Biomedical subjects

E Onda

Publications and source records attributed to E Onda.

13 recordsLinked to original sources

PubMed1999

Disc hemorrhage and peripapillary atrophy in apparently healthy subjects.

PURPOSE: We estimated the prevalence of disc hemorrhage and peripapillary atrophy in apparently healthy subjects. METHODS: We reviewed consecutive plain color fundus photographs of 12,140 eyes of 6,070 subjects (male/female=4,079/1,991) who visited a health consultation center. RESULTS: We analyzed 11,934 eyes of 5,967 subjects with good quality of photographs. Disc hemorrhage was found in 36 eyes of 35 subjects (0.6%). The prevalence of disc hemorrhage was significantly greater in women 60 years of age or older (Fisher's exact test, p=0.0004). The prevalence of peripapillary atrophy (zone Beta, zone Alpha), and suspected glaucomatous excavation in eyes with disc hemorrhage was 66.7%, 86.1% and 25.0%, respectively, and significantly greater than that (29.1%, 52.9% and 1.7%) in eyes without disc hemorrhage (Fisher's exact test, p<0.0001). CONCLUSIONS: Disc hemorrhage is more frequent in women over 60 years of age and is significantly associated with peripapillary atrophy in otherwise apparently healthy Japanese people.

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

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↗

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↗

PubMed1996

In vivo detection of perineural circular arterial anastomosis (circle of Zinn-Haller) in a patient with large peripapillary chorioretinal atrophy.

PURPOSE: In vivo visualization of perineural circular arterial anastomosis (circle of Zinn-Haller) has been considered impossible because of the arterial circle's location in the sclera. We investigated whether the circle of Zinn-Haller could be detected in a glaucoma patient who had a large area of temporal peripapillary chorioretinal atrophy. METHODS: We performed both scanning laser Doppler flowmetry and indocyanine green angiography with a scanning laser ophthalmoscope in the same patient. RESULTS: In the area of peripapillary atrophy, a circumferential vascular loop consistent with a portion of the circle of Zinn-Haller could be detected by the two imaging methods. CONCLUSION: The circle of Zinn-Haller can be visualized in vivo because of the peripapillary atrophy.

Arteries↗

PubMed1996

The effects of intravitreally injected endothelin-1 on the iris-ciliary body microvasculature in rabbits.

PURPOSE: We previously reported that intravitreal injection of 0.5 microg of endothelin-1 (ET-1) caused both a sustained reduction of intraocular pressure (IOP) and decreased aqueous production in the rabbit eye. On the theory that these effects might have resulted from a sustained reduction of blood flow to the ciliary body due to ET-1-mediated vasoconstriction, in the present study we attempted to determine if ET-1 causes any changes in the vascular caliber of the iris-ciliary body. METHODS: ET-1 solution (0.5 microg) was injected into the vitreous of one eye of each of 10 albino rabbits; the same amount of vehicle was injected into the contralateral eyes. One h following these injections in five of the rabbits and 24 h following them in the other five rabbits, ocular microvascular castings were obtained under controlled physiologic conditions, and the amount of vasoconstriction of the arterioles branching from the major arterial circle of the iris (MAC) and supplying the iris-ciliary body was measured by a scanning electron microscope and expressed as a percentage. RESULTS: The ET-1 caused a statistically significant focal vasoconstriction in the treated eyes as compared with the contralateral, control eyes (9.9% at 1 h and 6.2% at 24 h; both P = . 0001). CONCLUSIONS: Intravitreally injected ET-1 caused statistically significant, but only mild vasoconstriction of the arterioles supplying the ciliary processes.

Animals↗

PubMed1996

Relationship of nerve fiber layer defects and parafoveal visual field defects in glaucomatous eyes.

To evaluate the relationship between nerve fiber layer defects (NFLD) and parafoveal visual field defects in glaucomatous eyes, 23 eyes of 20 patients with open-angle glaucoma were studied by scanning laser ophthalmoscope (SLO). Only eyes in which the NFLD reached the temporal raphe in either hemisphere were used. We defined three topographic parameters of NFLD: 1) the angle (theta, degrees) of line 'A' from the optic disc center to the foveal pit, and line 'B' from the disc center to a point of the NFLD at the disc edge nearest line 'A'; 2) a horizontal distance (D1, mm) along the temporal raphe between the foveal pit and the internal edge of the NFLD; and 3) a vertical distance (D2, mm) between the foveal pit and either the superior or inferior internal edge of the NFLD. We defined the nearest defect location (in degrees from the fovea) as the nearest location with sensitivity loss of at least 6 dB (Humphrey visual field program 10-2). A highly significant correlation was found between each of the NFLD parameters and the nearest defect location (P < 0.001). The NFLD parameters we defined may be helpful for evaluating parafoveal visual function in glaucoma.

Adult↗

PubMed1995

Microvasculature of the human optic nerve.

PURPOSE: Methyl methacrylate vascular corrosion casting techniques were used to examine the normal anterior optic nerve microvasculature in 18 human eye bank eyes. METHODS: Selective cannulation of the central retinal artery, the short posterior ciliary arteries, or both, allowed the methyl methacrylate to be injected into the anterior optic nerve circulation. Preflushing with tissue plasminogen activator greatly enhanced the filling of the fine microvasculature by dissolving the intraluminal clots. RESULTS: The superficial nerve fiber layer of the optic nerve received its primary blood supply from the central retinal artery. In 11 of 13 eyes injected with methyl methacrylate through the short posterior ciliary arteries, there was a perineural, circular arterial anastomosis (circle of Zinn-Haller) at the scleral level. Branches from this circle penetrated the optic nerve to supply the prelaminar and laminar regions and the peripapillary choroid. In the two eyes without this arterial circle, direct branches from the short posterior ciliary arteries supplied the anterior optic nerve. The venous drainage of the anterior optic nerve was almost entirely through the central retinal vein and its tributaries. CONCLUSIONS: This study demonstrates that the main arterial vascular supply to the anterior optic nerve is from the short posterior ciliary arteries. The contribution of the peripapillary choroid to the anterior optic nerve is minimal in comparison to the direct contribution from the short posterior ciliary arteries.

Arteries↗

PubMed1995

An in vivo model of chronic optic nerve ischemia: the dose-dependent effects of endothelin-1 on the optic nerve microvasculature.

The purpose of this study was to evaluate the effects induced by chronic microapplication of endothelin-1 on the anterior optic nerve microvasculature and to determine the dose-response characteristics of endothelin-1 on this vascular bed. Daily dosages between 4.69 x 10(-4) and 9.0 x 10(-1) micrograms/day of endothelin-1 were delivered continually over 3 days, and at a constant flow rate, to the perineural region of the anterior optic nerve of 15 albino rabbits via osmotically-driven minipumps. The vasomotor effect of local endothelin-1 on the microvasculature of the optic nerve was examined using intraluminal microvascular corrosion casting technique. The vasomotor effects were quantified by measuring the relative amount of vasoconstriction of the arterioles supplying the anterior optic nerve (primary and secondary branches of the short posterior ciliary arteries). The average constriction was calculated for the endothelin-treated eyes and the untreated, contralateral eyes. The mean vasoconstriction in the endothelin treated eyes ranged from 14.7% to 30.0% and was highly correlated with the logarithmic value of the daily dose of endothelin-1 (R2 = 0.59, p = 0.00083). The interocular difference (between treated and untreated eyes) of the optic nerve vasoconstriction ranged from 0-19% (mean +/- SD: 7.23 +/- 5.7%). This interocular difference also correlated highly with the log of the daily endothelin-1 dosage (R2 = 0.80; p < 0.0001). By additionally accounting for the weight and sex in a multiple linear regression function, the correlation was markedly improved (R2 = 0.92; p < 0.0001). In conclusion, the microvasculature supplying the anterior optic nerve of the rabbit demonstrates a dose-dependent vasoconstriction with chronic local application of endothelin-1. This in vivo, experimental model offers a titratable method with which the effects of chronic vasoconstriction and vascular insufficiency on the optic nerve can be examined.

Animals↗

PubMed1995

[Relationship between the nerve fiber layer defect and parafoveal visual field defects in glaucomatous eyes].

We evaluated the nerve fiber layer defect (NFLD) in glaucomatous eyes imaged by a scanning laser ophthalmoscope (SLO, Rodenstock Gm BH, Munich, Germany) and its relationship to parafoveal visual field defects. Twenty-three eyes of 20 patients with open angle glaucoma were studied. Only those eyes were used in which NFLD reaching the temporal raphe of the nerve fiber layer was observed by the SLO in either the superior or the inferior hemisphere. We defined three topographic parameters of the NFLD: 1. the angle (0, degree) generated by a line A passing through the foveal pit and the disc center, and a line through the disc center to the point of the NFLD at the disc edge and closest to line A, 2. the horizontal distance (D1, mm) along the temporal raphe between the foveal pit and the point of the NFLD nearest to the foveal pit, and 3. the vertical distance (D2, mm) between the foveal pit and the point of NFLD nearest to the foveal pit. We also defined the nearest defect location (in degrees from the fovea) as the stimulus point with sensitivity loss greater than 6 dB in the Humphrey visual field (program central 10-2). A highly significant correlation was observed between each of the three NFLD parameters and the nearest defect location (p < 0.001). The NFLD parameters we have newly defined here may be helpful for evaluating parafoveal visual functional damages in open angle glaucoma.

Female↗

PubMed1992

Determination of an appropriate laser setting for THC-YAG laser sclerostomy ab externo in rabbits.

To determine an appropriate setting for the THC-YAG laser (chromium-sensitized, thulium, and holmiumdoped YAG laser), we performed sclerostomy ab externo on 24 pigmented rabbits. The laser energy was delivered via a subconjunctivally-inserted fiberoptic probe that was placed at the limbus through a small conjunctival incision. We used four pulse-energy levels to perform the sclerostomies: 80 mJ, 120 mJ, 160 mJ, and 200 mJ. At all these levels, a new outflow pathway was easily created, a filtering bleb was formed, and intraocular pressure (IOP) was immediately reduced. Severe tissue damage around the sclerostomy site occurred with the 160-millijoule and 200-millijoule pulses. The 80-millijoule pulse created a relatively small patent sclerostomy, providing only relatively brief IOP reduction. We conclude that 120-millijoule is the most appropriate laser-pulse energy for use in pigmented rabbits.

Animals↗

PubMedDate not supplied

Holmium YAG laser sclerostomy ab externo for refractory glaucoma.

Ab externo thermal sclerostomy was performed with the holmium YAG (thulium, holmium, chromium-doped YAG crystal) laser in 21 eyes of 20 patients with refractory glaucoma. We used either the 5-fluorouracil (5-FU) or mitomycin C (MMC) antimetabolites in all cases. The rate of intraocular pressure (IOP) control defined as IOP < 21 mmHg regardless of whether antiglaucoma medication was applied postoperatively) was estimated by the life-table methods of Kaplan-Meier. The postoperative IOP control rate was 47.1% in the MMC-treated group at 57 months, and 14.3% in the 5-FU-treated group at 52 months. There were statistically significant differences in success rates between the MMC- and 5-FU-treated groups. We observed no clinically significant complications except excess filtration associated with a shallow anterior chamber in one case. This procedure is thought to have several advantages over more conventional filtration surgery; the operation time is shorter, and there is no need for intraocular manipulation, which means conjunctival trauma is minimal. However, the IOP control rate was substantially lower than that achieved via conventional trabeculectomy. Our results suggest that the selection of patients and the use of MMC is an important factor in maintaining successful filtration.

Adolescent↗

PubMedDate not supplied

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

PURPOSE: To evaluate the association between the watershed zone and glaucomatous optic nerve head (ONH) damage. METHODS: We performed indocyanine green fluorescence angiography with a scanning laser ophthalmoscope in 54 eyes of 27 patients with normal tension glaucoma (NTG). RESULTS: We identified 7 eyes of 8 patients (14.8%) with a watershed zone not including the ONH, 32 eyes of 20 patients (59.3%) with the watershed zone partially including the ONH, and 10 eyes of 14 NTG patients (25.9%) with the watershed zone including the ONH. Of the 27 NTG patients, 10 patients (37.0%) had different types in each eye. CONCLUSIONS: In these patients, the mean deviation of visual field indices was greater in the eye with the watershed zone, which included a larger part of the ONH than in the contralateral eye. Conversely, the eye with the greater mean deviation had a watershed zone that included a larger part of the ONH. The location of the watershed zone appeared to influence the progression of the visual field defect.

Adolescent↗