Relationship between the Vertical Asymmetry of the Posterior Pole of the Eye and the Visual Field Damage in Glaucomatous Eyes.

PURPOSE: This study investigated the relationship between the shape of the posterior pole of the eye and the vertical asymmetry of visual field (VF) damage in glaucomatous eyes. DESIGN: Cross-sectional study. PARTICIPANTS: A total of 83 eyes of 43 patients with open-angle glaucoma. METHODS: The VF was measured using the Humphrey 24-2 or 30-2 Swedish Interactive Thresholding Algorithm (SITA) standard. The vertical asymmetry of VF damage was defined as the difference between the mean total deviation (mTD) values of the superior and inferior hemi-retinas. This difference was calculated for the hemifield, central, middle, and peripheral areas. A vertical cross-sectional image of the macula was obtained, and the magnitudes of superior and inferior retinal tilt (RT) were calculated as the difference between the lower margins of the retinal pigment epithelium (RPE) at the fovea and at a location 2 mm superior or inferior to the RPE. The RT asymmetry was defined as the difference between the inferior and superior RT. Data were analyzed using a multivariate linear mixed model. MAIN OUTCOME MEASURES: The relationship between mTD asymmetry (hemifield, central, middle, and peripheral) and both RT asymmetry and other factors (intraocular pressure, axial length, corneal radius, age, gender, mean deviation, refraction, and visual acuity) was assessed. RESULTS: The inferior RT was significantly larger than the superior RT (P < 0.001). Hemifield mTD asymmetry was related to RT asymmetry (P = 0.017). These relationships were significant in the middle (P = 0.029) and peripheral areas (P = 0.023), but not in the central area (P = 0.40). Other factors were not related to mTD asymmetry. CONCLUSIONS: Vertical asymmetry of the posterior pole was related to the vertical asymmetry of glaucomatous VF damage.

Location of Ocular Tessellations in Japanese: Population-Based Kumejima Study.

Purpose: Tessellation of the ocular fundus is commonly found at a mild stage in myopic eyes, and their locations vary among individuals. We conducted this study to determine the distribution of tessellation locations in a population study. Methods: A cross-sectional, population-based study. Residents of Kumejima older than 40 years were studied. The subjects filled out a comprehensive questionnaire, had their body height (BH) measured, and had an ocular examination. The location of the tessellation was classified into 6 patterns. Correlations between each pattern and the axial length (AL), age, and BH were statistically determined. Results: Reliable measurements of the AL and fundus photographs of the right eyes were obtained from 1670 subjects. Nine hundred eleven eyes had no tessellation, 113 eyes had tessellation in the posterior pole, 118 eyes had tessellation in the macular area, 383 eyes had tessellation in the peripapillary region, 6 eyes had tessellation in the nasal region, and 239 eyes had tessellation in the inferior region. The AL of the "no tessellation" group was significantly shorter than that of the posterior pole and macular groups (P < 0.01). The individuals of the posterior pole and peripapillary groups were significantly older than in all other groups (P < 0.05) except for the nasal group. The individuals in the inferior tessellation group were significantly taller than those in the no tessellation, posterior pole, and peripapillary groups (P < 0.01). Conclusions: The location distribution of the tessellation is important in correctly interpreting and predicting myopic changes.

Relationship between retinal artery trajectory and axial length in Japanese school students.

PURPOSE: The trajectories of the supratemporal and infratemporal retinal arteries are associated with the position of the nerve fiber layer defects of glaucomatous eyes. However, no reports have thus far been published on changes in the retinal artery trajectory (RA trajectory) along with growth. Thus, the purpose of this study was to investigate the differences in the RA trajectories of elementary and junior high school students and the associations with axial length (AL). STUDY DESIGN: Prospective cross-sectional observational study. METHODS: In total, 122 right eyes of healthy elementary school students (61 boys, 61 girls) and 170 right eyes of healthy junior high school students (83 boys, 87 girls) were studied. The AL was measured and color fundus photographs were taken, and used for the analysis. The RA trajectory was plotted in the color fundus photographs and fitted to a second-degree polynomial equation, [Formula: see text], using ImageJ. The coefficient "a" represented the steepness of the trajectories. The differences in the RA trajectories and ALs of elementary and junior high school students were determined using the Mann-Whitney test. The association between the RA trajectory and AL was determined using the Spearman rank correlation. RESULTS: The AL and the RA trajectory of the junior high school students were significantly greater than those of the elementary school students (P < 0.001). The RA trajectory was significantly associated with the AL in both elementary (r = 0.26, P = 0.005) and junior high (r = 0.32, P < 0.001) school students. CONCLUSIONS: Junior high school students have a longer AL and narrower RA trajectory than do elementary school students. A longer AL is associated with a narrower RA trajectory in both elementary and junior high school students.

Correlations between local peripapillary choroidal thickness and axial length, optic disc tilt, and papillo-macular position in young healthy eyes.

Optical coherence tomography (OCT) has made it possible for clinicians to measure the peripapillary choroidal thickness (ppCT) noninvasively in various ocular diseases. However, the ocular factors associated with the ppCT have not been conclusively determined. The purpose of this study was to determine the relationship between the local ppCT and the axial length, optic disc tilt, and the angle of the papillo-macular position (PMP) in healthy eyes. This was a prospective, observational cross-sectional study of 119 right eyes of 119 healthy Japanese volunteers. The ppCT was manually measured at eight sectors around the optic disc using the B-scan images of the Topcon 3D OCT RNFL 3.4 mm circle scan. The trajectory of the retinal pigment epithelium in the B-scan image was fitted to a sine curve using ImageJ, and the amplitude of the sine curve was used to determine the degree of the optic disc tilt. The PMP angle was determined in the color fundus photographs. The relationships between the ppCT and the axial length, the optic disc tilt, and PMP angle were determined by Spearman and multiple correlation analyses. The mean age was 25.8 ± 3.9 years and the mean axial length was 25.5 ± 1.4 mm. The ppCT was significantly and negatively associated with the axial length (R = -0.43 to -0.24, P<0.01) and positively associated with the PMP angle (R = 0.28 to 0.37, P<0.01) in all eight circumpapillary sectors. The temporal and infratemporal ppCTs were significantly and negatively associated with the optic disc tilt (R = -0.31, -0.20, P<0.05). The results of multiple regression analyses were similar to that of Spearman correlation analysis. In conclusion, the axial length and PMP angle can affect the ppCT in all circumferential sectors, however the tilt of the optic disc is correlated with only some of the sectors. This should be remembered in interpreting the ppCT.

Association of lifestyle and body structure to ocular axial length in Japanese elementary school children.

BACKGROUND: The purpose of this study is to determine whether the lifestyle and body stature are significantly associated with the axial length (AL) of the eyes of Japanese third grade students. METHODS: A prospective, cross sectional, observational study was performed on 122 third grade students consisting of 61 boys and 61 girls ages 8 to 9 years. The AL, body height, body weight, and body mass index (BMI) were measured. The lifestyle was determined by activities such as the daily duration of indoor studying, television viewing, use of computers and smart phones, outdoor activity time, bed time, Japanese or Western dietary habits, and parental myopia were investigated by a questionnaire with three or five grade levels. The relationship between AL and the questionnaire variables were analyzed by Spearman's correlation analyses. RESULTS: Westernized dietary habits (r = -0.24, P = 0.01), duration of computer and smart phone use (r = 0.24, P = 0.008), parental myopia (r = 0.39, P < 0.001), body weight (r = 0.26, P = 0.005), and BMI (r = 0.23, P = 0.011) were significantly correlated with the AL. Multiple logistic regression analyses showed that the sex [r = -0.48; 95% confidence interval (CI) -0.80 to -0.17, P = 0.003], body weight (r = 0.04; 95% CI 0.02 to 0.07, P = 0.038), westernized dietary habits (r = -0.30; 95% CI -0.55 to -0.05, P = 0.021), and parental myopia (r = 0.40; 95% CI 0.20 to 0.61, P < 0.001) were significantly and independently correlated with the AL. CONCLUSIONS: The body weight and parental myopia and westernized dietary habits are factors significantly associated with myopia. Changing from Japanese food style to westernized food style might increase the risk of progression of school myopia.

Structural parameters associated with location of peaks of peripapillary retinal nerve fiber layer thickness in young healthy eyes.

The location of the peaks of the circumpapillary retinal nerve fiber layer (cpRNFL) thickness is affected by several ocular parameters. In this study, we have generated equations that can determine the peaks of the cpRNFL. This study was a prospective, observational, cross sectional study of 118 healthy right eyes. The axial length, optic disc tilt, superiortemporal (ST)- and inferiortemporal (IT)-peaks of the cpRNFL thickness, and angles of the ST and IT retinal arteries (RA) and veins (RV) were determined. The correlations between the location of the ST- and IT-peaks and ocular structural parameters and the sex, body height and weight were calculated. The best fit equations to generate the location of the ST/IT-peaks were determined using corrected-Akaike Information Criteria. The location of the ST-peak was 0.72+(0.40 x ST-RA)+(0.27 x ST-RV)+(0.14 x height)-(0.47 x papillo-macular-position)-(0.11 x disc tilt) with a coefficient of correlation of 0.61 (P<0.0001). The location of the IT-peak was 21.88+(0.53 x IT-RA)+(0.15 x IT-RV)+(0.041 x corneal thickness)-(1.00 x axial length) with a coefficient of correlation of 0.59 (P<0.0001). The location of ST/IT peaks is determined by different parameters of the ocular structure. These equations allow clinicians to obtain an accurate location of the peaks for a more accurate diagnosis of glaucoma.

Correlations Between Retinal Nerve Fiber Layer Thickness and Axial Length, Peripapillary Retinal Tilt, Optic Disc Size, and Retinal Artery Position in Healthy Eyes.

PURPOSE: To determine the correlations between the retinal nerve fiber layer thickness (RNFLT) and the axial length, peripapillary retinal tilt (PRT), and optic disc size, and retinal artery position. METHODS: A prospective, observational cross-sectional study of 119 healthy right eyes of 119 volunteers. All participants underwent comprehensive ophthalmologic examinations including peripapillary RNFLT imaging and measurements of the axial length. The RNFLT was determined by the TOPCON 3D OCT-1000, MARK II. The RNFLT in a 3.4 mm circular scan was divided into 12 clock-hour sectors and 4 quadrant sectors around the optic disc. The PRT was assessed using the RNFLT B-scan images. The angle between the supra-temporal and infra-temporal retinal arteries was determined in the color fundus photographs. The correlations between the sectorial RNFLTs and the axial length, PRT, optic disc size, and artery angles were determined by simple and multiple regression analyses. RESULTS: Multiple regression analyses showed that the nasal and inferior quadrants and the whole RNFLT were significantly and negatively correlated with the axial length (standardized coefficient (SC)=-0.39 to -0.30, P<0.05). The PRT was significantly and positively associated with all of the quadrants and the whole RNFLT (SC=0.22 to 0.45, P<0.05). The retinal artery angle was significantly and negatively associated with the temporal RNFLT and positively associated with inferior RNFLT (SC=-0.49 to 0.31, P<0.05). The optic disc size was significantly and positively associated with the superior and nasal quadrants, and the whole RNFLT (SC=0.20 to 0.27, P<0.05). CONCLUSIONS: The axial length, PRT, optic disc size, retinal artery angle can affect the peripapillary RNFLT. These variables should be considered when assessing the peripapillary RNFLT.

Peripapillary Nerve Fiber Elevation in Young Healthy Eyes.

PURPOSE: Eyes with a peripapillary nerve fiber elevation (pNFE) are those with a discrepancy between the optic disc margin in a color fundus photograph and the Bruch's membrane opening in an optical coherent tomographic (OCT) cross-sectional image. The purpose of this study was to determine the prevalence of pNFE in young healthy eyes, and to compare the axial length and optic disc tilt between pNFE and non-pNFE groups. METHODS: This was a prospective, observational, cross-sectional study of 117 right eyes. All participants (mean age 25.8 ± 4.0 years) underwent a comprehensive ophthalmologic examination. The pNFE was determined from the color fundus photographs, scanning laser ophthalmoscopic images, and optic disc cross-sectional OCT images. The degree of optic disc tilt was determined by the sine curve technique. Mann-Whitney U tests were used to determine the significance of the differences in the axial length and optic disc tilt between the pNFE and non-pNFE groups. RESULTS: Fifty-nine eyes were placed in the pNFE group and 58 eyes in the non-pNFE group. The axial length of the pNFE group (26.0 ± 1.4 mm) was significantly longer than that of the non-pNFE group (24.9 ± 1.2 mm; P < 0.001). The optic disc tilt of the pNFE group (42.1 ± 16.5 pixels) was significantly greater than that of the non-pNFE group (33.2 ± 16.8 pixels; P = 0.003). CONCLUSIONS: The presence of pNFE is not rare in young healthy eyes. The eyes with pNFE have longer axial lengths and greater optic disc tilt. The pNFE should be considered when the disc margin is assessed.

Location of Tessellations in Ocular Fundus and Their Associations with Optic Disc Tilt, Optic Disc Area, and Axial Length in Young Healthy Eyes.

Tessellated fundus is found as common and early-phase characteristic of myopic eyes and their locations are varied among patients. However, the relationship between their locations and morphological parameters of the eyes is still unknown. The purpose is this study is to determine the locations of the tessellations in the ocular fundus of young healthy eyes, and to determine relationships between their locations and morphological parameters of the eyes. This is a prospective observational cross sectional study of 126 eyes of 126 healthy volunteers (mean age 26.0±4.1 years). The eyes were classified into eight groups based on the location of the tessellations; no tessellation, temporal, infra-temporal, inferior, nasal, peripapillary, whole retina, and unclassified tessellations. The degree of optic disc tilt was quantified using a sine curve fitting program on the optical coherence tomographic circle scan images. The correlations between each tessellation location and the axial length, area of the optic disc plus conus (AOC), and optic disc tilt were determined. Forty-four eyes were place in the no tessellation group, 12 eyes in the temporal, 21 eyes in the infra-temporal, 9 eyes in the inferior, 8 eyes in the nasal, 15 eyes in the peripapillary, 11 eyes in the whole, and 6 eyes in the unclassified groups. The differences in the axial lengths between the no tessellation group and the infra-temporal groups were significant. A significant difference was found in the AOC between the no tessellation and the inferior, infra-temporal, and peripapilalry groups. A significant difference was found in the optic disc tilt between the no tessellation and infra-temporal groups (P<0.05). The tessellations are located at specific sites in the fundus of young healthy eyes with the infra-temporal location most frequent. It was correlated with some parameters associated with myopia.

Association of retinal thickness and optic disc-to-fovea angle to axial length of young healthy eyes.

AIM: To determine the relationship between the axial length (AL) and the retinal thickness in the posterior pole and to the optic disc-to-fovea (ODF) angle of healthy eyes. PROCEDURES: A prospective, observational cross-sectional study (registration number, UMIN000006040) of 64 healthy right eyes (mean age 26.0±4.5 years) was performed. The thickness of the 64 areas within the central 24° area were measured in the Spectralis spectral domain-optical coherent tomographic images obtained by posterior pole scans. Each area was 3°×3°. The ODF angle was measured in each fundus photograph. The relationships between the AL and the retinal thickness of each of the 64 areas and the ODF angle were investigated by linear regression analyses. RESULTS: The mean AL was 25.0±1.3 mm and the mean ODF angle was 17.2°±1.0°. The average retinal thickness of the four areas around the fovea was constant and not significantly correlated with the AL. However, the retinal thicknesses of 54 of the other 60 areas were significantly and negatively correlated with the AL (R=-0.25 to -0.56, P<0.05). The ODF angle was also constant and not significantly correlated with the AL (R=-0.17, P=0.19). CONCLUSION: The lack of significant correlations between the AL and the retinal thicknesses of the central 6° or the ODF angle suggests that there might be some feedback system to keep the central retinal thickness and ODF angle constant regardless of an elongation of the AL.

Circumpapillary course of retinal pigment epithelium can be fit to sine wave and amplitude of sine wave is significantly correlated with ovality ratio of optic disc.

The purpose of this study was to develop a method of quantifying the degree of optic disc tilt in normal eyes. This was a prospective, observational cross sectional study of 126 right eyes of 126 healthy volunteers. The optic disc tilt was determined from the circular peripapillary optical coherence tomographic (OCT) scan images. The course of the retinal pigment epithelium (RPE) layer in the peripapillary cross sectional scan images was fit to a sine wave curve, and the amplitude of the sine curve was used to reflect the degree of the optic disc tilt in the optical axis. The repeatability of the amplitude determinations was calculated. The correlation between the amplitude and the ovality ratio of the optic disc was determined. The correlation between the amplitude and the body height was also calculated. The mean amplitude was 36.6 ± 17.5 pixels, which was significantly and inversely correlated with the ovality ratio of the optic disc (R = -0.59, P < 0.001). The intra-rater and inter-rater correlation coefficients of the amplitude were significant high (P < 0.001, both). The amplitude was significantly and inversely correlated with the body height (R = -0.38, P < 0.001), but not with the axial length. In conclusion, a sine wave function can be used to describe the course of the RPE in the circumpapillary OCT images. The results indicate that the amplitude of the sine wave can be used to represent the degree of optic disc tilt. Thus, the sine wave analyses can be used as a quantifiable and repeatable method to determine the optic disc tilt.

Posterior pole asymmetry analyses of retinal thickness of upper and lower sectors and their association with peak retinal nerve fiber layer thickness in healthy young eyes.

PURPOSE: To determine the symmetry of the retinal thicknesses (RT) between the 32 pairs of superior and inferior sectors by posterior pole asymmetrical analysis (PPAA) of the spectral-domain optical coherence tomographic (SD-OCT) images in healthy eyes. In addition, to determine their association with the position of the peak retinal nerve fiber layer (RNFL) thickness. METHODS: A prospective, observational, cross-sectional study of 64 right eyes. The Spectralis SD-OCT was used to obtain the images, and the PPAA determined the RT of the 64 cells within the central 24° area. The program also compared the thicknesses of corresponding cells across the fovea-disc axis. Circular scans were used to measure the supra- and infratemporal RNFL peak angle differences (PADs). The relationships between the RT of the corresponding cells and the relationship between the differences of the RT of the corresponding cells and PAD were investigated by linear regression analysis. RESULTS: The mean differences between the RT of corresponding cells ranged from 3.1 to 23.2 µm. The RT of all upper cells were significantly correlated with the RT of the corresponding lower cells (R = 0.45-0.97, P < 0.001). The coefficients of correlation between the corresponding pairs of central- and temporal-macular cells were higher than that of the peripheral and nasal-macular cells. The differences of the pairs of nasal-macular cells RT were significantly correlated with the PAD. CONCLUSIONS: The symmetry of the RT between the upper and lower cells was high in the central and temporal-macular areas but not in the peripheral and nasal-macular areas. (www.umin.ac.jp/ctr number, UMIN000006040.).

Quantification of retinal nerve fiber and retinal artery trajectories using second-order polynomial equation and its association with axial length.

PURPOSE: To determine whether a second-degree polynomial equation can fit the retinal nerve fiber (RNF) and retinal artery (RA) trajectories in the posterior pole of eyes and whether the RNF and RA trajectories are correlated with the axial length of the eye. METHODS: This was a prospective observational cross-sectional study of 109 right eyes of 109 healthy participants. All participants underwent axial length measurements, optical coherence tomography (OCT) to determine the peripapillary retinal nerve fiber layer (RNFL) thickness, and red-free fundus photography. The supratemporal and infratemporal peaks of the RNFL thickness were determined in the OCT RNFL circle scan images. The trajectories of the RNF passing through the peaks of the RNFL thickness were plotted in the red-free fundus photographs and were fitted to a second-degree polynomial equation (ax(2)/100 + bx + c) by ImageJ. The coefficient a represented the steepness of the trajectories. Intraclass correlation coefficient was used to measure the reliability between the raters. The relationships between the RNF or RA trajectories and the axial length were investigated using linear regression analyses. RESULTS: The mean axial length was 25.5 ± 1.4 mm, and the mean RNF trajectory and the mean RA trajectory, a, were 0.472 ± 0.123 and 0.442 ± 0.109, respectively. The intrarater and interrater correlation coefficients of the RNF trajectories were 0.954 and 0.881, respectively. The RNF and RA trajectories were significantly and positively correlated with the axial length (R = 0.28, 0.33, P < 0.01). CONCLUSIONS: A longer axial length is associated with narrower RNF and RA trajectories. (www.umin.ac.jp/ctr number, UMIN000006040.).

Relationship between supernormal sectors of retinal nerve fibre layer and axial length in normal eyes.

PURPOSE: To determine the effect of the axial length on the supernormal and false-positive sectors of the peripapillary retinal nerve fibre layer (RNFL) in healthy eyes using the normative database embedded in a spectral domain optical coherence tomographic (SD-OCT) instrument. METHODS: This was a prospective, observational cross -sectional study. The right eyes of 126 healthy young volunteers were studied. The RNFL thickness was measured by SD-OCT in twelve 30-degree sectors (clock hours) around the optic disc. The sectors whose RNFL thickness was <5% probability level were labelled as false-positive sectors. The sectors >95% probability level were labelled as supernormal sectors. The relationships between the axial length and rates of supernormal and false-positive sectors were investigated. RESULTS: A longer axial length was significantly associated with an increase in the rates of supernormal thickness in sector 8 (odds ratio, [OR], 1.494; p = 0.010) and sector 10 (OR, 1.529; p = 0.008). The supernormal sectors were mainly located in the temporal region. A longer axial length was significantly associated with a higher rates of false positives in sector 5 (OR, 1.789; p = 0.017), sector 6 (OR, 2.305; p < 0.001) and sector 12 (OR, 2.277; p = 0.035). CONCLUSIONS: The axial length was significantly related to the rates of supernormal and false-positive sectors even in healthy eyes. These findings indicate that the specificity and sensitivity of SD-OCT will be affected especially in eyes with longer axial lengths.

Association between retinal thickness of 64 sectors in posterior pole determined by optical coherence tomography and axial length and body height.

PURPOSE: We determined a significant correlation between the retinal thickness (RT) in 64 cells or sectors of the posterior pole, and the axial length (AL) and the body height (BH). METHODS: A prospective, observational cross-sectional study of 64 right eyes of 64 healthy volunteers (mean age, 26.0 ± 4.5 years; range, 22-39 years). The RT within the central 24° area was measured in the Spectralis spectral domain-optical coherence tomographic (SD-OCT) images. The correlations between the RT and the AL or the BH were determined by linear regression analyses. RESULTS: The mean ± SD of the AL was 25.04 ± 1.30 mm, and that of the BH was 167.2 ± 8.5 cm. The RTs of the central four cells around the fovea were not significantly correlated with the AL. The RTs of 54 cells were significantly and negatively associated with the AL (r = -0.25 to -0.56, P < 0.05). In contrast, the RTs of the central to temporal eight cells were significantly and positively correlated with the BH (r = 0.26-0.37, P < 0.05). The RTs of 56 cells were not significantly correlated with the BH. CONCLUSIONS: The RT of the posterior retina, except in the fovea, decreased as AL elongated, and those of the central temporal areas were significantly correlated with the BH. Thus, the AL and BH must be considered when the RT is evaluated. The 64-sector analysis on OCT is useful to assess the detailed changes of RT affected by them. (http://www.umin.ac.jp/ctr/index.htm number, UMIN000007154.).

Relationship between position of peak retinal nerve fiber layer thickness and retinal arteries on sectoral retinal nerve fiber layer thickness.

PURPOSE: We determined the relationship between the position of the peak of the retinal nerve fiber layer (RNFL) thickness, and the retinal arteries, axial length (AL), and sectoral RNFL thickness in healthy eyes. METHODS: A prospective, observational cross-sectional study (registration number, UMIN000006040) of 50 healthy right eyes (mean age 25.8 ± 3.7 years) was performed. The RNFL thickness was measured by optical coherence tomography in twelve 30° sectors (clock hours) around the optic disc. The RNFL nasal-superior-temporal-inferior-nasal curves and fundus photographs were used to measure the angles between the supratemporal and infratemporal peak RNFL positions (peak angle), and the retinal artery angle (artery angle), respectively. The relationships between the peak angle, artery angle, AL, and sectoral RNFL thickness were investigated by linear regression analyses. RESULTS: The peak angles were highly correlated with the artery angle (r = 0.92, P < 0.001) and correlated negatively with the AL (r = -0.49, -0.38; P < 0.01). After excluding the effect of the AL, the peak and artery angles were correlated significantly with the sectoral RNFL thickness in 8 sectors. After excluding the effect of the peak angle, the AL was correlated significantly with the sectoral RNFL thicknesses in only one sector. CONCLUSIONS: The temporal RNFL thickness increased as the superior and inferior RNFL peaks, and retinal arteries shifted toward the fovea, whereas an inverse relationship was observed for the inferior and supranasal areas. The sectoral RNFL thickness is correlated better with the peak and artery angles than the axial length. (https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary &recptno=R000007154&language=J number, UMIN000006040.).