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Biomedical subjects

Atsuo Tomidokoro

Publications and source records attributed to Atsuo Tomidokoro.

At least 19 recordsLinked to original sources
PubMed2007

Frequency doubling technology perimetry in open-angle glaucoma eyes with hemifield visual field damage: comparison of high-tension and normal-tension groups.

PURPOSE: To evaluate the performance of frequency doubling technology (FDT) perimetry in open-angle glaucoma eyes with hemifield visual field damage and to compare it between open-angle glaucoma with high pressure [high-tension glaucoma (HTG)] and those with normal pressure [normal-tension glaucoma (NTG)] groups. METHODS: FDT perimetry with the N-30 full threshold protocol and standard automated perimetry (SAP) using the Humphrey Field Analyzer with the 30-2 full threshold protocol were performed in 20 eyes of 20 HTG patients and 36 eyes of 36 NTG patients with visual field damage confirmed with SAP in only one hemifield. RESULTS: There was no significant difference in demographics, the Heidelberg Retina Tomography indices, and the Humphrey Field Analyzer indices between HTG and NTG groups. Regarding the FDT perimetry results, mean deviation in the global field (P=0.009) and mean sensitivity in the SAP-spared (P=0.001) and SAP-impaired (P=0.011) hemifields were lower; the numbers of FDT abnormal test points (probability of abnormality <5%) in the SAP-spared hemifield were significantly greater (P=0.005) in HTG than in NTG groups. Eyes in which FDT results of the SAP-spared hemifield were judged as abnormal was more frequent in HTG groups (P=0.007). CONCLUSIONS: The performance of FDT perimetry to detect early or preperimetric glaucomatous functional changes should be different between HTG and NTG eyes.

Cross-Sectional Studies↗
PubMed2006

No apparent association between ocular perfusion pressure and visual field damage in normal-tension glaucoma patients.

PURPOSE: To investigate the correlation of ocular perfusion pressure (OPP) with general and localized visual field damage in normal-tension glaucoma (NTG) patients. METHODS: Correlations between OPP, blood pressure, age, intraocular pressure, refractive error, and extent of visual field damage in the eye with the worst mean deviation (MD) were investigated retrospectively in 94 eyes of 94 NTG patients. Visual fields were analyzed statistically with respect to 15 sectors between two age-matched groups of subjects with high or low OPP. RESULTS: Significant positive correlations were found between OPP and age (P < 0.001), blood pressure and age (P < 0.05), and MD and refractive error (P < 0.01). OPP had no significant correlation with MD or mean sensitivity in the visual field in any of the visual field sectors. CONCLUSION: OPP and systemic blood pressure have no evident effect on the extent or pattern of visual field damage in NTG.

Adolescent↗
PubMed2006

Performance of frequency-doubling technology perimetry in a population-based prevalence survey of glaucoma: the Tajimi study.

OBJECTIVE: To evaluate the performance of frequency-doubling technology (FDT) perimetry in a population-based glaucoma prevalence survey. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Participants older than 40 years randomly selected from the population of Tajimi City. METHODS: Each participant underwent screening ophthalmic examinations including a visual field test using FDT with the C-20-1 screening protocol. A diagnosis of glaucoma was determined by glaucoma specialists with another detailed visual field test using Humphrey Field Analyzer (HFA; Humphrey Instruments, San Leandro, CA) with the 30-2 Swedish interactive threshold algorithm standard protocol and stereoscopic disc photographs. MAIN OUTCOME MEASURES: The ratios of reliable FDT results and the sensitivity and specificity for detecting glaucoma in a general population. RESULTS: Of 5784 eyes of 2892 participants (age range, 40-92 years; refractive error, -23 to 11 diopters) in whom FDT was performed in both eyes, reliable results (< or =33% fixation loss and < or =33% false-positive errors) were obtained in 5707 eyes (98.7%), including 2871 right eyes (99.3%) and 2836 left eyes (98.1%) with a significant bilateral difference (P<0.001, chi-square test). The rate of reliable FDT results did not differ between men and women (P = 0.81) but decreased with age. In 5582 eyes with reliable FDT results, FDT showed 1 or more abnormal points in the visual field in 502 eyes (9.0%), including 388 (7.3%) of 5295 normal eyes, 19 (16.4%) of 116 eyes of glaucoma suspects, and 95 (55.6%) of 171 eyes with definite glaucoma. The sensitivity and specificity values for detecting definite glaucoma were 55.6% and 92.7%, respectively. The positive and negative predictive values were 18.9% and 98.5%, respectively. In further analyses stratified with the mean deviation (MD) of the HFA, the sensitivities were 32.1%, 48.4%, 73.7%, and 96.6% for detecting definite glaucoma with an MD of more than -2 dB, an MD of -2 dB or less and more than -5 dB, an MD of -5 dB or less and more than -8 dB, and an MD of -8 dB or less, respectively. CONCLUSIONS: In a population-based glaucoma screening study, FDT perimetry with the C-20-1 screening protocol was reliably performed in more than 98% of participants. The sensitivity for detecting glaucomatous visual field damages, especially early damage, was not sufficiently high, whereas the specificity was high.

Adult↗
PubMed2006

Optic disc topography and peripapillary retinal nerve fiber layer thickness in nonarteritic ischemic optic neuropathy and open-angle glaucoma.

OBJECTIVE: To evaluate the results of scanning laser tomography and scanning laser polarimetry (SLP) and the correlations with visual field damage (VFD) in eyes with nonarteritic ischemic optic neuropathy (n-AION) compared with eyes with open-angle glaucoma (OAG). DESIGN: Cross-sectional study. PARTICIPANTS: Thirty-three eyes of 33 patients with n-AION and 33 eyes with OAG whose age and VFD evaluated with the Humphrey field analyzer were matched to those of the n-AION eyes. MAIN OUTCOME MEASURES: The parameters of optic disc topography obtained with the Heidelberg Retina Tomograph II (HRT II) and retinal nerve fiber layer (RNFL) thickness with GDx with variable corneal compensation and the correlation to VFD. RESULTS: The cup area, cup-to-disc area ratio, and mean cup depth were significantly smaller, and the cup shape measure more negative, in the n-AION eyes than in the OAG eyes (P<0.001), whereas rim area was significantly greater (P<0.001). Multivariate analyses showed that none of disc area, rim area, and mean cup depth in the n-AION eyes and only rim area (P = 0.029) in the OAG eyes was significantly associated with mean deviation (MD). Ellipse average of RNFL thickness significantly correlated with MD in the n-AION eyes (P = 0.045) and in the OAG eyes (P = 0.022). CONCLUSIONS: Disc topography of eyes with n-AION was quantitatively characterized by small and shallow cupping and a relatively large rim area compared to eyes with OAG matched for age and VFD. In eyes with n-AION, significant correlation with VFD was found only for the RNFL thickness evaluated with SLP but not for the HRT II parameters.

Aged↗
PubMed2006

Correlation between hemifield visual field damage and corresponding parapapillary atrophy in normal-tension glaucoma.

PURPOSE: To evaluate the correlation between the superior or inferior half area of parapapillary atrophy (PPA) and the corresponding hemifield visual field damage (VFD) in normal-tension glaucoma. DESIGN: Cross-sectional study. METHODS: patients: One hundred nine eyes of 109 consecutive patients with normal-tension glaucoma. observation procedures: Topography parameters of the optic nerve head and PPA (zone beta) area were obtained with the Heidelberg Retina Tomograph (HRT), and VFD was evaluated with the 30 to 2 program of Humphrey Field Analyzer. The HRT parameters and PPA area were determined separately in superior and inferior half regions. main outcome measures: Partial correlation coefficients of the superior and inferior areas of PPA with refractive error, axial length, HRT parameters, and corresponding hemifield VFD. RESULTS: In simple correlation analyses, significant correlation was found between the inferior PPA area and the superior hemifield VFD (Spearman rank correlation coefficient; Rs = -0.32; P < .001) but not between the superior PPA area and the inferior hemifield VFD (Rs = 0.05; P = .6). Age, refractive error, axial length, and height variation contour were associated significantly with the total, superior, and inferior areas of PPA, respectively (P < .01). Multiple regression analyses showed that the superior PPA area was associated significantly with only axial length (P < .001), and the inferior PPA area was associated significantly with the axial length and the superior hemifield VFD (P < .001). CONCLUSIONS: In patients with normal-tension glaucoma, only the inferior half area of PPA correlated significantly with glaucomatous VFD. Axial length and myopia were associated with both the superior and inferior half areas of PPA.

Cross-Sectional Studies↗
PubMed2006

Prevalence and causes of low vision and blindness in a Japanese adult population: the Tajimi Study.

OBJECTIVE: To determine the prevalence and causes of low vision and blindness in a Japanese adult population. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Randomly selected residents (n = 3870) of Tajimi City, Japan, who were 40 years of age or older. METHODS: Of the 3021 study participants (78.1% of 3870 eligible persons), 2977 (76.9%) underwent a complete ophthalmologic examination including measurement of the best-corrected visual acuity (BCVA) with full subjective refraction using a Landolt ring chart at 5 m. Age- and gender-specific prevalence rates of low vision and blindness were estimated and causes were identified. MAIN OUTCOME MEASURES: Low vision and blindness were defined as BCVA in the better eye worse than 20/60 to a lower limit of 20/400 and worse than 20/400, respectively (World Health Organization [WHO] criteria) and worse than 20/40 but better than 20/200 and 20/200 or worse, respectively (United States criteria). RESULTS: The overall prevalence of blindness according to the WHO or U.S. criteria was 0.14% (n = 4; 95% confidence interval [CI], 0.06-0.32). The primary causes were optic atrophy, myopic macular degeneration, retinitis pigmentosa, and uveitis. The overall prevalence of low vision according to the WHO criteria was 0.39% (95% CI, 0.18%-0.60%) and according to the U.S. criteria was 0.98% (95% CI, 0.66%-1.30%), which was significantly greater in women and in the older half of the participants than in the younger half (P = 0.0079 and <0.0001, respectively). The leading causes of low vision in descending order were cataract followed by glaucoma, and those of monocular blindness were myopic macular degeneration, glaucoma, and trauma. CONCLUSIONS: The prevalence of low vision and blindness in Japanese adults was one of the lowest among those reported. The major causes of low vision were cataract and glaucoma, and the leading cause of monocular blindness was myopic macular degeneration.

Aged↗
PubMed2006

Plasma endothelin-1 level in Japanese normal tension glaucoma patients.

PURPOSE: To compare the plasma concentration of endothelin-1 (ET-1) among patients < 60 years of age with normal-tension glaucoma (NTG), primary open-angle glaucoma (POAG), and in age-matched normal participants. METHODS: Plasma concentration of ET-1 was determined in 30 NTG 18 POAG patients, and 19 age-matched normal participants using an enzyme immunoassay. RESULTS: The ET-1 level was 1.49 +/- 0.51 pg/ml in the NTG patients (49.4 +/- 8.8 years), 1.58 +/- 0.64 pg/ml in the POAG patients (44.7 +/- 10.7 years), and 1.33 +/- 0.50 pg/ml in the normal participants (49.9 +/- 5.6 years). The ET-1 levels were not significantly different among the three groups, and no significant correlation with the extent of visual field damage, intraocular pressure (IOP), refraction, or age was seen in the glaucoma patients. CONCLUSIONS: The plasma ET-1 level showed no difference among NTG patients, POAG patients, and normal participants < 60 years of age in the Japanese population.

Adult↗
PubMed2006

Long-term follow-up of initial trabeculectomy with mitomycin C for primary open-angle glaucoma in Japanese patients.

PURPOSE: To determine the long-term intraocular pressure (IOP) control and postoperative complications after initial trabeculectomy with use of mitomycin C (MMC) in patients with primary open-angle glaucoma (POAG). PATIENTS AND METHODS: A retrospective review was conducted of a consecutive series of 123 eyes (87 patients) with POAG who underwent initial trabeculectomy with MMC and had at least 4 years of follow-up. All patients underwent standard trabeculectomy with 0.04% MMC applied intraoperatively for 3 minutes. The long-term outcomes (IOP control and bleb leak, long-standing hypotony, bleb-related infections) were analyzed with the Kaplan-Meier life-table method on the basis of three definitions of successful IOP control (defined as IOP <18 mmHg (definition 1), IOP <16 mmHg (definition 2), and IOP decrease of by > or =30% and <21 mmHg (definition 3)). RESULTS: The mean follow-up time was 6.8+/-1.4 (mean+/-SD) years. The cumulative survival rates were 67.0+/-4.6%, 44.5+/-5.4%, and 74.1+/-4.2%, respectively, based on definitions 1, 2, and 3, 8 years postoperatively by life-table analysis. At 8 years, bleb leak occurred in 7.9+/-2.6% of eyes, long-standing hypotony in 8.3+/-2.5%, and bleb-related infections in 5.9+/-2.4%. CONCLUSION: Long-term outcome after initial trabeculectomy with MMC in Japanese POAG patients is comparable with that reported in other populations and with that after trabeculectomy with 5-fluorouracil.

Adult↗
PubMed2005

Psychometric properties of the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25), Japanese version.

BACKGROUND: The importance of evaluating the outcomes of health care from the standpoint of the patient is now widely recognized. The purpose of this study is to develop and test a Japanese version of the National Eye Institute Visual Function Questionnaire (NEI VFQ-25). METHODS: A Japanese version was developed with a previously standardized method. The questionnaire and optional items were completed by 245 patients with cataracts, glaucoma, or age-related macular degeneration, by 110 others before and after cataract surgery, and by a reference group (n = 31). We computed rates of missing data, measured reproducibility and internal consistency reliability, and tested for convergent and discriminant validity, concurrent validity, known-groups validity, factor structure, and responsiveness to change. RESULTS: Based on information from the participants, some items were changed to 2-step items (asking if an activity was done, and if it was done, then asking how difficult it was). The near-vision and distance-vision subscales each had 1 item that was endorsed by very few participants, so these items were replaced with items that were optional in the English version. For example, more than 60% of participants did not drive, so the driving question was excluded. Reliability and validity were adequate for all subscales except driving, ocular pain, color vision, and peripheral vision. With cataract surgery, most scores improved by at least 20 points. CONCLUSION: With minor modifications from the English version, the Japanese NEI VFQ-25 can give reliable, valid, responsive data on vision-related quality of life, for group-level comparisons or for tracking therapeutic outcomes.

Adult↗
PubMed2005

Penetration of topically applied fluorescein into eyes with avascular filtering bleb after trabeculectomy.

PURPOSE: To evaluate intraocular penetration of topical fluorescein in eyes with avascular blebs after trabeculectomy. DESIGN: Case control study. METHODS: The study included 11 eyes with open-angle glaucoma and functioning avascular blebs, six of which were treated with topical anti-glaucomatous medications and had no history of surgery, 15 with open-angle glaucoma, and untreated eyes suspected of having open-angle glaucoma. The fluorescein concentration in the superior peripheral and central corneal stroma and anterior chamber was determined 30 and 60 minutes after fluorescein instillation. RESULTS: The fluorescein concentration in the superior cornea was significantly higher in eyes with blebs or those topically treated than in untreated eyes (P <.01); there was no significant difference in the central cornea. The fluorescein concentration in the anterior chamber was much higher in eyes with blebs than in those that were untreated or topically treated (P <.001). CONCLUSION: The presence of avascular filtering blebs greatly enhances intraocular penetration of topically instilled fluorescein.

Administration, Topical↗
PubMed2005

Prevalence of appositional angle closure determined by ultrasonic biomicroscopy in eyes with shallow anterior chambers.

PURPOSE: To determine the prevalence of appositional angle closure in eyes with a shallow peripheral anterior chamber but no peripheral anterior synechia (PAS) in Japanese patients. DESIGN: Cross-sectional study. PARTICIPANTS: Eighty eyes of 80 consecutive patients with a shallow peripheral anterior chamber, determined using the method of van Herick, and no PAS. METHODS: The anterior chamber angle was classified according to Shaffer's grading with noncompression gonioscopy superiorly, inferiorly, temporally, and nasally. The absence of PAS was confirmed by compression gonioscopy if necessary. The presence of appositional angle closure and the trabecular-iris angle (T-I angle) was determined with ultrasound biomicroscopy in each quadrant under light and dark conditions. Factors related to appositional angle closure were studied using logistic analysis, and the covariates included gender, age, refraction, gonioscopic grading, and the quadrant of the angle measured. MAIN OUTCOME MEASURES: Gonioscopic grading of the angle width, the T-I angle, and the prevalence of appositional closure. RESULTS: The gonioscopic grading (P<0.001 in light and dark) and the T-I angle (P<0.001 in light and dark) varied significantly among the 4 quadrants. Narrower angle gradings were observed more frequently superiorly. The T-I angle was narrower superiorly (in light) and inferiorly (in dark) (P<0.001 and P = 0.040, respectively). The T-I angle was significantly narrower in dark than in light (P<0.001). The sites with the narrower gonioscopic gradings tended to have a smaller T-I angle (P<0.001 and P = 0.006 in light and dark, respectively). Appositional angle closure was found in at least 1 quadrant in 46 (57.5%) of 80 eyes in light and in 68 eyes (85%) in dark. Logistic analysis showed that gonioscopic grading and the quadrant were significantly related to the presence of appositional angle closure in light and dark (P<0.003 for both comparisons). CONCLUSIONS: Appositional angle closure was frequently observed in eyes with a shallow peripheral anterior chamber, especially under dark conditions in Japanese patients. The angle width, evaluated with conventional gonioscopic grading, and the quadrant of the angle were significantly related to the presence of appositional angle closure.

Aged↗
PubMed2005

Ocular distribution after topical instillation and potential neuroprotective effect after intravitreal injection of the calcium channel blocker iganipidine.

PURPOSE: To investigate the effects of iganidipine, a new calcium antagonist on glutamate agonist-induced retinal damage. METHODS: Iganidipine was injected with N-methyl-D-aspartate (NMDA) or kainic acid (KA) into the rat vitreous, and the retina was histologically examined. After co-injection with KA, the number of DiI-labeled retinal ganglion cells was also counted. Rabbits received unilateral instillation of 0.03% iganidipine twice daily for 14 days, and the iganidipine level in the posterior retina-choroid was determined by liquid chromatography/mass spectrometry. RESULTS: Coadministration of iganidipine had no significant effect on NMDA-induced thinning of the inner plexiform layer but partly suppressed KA-induced thinning at final intravitreous concentrations of 10(-8) M or higher, which was confirmed by counting the ganglion cell number. The iganidipine level in the posterior retina-choroid was approximately 6.2 x 10(-7) M in the instilled eye, which was higher than on the contralateral side by 5.2 x 10(-7) M (p = 0.035). CONCLUSIONS: Iganidipine suppressed KA-induced retinal damage in rats. This suppression was achieved with a lower concentration than that resulting from unilateral instillations of iganidipine in the ipsilateral posterior retina-choroid in rabbits.

Administration, Topical↗
PubMed2005

Time course of changes in optic nerve head circulation after acute reduction in intraocular pressure.

PURPOSE: To study the time course of changes in circulation in the optic nerve head (ONH) after acute reduction in intraocular pressure (IOP) and to evaluate the effects of a calcium antagonist, a nitric oxide synthetase (NOS) inhibitor, indomethacin, and sympathetic nerve amputation on the changes in ONH circulation after reduction of IOP. METHODS: In anesthetized albino rabbits, acute reduction of IOP (acute increase in ocular perfusion pressure [OPP]) was manometrically achieved and normalized blur (NB), a quantitative index of tissue blood velocity obtained with the laser speckle method, was serially monitored for 30 seconds and 60 minutes. The effects of systemic administration of 1 microg/kg per hour nilvadipine (a calcium antagonist), 300 microg/kg Nomega-nitro-l-arginine (l-NAME, a nonselective NOS inhibitor), and 5 mg/kg indomethacin or sympathetic nerve amputation on the changes in NB after reduction of IOP were studied. RESULTS: During changes in IOP from 10 to 40 mm Hg and then back to 10 mm Hg, NB exhibited no significant change. During changes in IOP from 10 to 60 mm Hg and then back to 10 mm Hg, NB initially decreased with an increase in IOP to 60 mm Hg and then increased to baseline level when IOP was returned to 10 mm Hg. In the nilvadipine-treated rabbits, during changes in IOP from 10 to 40 mm Hg and back to 10 mm Hg and during the changes from 10 to 60 mm Hg and back to 10 mm Hg, NB decreased with increase in IOP to 40 or 60 mm Hg and then increased to slightly above the baseline when IOP returned to 10 mm Hg. l-NAME, indomethacin, and sympathetic nerve amputation each had little effect on the time course of change in NB. CONCLUSIONS: ONH circulation was stably maintained after reduction of IOP from 40 to 10 mm Hg but not after that from 60 to 10 mm Hg. The changes in NB after reduction of IOP occurred quickly and were partially impaired with a calcium antagonist, but not with the NOS inhibitor, indomethacin, or sympathetic nerve amputation. These findings suggest the importance of vascular smooth muscle in maintaining stable ONH circulation against reduction of IOP in a fashion nearly independent of NO, endogenous prostaglandins, and the sympathetic nervous system.

Acute Disease↗
PubMed2004

Corneal regular and irregular astigmatism assessed by Fourier analysis of videokeratography data in normal and pathologic eyes.

PURPOSE: To assess corneal regular and irregular astigmatism using Fourier series harmonic analysis of videokeratography data in normal subjects, as well as in subjects with pathologic and postsurgical conditions. STUDY DESIGN: Retrospective, case-control study. PARTICIPANTS: Two hundred normal eyes, 58 eyes with keratoconus, 24 eyes with suspect keratoconus, 100 eyes that underwent LASIK, 101 eyes that underwent photorefractive keratectomy (PRK), and 79 eyes that underwent penetrating keratoplasty (PK). METHODS: Videokeratography data were decomposed, using Fourier analysis, into spherical power, regular astigmatism, asymmetry, and higher order irregularity. RESULTS: The normal range of the Fourier indices was defined as the mean +/-2xstandard deviation in the normal eyes, which were 40.81-47.13 diopters (D) for spherical power, 0-1.04 D for regular astigmatism, 0.02-0.68 D for asymmetry, and 0.05-0.17 for higher order irregularity. The keratoconus and suspect keratoconus groups showed significantly greater values in all indices than did the normal group (P<0.001 or 0.0001, Mann-Whitney test with Bonferroni correction). Eyes that had undergone LASIK and PRK had significantly smaller spherical power and regular astigmatism (P<0.0001) and significantly larger asymmetry (P<0.0001) than the normal eyes. All indices were significantly greater in the PK group than in the normal group (P<0.0001). Among the eyes tested in this study, eyes with keratoconus had the largest asymmetry, whereas eyes that had undergone PK had the most irregular corneas. CONCLUSIONS: The normal range was defined for the corneal irregular astigmatism index (asymmetry and higher order irregularity) to support future studies in this field. Eyes with ocular pathologic and postsurgical conditions were evaluated using the normal range.

Adolescent↗
PubMed2004

Influence of peripheral iridectomy on intravitreous penetration of topical nipradilol.

PURPOSE: Penetration of drug from the anterior chamber to the vitreous is substantial in aphakic eyes, but negligible in normal phakic eyes. The purpose of this study is to investigate the effect of the presence of peripheral iridectomy (PI) which bypasses iris-lens diaphragm on the drug penetration from the anterior chamber to the vitreous. METHODS: Twelve Japanese White rabbits underwent PI in a randomly chosen eye and the same procedures except removal of the peripheral iris in the contralateral eye. Nine weeks after the procedure, topical instillation of 20 microl of 1% nipradilol into the both eyes was repeated three times at five-minute intervals, and two hours later the animals were sacrificed and the both eyes were enucleated. Concentrations of nipradilol in the aqueous and vitreous were determined using a high-performance liquid chromatography. RESULTS: The concentrations of nipradilol were significantly greater in the eyes with PI than those in the contralateral control eyes in the aqueous (5636 +/- 1688 vs 2835 +/- 663 ng/g, mean +/- standard error, n = 12, p = 0.0028) and in the anterior vitreous (11.9 +/- 2.5 vs 5.6 +/- 1.0 ng/g, p = 0.0047), while not in the posterior vitreous or in the posterior retina-choroid. The ratios of the nipradilol concentrations in the anterior or posterior vitreous to that in the aqueous were not significantly different between the both eyes. CONCLUSIONS: The presence of PI had little effect on the penetration of topically instilled nipradilol from the anterior chamber to vitreous.

Administration, Topical↗
PubMed2004

Quantitative assessment of videokeratography data using fourier series harmonic analysis.

PURPOSE: To describe a method of mathematically decomposing videokeratography data using Fourier series harmonic analysis and present examples of its clinical application. METHODS: Videokeratography data were decomposed by Fourier analysis into spherical component, regular astigmatism, asymmetry (decentration or skewness), and higher-order irregular astigmatism. These 4 Fourier components were analyzed in both normal and pathologic eyes. Color-coded maps were generated to present the 4 Fourier components. RESULTS: Color-coded mapping of the results of Fourier analysis of videokeratography data facilitated visual and instant interpretation of complex corneal topographic information. By using Fourier components, time course of changes in corneal topography following penetrating keratoplasty and influence of suture removal were quantitatively evaluated. The Fourier analysis method was successfully applied to determine the most appropriate correction lenses in eyes after penetrating keratoplasty. CONCLUSIONS: Fourier analysis of videokeratography data allows mathematical separation of regular and irregular astigmatism and is useful in the quantitative assessment of corneal optics in eyes with both pathologic and postsurgical conditions.

Adult↗
PubMed2003

Time course of the change in optic nerve head circulation after an acute increase in intraocular pressure.

PURPOSE: To investigate the time course of changes in optic nerve head (ONH) circulation after an acute increase in intraocular pressure (IOP), by using the laser speckle method, and to evaluate the effects of a calcium antagonist, the nitric oxide synthetase inhibitor, indomethacin, or sympathetic nerve amputation on the response in ONH circulation after an acute increase in IOP. METHODS: In rabbits, the normalized blur (NB) level, a quantitative index of tissue blood velocity in the ONH, was monitored for 60 minutes after an increase in IOP from 20 mm Hg to 40, 50, or 60 mm Hg and for 25 seconds after increase in IOP from 20 mm Hg to 50 or 60 mm Hg with high time resolution. The effects of systemic administration of 1 micro g/kg per hour nilvadipine (a calcium antagonist), 30 mg/kg N(omega)-nitro-L-arginine (L-NAME), or 5 mg/kg indomethacin, or those of sympathetic nerve amputation on the time course of the changes in NB were studied. RESULTS: NB showed a quick recovery within several seconds after increase in IOP to 40 or 50 mm Hg, whereas no or little recovery occurred after an increase to 60 mm Hg. The nilvadipine treatment significantly increased NB at IOP of 20 mm Hg (baseline NB, P = 0.045) and apparently impaired the recovery of NB after the increase in IOP. After L-NAME administration, baseline NB significantly decreased (P = 0.028), and the NB recovery time was slightly but significantly prolonged (P = 0.012). Indomethacin showed no effects on baseline NB or NB recovery. Sympathetic nerve amputation increased baseline NB (P = 0.027), but did not influence NB recovery. CONCLUSIONS: The current results showed a quick recovery response in the ONH circulation after an acute increase in IOP in rabbits. A calcium antagonist impaired the response. Production of nitric oxide or prostaglandins or the sympathetic nervous system is probably not mainly responsible for the reaction.

Animals↗