Atsuo Tomidokoro

Refractive Errors in an Elderly Japanese Population: The Tajimi Study

PURPOSE To evaluate the prevalence of refractive errors associated with age, gender, and central corneal thickness and to evaluate astigmatism in the refraction and keratometry in a randomly sampled elderly Japanese population. DESIGN Population-based epidemiologic survey. PARTICIPANTS A random sampling of residents of Tajimi, Japan, aged 40 years or older. A total of 3021 residents (participation rate, 78.1%) participated. METHODS Each subject underwent screening examinations including autokeratorefractometry, subjective refraction, best-corrected visual acuity, central corneal thickness measurement, intraocular pressure measurement, slit-lamp examination, fundus photography, and visual field testing. MAIN OUTCOME MEASURES The prevalence of myopia (spherical equivalent [SE], <-0.5 diopters [D]), high myopia (SE, <-5 D), hyperopia (SE, >0.5 D), refractive astigmatism (cylinder, >0.5 D), and anisometropia (difference in SE between eyes, >1.0 D), and the correlation of refractive errors with age, gender, and central corneal thickness. Astigmatism in the refraction and keratometry was analyzed using polar value analysis and the vector calculation method. RESULTS The crude prevalence of myopia, high myopia, hyperopia, refractive astigmatism in the refraction, and anisometropia was 41.8% (95% confidence interval [CI], 40.0%-43.6%), 8.2% (95% CI, 7.2%-9.2%), 27.9% (95% CI, 26.3%-29.6%), 54.0% (95% CI, 52.1%-55.8%), and 15.1% (95% CI, 13.7%-16.4%), respectively. The prevalence of myopia decreased with age up to 70 to 79 years but increased slightly in patients 80 years and older; the prevalence of hyperopia showed the opposite trend. The prevalence of astigmatism and anisometropia was higher in the older age groups. No significant gender difference was found associated with the refractive status except for keratometric readings. Polar value analysis and the vector calculation method showed a trend toward against-the-rule astigmatism with increasing age in both refractive and keratometric astigmatism, with a discrepancy between the two. CONCLUSIONS The overall prevalence of myopia (SE, <-0.5 diopters) was 41.8% in the study population, which is higher than that in population-based studies previously reported.

Changes in anterior and posterior corneal curvatures in keratoconus.

OBJECTIVE To quantitatively evaluate the changes in anterior and posterior corneal curvatures of eyes with keratoconus. DESIGN Case-control retrospective and observational study. PARTICIPANTS Thirty-one patients who were clinically diagnosed to have unilateral or bilateral keratoconus and 18 normal subjects. INTERVENTION The anterior and posterior topographies were obtained using scanning-slit videokeratography and assessed by Fourier series harmonic analysis. MAIN OUTCOME MEASURES Quantitative descriptors of the topography data, spherical power, regular astigmatism, and irregular astigmatism (asymmetry and higher order irregularity) components were compared between the anterior and posterior surfaces and among groups of clinically diagnosed keratoconus (33 eyes), keratoconus suspect (13 eyes), and normal subjects (36 eyes). RESULTS Spherical power (P = 0.0003, Mann-Whitney U test with Bonferronis correction of P values), regular astigmatism (P = 0.0166), and asymmetry (P = 0.0031) of the anterior surface were significantly greater in the keratoconus eyes than in the normal controls. For the posterior surface, spherical power (P<0.0001), regular astigmatism (P = 0.0143), asymmetry (P< 0.0001), and higher order irregularity (P = 0.0032) of the keratoconus group were significantly greater than those of the control group. The keratoconus suspect eyes, when compared with the normal controls, showed a significantly greater amount of spherical power (P = 0. 0166) and asymmetry (P<0.0001) in the anterior surface and spherical power (P <0.0001), regular astigmatism (P = 0.0244), asymmetry (P<0.0001), and higher order irregularity (P = 0.0276) in the posterior surface. All refractive components demonstrated statistically significant correlations between the anterior and posterior surfaces (P<0.0001, Spearmans rank correlation). CONCLUSIONS Not only the anterior but also the posterior corneal curvature is affected in keratoconus. These changes are observed from the early stage of this disorder.

Automated layer segmentation of macular OCT images using dual-scale gradient information

A novel automated boundary segmentation algorithm is proposed for fast and reliable quantification of nine intra-retinal boundaries in optical coherence tomography (OCT) images. The algorithm employs a two-step segmentation schema based on gradient information in dual scales, utilizing local and complementary global gradient information simultaneously. A shortest path search is applied to optimize the edge selection. The segmentation algorithm was validated with independent manual segmentation and a reproducibility study. It demonstrates high accuracy and reproducibility in segmenting normal 3D OCT volumes. The execution time is about 16 seconds per volume (480x512x128 voxels). The algorithm shows potential for quantifying images from diseased retinas as well.

Factors affecting the forward shift of posterior corneal surface after laser in situ keratomileusis

PURPOSE To evaluate the anteroposterior movement of the corneal back surface after laser in situ keratomileusis (LASIK). DESIGN Retrospective noncomparative case series. PARTICIPANTS One hundred ninety-six eyes of 120 subjects with myopic refractive errors of -2.0 to -12.5 diopters. INTERVENTION LASIK was performed. Corneal topography of the posterior corneal surface was obtained with the scanning slit topography system before and 1 month after surgery. MAIN OUTCOME MEASURES The amount of forward shift of the posterior corneal surface was determined. Multiple regression analysis was used to assess the factors that affect the forward shift of the posterior corneal surface. RESULTS After surgery, the posterior corneal surface displayed mean forward shift of 40.9 +/- 24.8 micrometer. Explanatory variables relevant to the forward shift of corneal posterior surface were, in the order of magnitude of influence, the amount of laser ablation (partial regression coefficient B = 0.561, P < 0.0001), preoperative corneal thickness (B = -0.176, P = 0.00096), and preoperative intraocular pressure (B = 1.676, P = 0.0053). Preoperative refraction and achieved myopic correction showed collinearity with the amount of laser ablation. CONCLUSIONS LASIK induces a forward shift of the cornea. Eyes with thinner corneas, higher intraocular pressure, and higher myopia requiring greater laser ablation are more predisposed to the anterior shift of the cornea.

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

BackgroundThe 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).MethodsA 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.ResultsBased 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.ConclusionWith 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.

Effects of Age, Sex, and Axial Length on the Three-Dimensional Profile of Normal Macular Layer Structures

PURPOSE To identify sex-related differences and age-related changes in individual retinal layer thicknesses in a population of healthy eyes across the lifespan, using spectral domain optical coherence tomography (SD-OCT). METHODS In seven institutes in Japan, mean thicknesses of the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor inner segment (IS), and photoreceptor outer segment (OS) were measured using SD-OCT with a new automated segmentation protocol in 256 healthy subjects. RESULTS Interoperator coefficients of variability for measurements of each layer ranged from 0.012 to 0.038. The RNFL, GCL, IPL, and INL were thinnest in the foveal area, whereas the OPL+ONL and OS were thickest in this area. Mean thicknesses of the INL and the OPL+ONL were significantly greater in men (P = 0.002 and 0.001, respectively). However, mean RNFL thickness was greater in women (P = 0.006). Thicknesses of the RNFL, GCL, IPL, INL, and IS correlated negatively with age. Thickness of the OPL+ONL was not correlated with age, and thickness of the OS correlated positively with age. Inner retinal (RNFL+GCL+IPL) thickness over the whole macula correlated negatively with age (P < 0.001), but outer retinal (OPL+ONL+IS+OS) thickness did not. Thicknesses of layers did not correlate with axial length. CONCLUSIONS Macular layer thicknesses measured on SD-OCT images in healthy eyes showed significant variations by sex and age. These findings should inform macular layer thickness analyses in SD-OCT studies of retinal diseases and glaucoma.

Proposed Diagnostic Criteria for Obstructive Meibomian Gland Dysfunction

PURPOSE To compare clinical findings between patients with obstructive meibomian gland dysfunction (MGD) and normal controls and to propose diagnostic criteria for obstructive MGD. DESIGN Cross-sectional, observational case series. PARTICIPANTS Fifty-three eyes of 53 patients (18 men, 35 women; age [mean +/- standard deviation] 71.4 +/- 10.0 years) who were diagnosed with obstructive MGD and 60 eyes of 60 healthy volunteers (22 men, 38 women; 71.0 +/- 9.3 years) as a control group. METHODS Ocular symptoms were scored from 0 to 14 according to the number of existing symptoms. Lid margin abnormality was scored from 0 to 4 depending on the number of existing abnormalities. Meibomian gland changes were scored from 0 to 6 based on noncontact meibography (meibo-score). Superficial punctuate keratopathy (SPK) was scored from 0 to 3. Meibum was graded from 0 to 3 depending on the volume and quality. Tear film production was evaluated by Schirmers test. Receiver operating characteristic curves with calculations of area under the curve (AUC) were used to describe the accuracy of each parameter to differentiate obstructive MGD from normal eyes. MAIN OUTCOME MEASURES Ocular symptom score, lid margin abnormality score, meibo-score, meibum score, SPK score, tear film breakup time (BUT), and the Schirmer value. RESULTS Ocular symptom score, lid margin abnormality score, meibo-score, meibum score, and SPK score were significantly higher in the obstructive MGD group than in the control group (P<0.0001 for all scores). The BUT was significantly shorter in the obstructive MGD group than in the control group (P<0.0001). The AUC values indicated that the ocular symptom score had the highest diagnostic power as a single parameter, followed by the lid margin abnormality score, meibo-score, and BUT. CONCLUSIONS Based on these findings, we recommend that physicians use the ocular symptom score, lid margin abnormality score, and meibo-score to diagnose MGD. Obstructive MGD should be suspected when any 2 of the 3 scores are abnormal. Obstructive MGD is very likely when all 3 scores are abnormal.

Real-Time Measurement of Human Optic Nerve Head and Choroid Circulation, Using the Laser Speckle Phenomenon

A modification of a previously described instrument that used the laser speckle phenomenon for noncontact two-dimensional analysis of the fundus tissue circulation was devised so that tissue circulation in the optic nerve head (ONH) or choroid of the human eye could be measured on a real-time basis. The fundus was illuminated by a diode laser spot and the image speckle was recognized by an area sensor. A quantitative index of blood velocity, normalized blur (NB), was calculated by a logistic board every 0.125 seconds for 7 seconds. Using this modified device, the average NB of the measurement field in the temporal ONH, free of visible surface vessels (NBONH), and that in the posterior choroid (NBch) of normal human eyes were measured. The coefficients of reproducibility of 1-minute interval measurements were 11.7% for the NBONH) and 8.7% for the NBch (each, an average of 5 pulses), and those of 24-hour interval measurements were 13.0% (NBONH) and 9.7% (NBch). The pulsatile component average of NBONH was 38.4% of mean NBONH; of NBch, 26.6% of the mean NBch.

Long-term follow-up of visual field progression after trabeculectomy in progressive normal-tension glaucoma.

OBJECTIVE To evaluate the long-term effects of trabeculectomy on the progression of visual field damage in patients with progressive normal-tension glaucoma (NTG). DESIGN Retrospective, noncomparative, interventional case series. PARTICIPANTS Twenty-three patients with NTG who had significant progression of visual field damage preoperatively and underwent trabeculectomy using antimetabolites. METHODS Visual field testing using the Humphrey Visual Field Analyzer was periodically performed before and for at least 5 years after surgery (mean, 6 years). The time course of the mean deviation (MD) and mean of total deviations (TD(mean)) in four separate subfields, superior and inferior cecocentral and superior and inferior arcuate fields, were analyzed using a linear mixed effects model. MAIN OUTCOME MEASURES Intraocular pressure (IOP), preoperative and postoperative regression coefficients of the time course of MD or TD(mean) in the four subfields, corresponding to the rate of progression of visual field damage. RESULTS IOP significantly decreased from 16.2 +/- 1.8 mmHg preoperatively to approximately 11 mmHg during the postoperative follow-up period (P < 0.001). The preoperative regression coefficient of MD change was significantly negative (-1.05 [95% confidence interval, -1.28 to -0.82] dB/year, P < 0.001). After surgery, it increased significantly to -0.44 (95% confidence interval, -0.64 to -0.24) dB/year (P < 0.001), but the postoperative value was still significantly negative (P < 0.001). In the superior cecocentral, superior and inferior arcuate fields, preoperative regression coefficients of TD(mean) change were significantly negative (P < 0.001) and significantly increased after surgery (P < 0.01). In the inferior cecocentral field, the preoperative regression coefficient was not significantly different from 0 (P = 0.72) and did not change significantly after surgery (P = 0.15). CONCLUSIONS Trabeculectomy was statistically associated with slowing further progression of visual field damage in patients with progressive NTG. The progression, however, did not completely stop over the 6-year postoperative follow-up period.

Three-Dimensional Profile of Macular Retinal Thickness in Normal Japanese Eyes

PURPOSE To demonstrate the three-dimensional macular thickness distribution in normal subjects by spectral domain optical coherence tomography (SD-OCT) and evaluate its association with sex, age, and axial length. METHODS Mean regional retinal thickness measurements on the Early Treatment Diabetic Retinopathy Study (ETDRS) layout were obtained by three-dimensional raster scanning (6 x 6 mm) using SD-OCT in 248 normal eyes of 248 Japanese subjects. RESULTS Mean foveal thickness was 222 +/- 19 microm; it was significantly greater in men (226 +/- 19 microm) than in women (218 +/- 18 microm; P = 0.002) and did not correlate with age in either sex. Mean sectoral retinal thickness was also significantly greater in the men than in the women in all the quadrants of the inner ring (1-3 mm; P < 0.001 and P = 0.001-0.007) and in the temporal quadrant of the outer ring (3-6 mm; P < 0.001). The retinal thicknesses of each of the ETDRS sectors did not correlate significantly with axial length after adjustment for age in either sex. Retinal thickness in six of the eight sectors in the inner and outer rings showed a negative correlation with age after adjustment for axial length in the men (P < 0.001 and P = 0.001-0.018), whereas no correlation with age was observed in the women. CONCLUSIONS SD-OCT demonstrated the three-dimensional macular thickness distribution in normal eyes. Macular thickness varied significantly with sex and age. These variables should be considered while evaluating macular thickness.