlation between optic disc hemorrhages and retinal nerve fiber layer defects as well as peripapillary atrophy in normal-tension glaucoma (NTG). DESIGN: The authors prospectively studied the relation between the precise locations of disc hemorrhages and retinal nerve fiber layer defects in the first part of the study. The authors also compared morphometrically the peripapillary atrophy and the optic disc in eyes with disc hemorrhage with eyes without a history of disc hemorrhage in age-matched patients in the second part of the study. PARTICIPANTS: In part 1, 42 patients with NTG (male/female = 11/31; age, 56.8 +/- 14.2 years) in whom new disc hemorrhages developed were enrolled. In part 2, 51 randomly selected age-matched patients with NTG without a history of disc hemorrhage (male/female = 16/35; age, 55.7 +/- 12.5) were examined. MAIN OUTCOME MEASURE: In part 1, retinal nerve fiber layer defects were observed by scanning laser ophthalmoscopy using an argon-blue laser. In part 2, the area, angular extent, and radial extent of zone beta of peripapillary atrophy and the structural parameters of optic disc were measured by scanning laser tomography using a diode laser. RESULTS: In part 1, the authors detected 64 disc hemorrhages in 48 eyes of 42 patients; retinal nerve fiber layer defects were shown in 47 (97.9%) of 48 eyes by scanning laser ophthalmoscopy. Of 64 disc hemorrhages, 51 (79.7%) coincided with retinal nerve fiber layer defects in location. These 51 hemorrhages were present on the border (41.2%) or adjacent to the border (58.8%) between the retinal nerve fiber layer defect and the apparently healthy-looking retinal nerve fiber layer. In part 2, the prevalence, area, angular extent of zone beta, and ratio of zone beta area to disc area were significantly greater in the disc hemorrhage group than in the nonhemorrhage group, even though there were no significant differences in disc parameters between the two groups. CONCLUSIONS: Disc hemorrhage is associated closely with retinal nerve fiber layer defect in location and the size of peripapillary atrophy in NTG.

Adult↗

PubMed1997

High-pass resolution perimetry and a Humphrey Field Analyzer as indicators of glaucomatous optic disc abnormalities. A comparative study.

BACKGROUND: The "neural capacity (NC)" of high-pass resolution perimetry (HRP) may be correlated to the neuroretinal rim area of the optic disc. The authors compared HRP with conventional differential light sensitivity (DLS) perimetry in terms of correlation with glaucomatous optic disc changes. METHODS: Thirty-seven eyes of 37 normal-tension glaucoma (NTG) patients were examined. The authors used an Ophthimus system for HRP and a Humphrey Field Analyzer (HFA) for DLS perimetry. The total rim area and the area of temporal, superior, nasal, and inferior quadrants were determined using a confocal laser tomographic scanner. Quadrant NC (QNC) was calculated using the resolution thresholds corresponding to a given quadrant. Quadrant mean deviation (QMD) was calculated from the total deviations of HFA. RESULTS: In all eyes, NC and MD showed significant correlations with total rim area (Spearman rank correlation coefficient [rs] = 0.375, P < 0.05 for NC; rs = 0.336, P < 0.05 for MD). A significant correlation was observed in 21 eyes with early visual field changes (rs = 0.469, P < 0.05), but not in 16 eyes with advanced visual field changes. Both QNC and QMD showed significant correlations with inferior rim area (rs = 0.575, P < 0.01 for QNC; rs = 0.431, P < 0.01 for QMD). However, no significant correlations were found between QNC or QMD and superior rim area. CONCLUSIONS: The NC may relate to glaucomatous optic disc changes better than does MD in NTG, especially in eyes with early-stage visual field changes.

Adult↗

PubMed1997

The potential systemic effect of topically applied beta-blockers in glaucoma therapy.

Although topical beta-blockers are generally tolerated, they can produce significant systemic side effects. The systemic side effects of nonselective beta-blockers (eg, timolol, carteolol) are primarily related to the cardiovascular (beta 1-adrenergic) and respiratory (beta 2-adrenergic) systems. Carteolol has intrinsic sympathomimetic activity, which theoretically reduces the risk of adverse effects through beta blockade. It has been reported that topical timolol and carteolol unfavorably alter the lipid profile and that the effects of carteolol are less pronounced than those of timolol. Topical beta-blockers are associated with systemic events, not only acting by themselves, but also interacting with other drugs (eg, quinidine) administered orally or intravenously. To reduce systemic absorption and adverse effects, new preparations of beta-blockers, such as timolol gellan, have been developed. We should always bear in mind the potential systemic effects of topically applied beta-blockers in glaucoma therapy.

Administration, Topical↗

PubMed1997

A new scoring system for comparing the results of high-pass resolution perimetry and differential light sensitivity perimetry in glaucoma patients.

Using a new standard, we compared the visual field defects detected by high-pass resolution perimetry (HRP) and differential light sensitivity (DLS) perimetry in 61 eyes of 61 open-angle glaucoma patients. Abnormal test points were determined using probability plot analysis of HRP and total deviation probability maps of the Humphrey Field Analyzer. To evaluate the agreement between the two tests, we developed a new scoring system. Thirty-three eyes, 23 eyes, and 5 eyes had good, fair, and poor agreement, respectively. In relation to Aulhorn's stage classification, the more advanced the glaucomatous stage, the more increased the percentages of good agreement. These results suggest that the distribution and severity of visual field defects demonstrated by HRP agree closely with those found using DLS perimetry in glaucomatous eyes, especially those with advanced visual field changes.

Adolescent↗

PubMed1997

Mitomycin C dissolved in a reversible thermosetting gel: target tissue concentrations in the rabbit eye.

AIMS: To determine whether a new, reversible thermosetting gel enhances mitomycin C transfer to target ocular tissues in the rabbit eye. METHODS: A 0.1 ml solution of mitomycin C containing 0.22 microgram, 2.9 micrograms, or 28 micrograms of the agent dissolved in a reversible thermosetting gel consisting of methylcellulose, citric acid, and polyethylene glycol was injected subconjunctivally in 30 New Zealand albino rabbits. Scleral and conjunctival tissues were excised at 0.5, 1, 2, 4, or 24 hours after the injection and mitomycin C concentrations in these tissues were determined by high performance liquid chromatography. The concentration over time was approximated to a single exponential curve, and initial mitomycin C concentrations, time constants, and half life values were determined. Finally, the areas under the curves (AUCs) between 0.5 and 24 hours were calculated. RESULTS: The mitomycin C concentrations in the target tissues were dose dependent and decreased rapidly over 24 hours. Both the initial mitomycin C concentrations as well as AUCs in these eyes treated with mitomycin C, dissolved in a reversible thermosetting gel, were higher than those in eyes treated similarly in a previous study in which the gel was not used. CONCLUSION: Applied subconjunctivally in the rabbit eye, mitomycin C dissolved in the reversible thermosetting gel enhanced transfer of the agent to the sclera and the conjunctiva.

Animals↗

PubMed1997

Incidence of delayed onset infection after trabeculectomy with adjunctive mitomycin C or 5-fluorouracil treatment.

AIMS/BACKGROUND: The introduction of the adjunctive use of antiproliferatives to trabeculectomy has greatly improved the success rate of this operation. Trabeculectomy with antiproliferative treatment, however, is usually associated with a cystic and thin walled filtering bleb, which may be more susceptible to infection. The objective of this study was to evaluate the incidence, clinical findings, and risk factors of delayed onset, bleb related infection after trabeculectomy with adjunctive mitomycin C (MMC) or 5-fluorouracil (5-FU) treatment. METHODS: The records of 632 glaucoma patients who underwent 966 trabeculectomies, with and without the use of adjunctive MMC or 5-FU treatment, between January 1985 and February 1995 were analysed. The mean follow up period was 3.5 (2.4) years (range 0.1 to 11.2 years). The mean patient age was 54.8 (18.8) years (range 0 to 88 years). RESULTS: Bleb related infection occurred in one of 76 trabeculectomies that did not receive antiproliferatives (1.3%), three of 228 treated with 5-FU (1.3%) trabeculectomies, and seven of 662 treated with MMC (1.1%). Five eyes developed blebitis; six eyes developed endophthalmitis. Bleb related infection developed an average of 3.1 (1.6) (range 0.4 to 6.0) years after trabeculectomy. All eyes had avascular or hypovascular blebs that were cystic in shape before infection and all eyes had reduced intraocular pressure. Early wound leaks and chronic, intermittent bleb leaks were identified to be risk factors for the bleb related infection. CONCLUSION: The incidence of delayed onset, bleb related infection after trabeculectomy with antiproliferative treatment is similar to that after trabeculectomy without antiproliferatives.

Adolescent↗

PubMed1997

Appositional angle closure in eyes with narrow angles: an ultrasound biomicroscopic study.

PURPOSE: To demonstrate appositional angle closure using ultrasound biomicroscopy under dark room conditions, to investigate patterns of appositional closure, and to correlate those patterns with the angle topology in eyes with narrow angles. METHODS: Forty-six eyes that met the study criteria, from 46 individuals, were examined by ultrasound biomicroscopy under dark room and illuminated conditions. RESULTS: In 40 of the 46 eyes (87.0%), appositional closure was identified by ultrasound biomicroscopy. Two distinct patterns of angle closure were seen: type B, in which closure starts from the bottom of the angle, and type S, in which closure starts in the vicinity of Schwalbe's line. In type B, the iris root was located closure to the chamber angle than in type S. CONCLUSIONS: Ultrasound biomicroscopy performed under dark room conditions is a useful technique for identifying appositional angle closure in eyes with narrow angles. The topology of the iris root is related to the pattern of the appositional angle closure.

Adult↗

PubMed1997

Use of antifibrosis agents and glaucoma drainage devices in the American and Japanese Glaucoma Societies.

PURPOSE: To investigate practice patterns among glaucoma subspecialists in the American Glaucoma Society (AGS) and the Japanese Glaucoma Society (JGS), regarding use of antifibrosis agents and glaucoma drainage devices. METHODS: An anonymous survey incorporating 10 clinical situations was mailed to all AGS and JGS members in December 1995. RESULTS: Half of the AGS (105 of 210), and JGS (25 of 50) members returned surveys. Most respondents (51-87%) preferred trabeculectomy with adjunctive mitomycin for all 10 clinical situations. Mitomycin concentrations varied from 0.1 to 0.8 mg/ml (range of means for 10 situations 0.31-0.39 mg/ml) and intraoperative application times ranged from 5 s to 7 min (range of means for 10 situations 2.5-4.6 min). Preferences for either no antifibrosis agent (up to 39%) or 5-fluorouracil (up to 29%) were highest in primary trabeculectomy. Thirty-seven percent to 64% of AGS members used glaucoma drainage devices, especially after complicated postsurgical glaucomas (after penetrating keratoplasty, scleral buckling, or pars plana vitrectomy) and in neovascular glaucoma, but few JGS members used them. Large differences between university- and private practice-based AGS members were found only in mitomycin use for primary trabeculectomy (33% vs. 52%, respectively; p = 0.07) and for complicated postsurgical glaucomas (46% vs. 70%, respectively; p = 0.03). CONCLUSIONS: Trabeculectomy with mitomycin was the preferred surgical procedure among AGS and JGS members in the clinical situations surveyed. Mitomycin concentration and time of application varied widely. Many respondents used 5-fluorouracil or no antimetabolite in primary trabeculectomy. Glaucoma drainage devices were widely used for complicated glaucomas in the United States.

Chemotherapy, Adjuvant↗