Hideki Nomura

Refractive errors and factors associated with myopia in an adult Japanese population.

PURPOSE To investigate the refractive status and factors associated with myopia by a population-based survey of Japanese adults. METHODS A total of 2168 subjects aged 40 to 79 years, randomly selected from a local community, were assessed in a cross-sectional study. The spherical equivalent of the refractive error was calculated and used in a multiple logistic regression analysis to evaluate the relationships between myopia and possible related factors. RESULTS The mean (+/- SD) of the spherical equivalent was -0.70 +/- 1.40 diopters (D) in men, and -0.50 +/- 1.44 D in women. Based on +/- 0.5 D cutoff points, the prevalence of myopia, emmetropia, and hypermetropia were 45.7%, 40.8%, and 13.5% in men, and 38.3%, 43.1%, and 18.6% in women, respectively. A 10-year increase in age was associated with reduced risk of myopia [men: odds ratio (OR) = 0.53, 95% confidence interval (CI): 0.44-0.62; women: OR = 0.65, 95% CI: 0.54-0.78]. In men, myopia was significantly associated with higher education (high school: OR = 1.6, 95% CI: 1.1-2.3; college: OR = 2.0, 95% CI: 1.3-3.1) and management occupations (OR = 1.6, 95% CI: 1.0-2.4). For women, high income (OR = 1.5, 95% CI: 1.1-2.2), and clerical (OR = 1.5, 95% CI: 1.0-2.4) and sales/service occupations (OR = 1.7, 95% CI: 1.1-2.6) were also associated with myopia. CONCLUSIONS The prevalence of myopia in a Japanese population was similar to that in other Asian surveys but higher than in black or white populations. Our study confirmed a higher prevalence of myopia among younger vs. older populations, and a significant association with education levels and socioeconomic factors.

The relationship between age and intraocular pressure in a Japanese population: The influence of central corneal thickness

Purpose. Previous cross-sectional Japanese studies have shown that intraocular pressure (IOP) decreases with age. However, central corneal thickness (CCT) variation should also be considered when examining the relationship between age and IOP, since tonometry has an inherent measurement error due to CCT variations. This study investigates the influence of CCT variation on the age-IOP relationship in a Japanese population. Methods. The right eyes of 1317 subjects from 40 to 80 years old selected from a general population using a random sampling method were assessed in cross-section. The IOP was measured with a non-contact tonometer, and CCT was measured with a specular microscope. The relationships between age, IOP, and CCT were assessed using correlation analyses, while the relationship between age and IOP controlled for CCT, blood pressure, and body mass index was investigated using multivariate regression analyses. Results. The mean (± SD) IOP value was 13.6 (± 2.6) mmHg in men and 13.3 (± 2.6) mmHg in women. The IOP correlated inversely with age in men (r = -0.14, p <0.001), but showed only a marginal inverse correlation in women (r = -0.07, p = 0.066). The mean (± SD) CCT value was 518.3 (± 33.2) µm in men and 511.1 (± 33.0) µm in women. Only in men was an inverse correlation seen between CCT and age (r = -0.10, p = 0.009), but both genders had positive correlations between CCT and IOP (man: r = 0.44, p < 0.001; woman: r = 0.48, p < 0.001). In multivariate analyses, CCT was shown to have an effect on IOP measurement, however, it was shown that IOP still decreases with age in both sexes even when adjusted for CCT (p = 0.001). Conclusions. The IOP decreases with age in the Japanese, and CCT variation has practically no effect on the unique age-IOP relationship.

Age-related Change in Contrast Sensitivity Among Japanese Adults

PURPOSE To evaluate the age-related change in contrast sensitivity seen in a middle-aged to elderly Japanese population. METHODS Contrast sensitivity and visual acuity were measured in subjects aged 40 to 79 years randomly recruited from a community in Aichi prefecture near Nagoya, Japan. Contrast sensitivity tests were performed using the Vistech contrast sensitivity test chart (VCTS 6500). The results were statistically analyzed relative to age. RESULTS A statistically significant decrease in contrast sensitivity was seen with advancing age at each spatial frequency (Cochran-Mantel-Haenszel: P<.001). This trend was detected even when the subjects were limited to only those having a corrected visual acuity of 1.0 or better (Cochran-Mantel-Haenszel: P<.001). Overall, 9.4% of the eyes with good visual acuity had poor contrast sensitivity at a high spatial frequency, while in the 70-79-year-old group, the percentage with poor contrast sensitivity reached 21.1%. CONCLUSIONS The age-related decrease in contrast sensitivity was confirmed at all frequencies in our population, even when adjusted for visual acuity. Our results suggest that contrast sensitivity tests, especially at high frequencies, assess aspects of visual function that cannot be determined in the elderly population from visual acuity tests alone.

Vitrectomy for diabetic macular edema: Effect of glycemic control (HbA1c), renal function (creatinine) and other local factors

Aims: To determine the effect of preoperative factors on the foveal thickness following vitrectomy for diabetic macular edema. Methods: Fifty-eight eyes of 47 patients underwent vitrectomy for diabetic macular edema. In all eyes, no clear, visible vitreomacular traction was present. Twelve eyes were pseudophakic before vitrectomy, and 31 eyes underwent concurrent phacoemulsification and intraocular lens (IOL) implantation. Multiple logistic regression analysis was used to assess the independent effect of age, history of photocoagulation, diabetic retinopathy status, preoperative posterior vitreous detachment, HbA1c and serum creatinine levels within 2 weeks before surgery, lens status after surgery and follow-up period on the foveal thickness determined by optical coherence tomography. Results: The median preoperative visual acuity was 20/100 (range from 20/500 to 20/20), and the median postoperative visual acuity was 20/70 (range from 20/500 to 20/13). The preoperative visual acuity (logarithm of minimal angle of resolution; logMAR) was 0.73 ± 0.36 (mean ± SD; 20/107 Snellen acuity), and the mean postoperative logMAR visual acuity was 0.60 ± 0.39 (20/80), which was significantly better than the mean preoperative value (Wilcoxon signed rank test, p = 0.011). The mean ± SD of preoperative foveal thickness was 475.9 ± 172.5 µm, and the mean postoperative foveal thickness was 277.3 ± 171.9 µm. The mean postoperative foveal thickness was significantly thinner than the preoperative thickness (Student’s paired t test, p < 0.0001). Multiple logistic regression analysis showed that a preoperative low HbA1c and postoperative pseudophakia were independently associated with the decrease in foveal thickness (p = 0.01, p = 0.04, respectively). Conclusions: The greater reduction in foveal thickness in eyes with an IOL probably resulted from a relatively larger amount of vitreous being removed during the vitrectomy. Because the decrease in foveal thickness may be related to the preoperative glycemic control and the amount of vitreous, these factors should be considered in the planning for vitrectomy.

The impact of arterial sclerosis on hearing with and without occupational noise exposure: A population-based aging study in males

OBJECTIVES Arterial sclerosis contributes to inadequate blood supply to multiple organs, suggesting that general atherosclerosis may play an important role in the inner ear. Since noise is a major etiology for hearing loss, the aim of this study was to evaluate both the respective and the combined effects of arterial sclerosis and occupational noise exposure on hearing after accounting for age in middle-aged and elderly men. METHODS The evaluation was conducted using 773 subjects from a population-based sample of 1189 men, aged 40-83 years. The impact of carotid atherosclerosis (CA) or retinal arteriolosclerosis (RA) on hearing was assessed according to history of occupational noise exposure (Noise) obtained in a questionnaire. Differences in the mean pure-tone thresholds at each frequency, between the CA (+) and CA (-) groups or between the RA (+) and RA (-) groups, based on noise exposure were compared using the general linear model (GLM) Procedure in SAS, with adjustments for age. Then, the main effect of CA or RA, and the interactive effect of noise and either CA or RA on pure-tone threshold at seven frequencies were analyzed using an analysis of covariance (ANCOVA), after adjusting for age. RESULTS In the Noise (+) group, a statistically significant deterioration in hearing was found in the CA (+) group compared with the CA (-) group at 500 and 1000 Hz. The results in RA were significant at even lower frequencies than in CA. In the results from ANCOVA, the significant main effect of CA was shown in the pure-tone threshold at 8000 Hz, but not in the analysis of RA. A significant interactive effect of either CA or RA and Noise was observed in hearing at the range from 125 to 1000 Hz. CONCLUSIONS The present study suggests that the impact of arterial sclerosis on hearing is limited but significantly hazardous in middle-aged and elderly men, and that arterial sclerosis exacerbates the deleterious effects of noise on hearing. Early recognition of arterial sclerosis might be contributory to the hearing prognosis after middle age, especially for noise-exposed men.

Estimation of anterior nucleus of lens by Scheimpflug image before and after pupil dilatation

PURPOSE To compare the accuracy of lens transparency evaluations by Scheimpflug image in the anterior nucleus of the lens before and after pupil dilatation. METHODS Scheimpflug lens images were recorded in 70 eyes of 38 subjects (age: 28-75 years) before and after pupil dilatation, and light scattering intensity measurements before and after dilatation were compared. RESULTS There was a significant positive correlation between the light scattering intensity before and after dilatation at the anterior cortex, anterior nucleus, and central clear zone of the lens (r > 0.9, P <.0001). CONCLUSIONS It is possible to estimate the transparency in the anterior nucleus of the lens from the Scheimpflug image without pupil dilatation. If nuclear type cataracts are regarded as a structural marker of aging in epidemiological studies, measuring the light scattering intensity in the anterior nucleus of the lens without dilatation seems to be a safe, useful, and quantitative method.