Akio Tabuchi

Influence of three-dimensional image viewing on visual function

PurposeA three-dimensional (3D) image viewing experiment was performed using a new 3D scenography system. The influence on visual function was investigated both in adults and in children employing both objective and subjective methods.MethodsThe subjects were 21 healthy adults (mean age ± standard deviation: 42.1 ± 10.0 years) and 21 healthy children (7.8 ± 1.5 years). The 3D image viewing time was set at 90 min for adults and 60 min for children, and the visual function was objectively evaluated using an accommodative microfluctuation analysis system both before and after 3D image viewing. In addition, subjective symptoms were surveyed employing a questionnaire both before and after viewing in the adult group to subjectively evaluate the visual function.ResultsNo significant difference was noted in accommodative microfluctuation between the before and after viewing in either the adult or child group, nor was there a significant difference in subjective symptoms in the adult group based on the questionnaire. However, accommodative microfluctuation tended to increase after viewing in some subjects.ConclusionsUnder the conditions of this study, 3D image viewing did not influence visual function, or only very slightly influenced it, if at all, but there are many unknown problems, requiring further surveys using 3D image viewing.

Retinal Ganglion Cell Atrophy in Homonymous Hemianopia due to Acquired Occipital Lesions Observed Using Cirrus High-Definition-OCT

Purpose. To report a reduction in macular ganglion cell layer and inner plexiform layer (GCL+IPL) thickness and circumpapillary retinal nerve fiber layer (cpRNFL) thickness using spectral-domain optical coherence tomography in patients with homonymous hemianopia due to posterior cerebral artery (PCA) stroke. Methods. Seven patients with PCA stroke were examined using Cirrus high-definition-OCT. The GCL+IPL thicknesses were divided into the hemianopic and unaffected sides. The relationship between the time after stroke and the GCL+IPL thicknesses in the hemianopic side was evaluated. Results. The average thicknesses of the GCL+IPL were 64.6 and 82.0 μm on the hemianopic and unaffected sides, respectively, and the measurement was significantly thinner on the former side (p = 0.018). A regression analysis revealed a negative linear relationship (R 2 = 0.574, p = 0.049) between the time after stoke and the GCL+IPL thicknesses on the hemianopic side. The supratemporal and inferotemporal cpRNFL thicknesses in the eyes ipsilateral to the stroke showed a significant reduction. Conclusion. Our findings confirmed our previous observations that the degeneration of retinal ganglion cells can occur after PCA stroke. GCL+IPL thinning was demonstrated in the hemiretinae corresponding to the affected hemifields. Also, it is suggested that the retinal changes observed are progressive.

Multiple Comparisons for a Psychophysical Test in Bootstrap Logistic Regression

We propose an algorithm of multiple comparisons with a control for a psychophysical test. Our algorithm is based on the step-down procedure and is applicable to the bootstrap test in logistic regression. We use logistic regression combined with guessing rate and log-likelihood ratio test statistics of multiple samples in order to test hypotheses by using non-parametric bootstrap resampling. We apply our algorithm to visual acuity measurement, and show that bootstrap resampling can be used to resolve problems with multiple comparisons especially when the numbers of observations among samples are not identical.

Telemedicine system using 3 - D high definition image

We developed a telemedicine support system with which the transmission of 3D high definition images is possible. The trial was carried out using pigs eyes. Each step in this operation took place through an ophthalmologists instructions to the operator who had no experience with cataract operations. In the end, we had highly successful results on delivery of the image and voice. The operation went smoothly without stopping. This system can smoothly deliver huge volumes of data at low-cost, and would be a useful system for telemedicine. Operators to viewing time with no asthenopia more than some hours it was possible for view 3D high definition image.

A pupil perimeter for objective visual field measurement

We developed a new pupil perimeter which consisted of a 19 inch liquid crystal display for stimulations and an infrared CCD camera for recording the pupillary light reflex. An LCD increases the flexibility of size, luminance, frequency and color of the stimulations compared with that of using conventional perimeter. And we devised another type pupil perimeter using head mount display. It was expected to contribute space savings and easy measuring for old people and bedridden patients. We considered that a pupil perimeter could be used in clinical applications for evaluating an objective visual field easily. Furthermore, pupil perimetry may be useful for detecting in glaucomatous visual field defects.

Preferential atrophy of the central retinal ganglion cells in homonymous hemianopia due to acquired retrogeniculate lesions demonstrated using swept-source optical coherence tomography

Department of Sensory Science, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Kurashiki, Okayama, Japan; Department of Ophthalmology, Kawasaki Medical School, Okayama, Japan; Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan; Department of Neurological Science, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan; Department of Stroke Medicine, Kawasaki Medical School, Okayama, Japan

Multiple comparisons in two-factor testing of psychophysical thresholds by the delta test method

Abstract We propose an algorithm of multiple comparisons in two-factor testing of psychophysical thresholds. We use logistic regression combined with guessing rate and adopt the step-down procedure with Ryan–Einot–Gabriel–Welsch (REGW) significance levels for multiple test. We test hypotheses of main effects and interaction in two-factor problem by using the delta test statistics.

Repeatability of visual acuity testing using a psychometric function

AbstractPurpose To evaluate the repeatability of a new method of measurement of visual acuity by use of a psychometric function.MethodsThe visual acuity of 15 healthy adults was measured by use of a psychometric function (PFVA) and by use of a conventional method using a decimal visual acuity chart (DeVA). We performed two tests. To evaluate intra-rater reliability, a tester measured the visual acuity three times for each subject, and the intraclass correlation coefficients, ICC (1,1), were calculated for PFVA and DeVA. Next, to evaluate inter-rater reliability, three testers measured the visual acuity for one subject, and the ICC (2,1) were calculated for PFVA and DeVA. The PFVA and DeVA of five subjects with ocular diseases were also measured.ResultsIn the evaluation of intra-rater reliability, the ICC (1,1) of the DeVA was 0.83 and the ICC (1,1) of the PFVA was 0.95. In the evaluation of inter-rater reliability, the ICC (2,1) of the DeVA was 0.88 and the ICC (2,1) of the PFVA was 0.93. In both tests the standard deviations of the PFVA were significantly lower than those of the DeVA. For four of the five subjects with ocular diseases, the PFVA was significantly improved by treatment.ConclusionThe repeatability of our method is better than that of the conventional method using a decimal visual acuity chart.