Tsutomu Yamashita

Central and peripheral intraocular pressure measured by a rebound tonometer.

Purpose: We investigated at which corneal region the intraocular pressure as measured by the Icare® rebound tonometer (Finland Oy, Espoo, Finland) (hereinafter referred to as IC) was closest to the intraocular pressure as measured by the Goldmann applanation tonometer (hereinafter referred to as GT). We also investigated which parameters would be best for preparing the most suitable model for predicting GT. Methods: A total of 102 normal eyes in 102 subjects were enrolled. IC measurements were carried out at the central, superior, inferior, temporal, and nasal regions of the cornea (ICC, ICS, ICI, ICT, and ICN, respectively), followed by GT calculations. Differences between GT and IC were analyzed using the Bland–Altman method. Stepwise multiple regression analysis was performed using GT as the objective variable, and age, laterality of eye, spherical equivalent refractive error, corneal radius, axial length, central corneal thickness, GT, ICC, ICS, ICI, ICT, and ICN as the explanatory variables. Results: IC was higher than GT at all of the corneal regions, but the region with the least bias was ICC, followed by ICT. In the multiple regression analysis, the following prediction formula was calculated: GT = (0.445 × ICC) + (0.198 × ICN) + 3.022. When ICC was excluded from the explanatory variables, ICT had the highest partial correlation coefficient with GT. Conclusion: ICC was closest to GT, but GT could be explained better by adding ICN to the prediction model. Moreover, in instances where ICC cannot be calculated or where reliability is clearly poor due to abnormal ocular rigidity, ICT was the closest to GT measured in the central corneal region.

a comparison between amblyopic and fellow eyes in unilateral amblyopia using spectral-domain optical coherence tomography

Purpose To compare the macular retinal thickness and characteristics of optic nerve head (ONH) parameters in amblyopic and fellow eyes in patients with unilateral amblyopia. Patients and methods A total of 21 patients with unilateral amblyopia (14 patients with anisometropic amblyopia, four patients with strabismic amblyopia, and three patients with both) were examined using spectral-domain optical coherence tomography. The mean age of the patients was 8.5±3.5 years. The examined parameters included the mean macular (full, inner, and outer), ganglion cell complex and circumpapillary retinal nerve fiber layer (cpRNFL) thicknesses, and ONH parameters (rim volume, nerve head volume, cup volume, rim area, optic disc area, cup area, and cup-to-disc area ratio). Results The amblyopic eyes were significantly more hyperopic than the fellow eyes (P<0.001). Among the macular retinal thickness parameters, the cpRNFL thickness (P<0.01), macular full retinal thickness (3 mm region) (P<0.01), and macular outer retinal thickness (1 and 3 mm regions) (P<0.05) were significantly thicker in the amblyopic eyes than in the fellow eyes, while the ganglion cell complex thickness, macular full retinal thickness (1 mm region), and macular inner retinal thickness (1 and 3 mm regions) were not significantly different. Among the ONH parameters, the rim area was significantly larger and the cup-to-disc area ratio was smaller in the amblyopic eyes than in the fellow eyes (P<0.05). None of the other ONH parameters were significantly different between the investigated eyes. The differences in the cpRNFL thickness and macular outer retinal thickness in the 1 mm region were significantly correlated with the difference in axial length (P<0.05, r=−0.48; P<0.01, r=−0.59, respectively) and refractive error (P<0.05, r=0.50; P<0.01, r=0.60, respectively). The other parameters were not significantly related to the difference in axial length, refractive error, or best corrected visual acuity. Conclusion We found significant differences in some of the morphological measurements between amblyopic and fellow eyes that appear to be independent of abnormalities in the visual cortex.

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.

Quantitative Analysis of Macular Inner Retinal Layer Using Swept-Source Optical Coherence Tomography in Patients with Optic Tract Syndrome

Objective To evaluate macular inner retinal layers using swept-source optical coherence tomography (SS-OCT) in patients with homonymous hemianopia due to optic tract syndrome (OTS). Methods Sixteen eyes of 8 patients with OTS were studied. The macular retinal nerve fiber layer (mRNFL), ganglion cell layer and inner plexiform layer (GCL + IPL), and mRNFL and GCL + IPL (GCC) were measured by SS-OCT (DRI OCT-1 Atlantis®).The scanned area was divided into eight regions and two hemiretinae. Each retinal thickness of the OTS group was compared with that of the 25 control subjects. Results The GCC thickness in the ipsilateral eyes was significantly reduced in all regions, although predominant thinning of the GCC in the contralateral eyes was found in the nasal region. The GCC + IPL thickness was preferentially reduced at the temporal regions in the ipsilateral eyes and at the nasal regions in the contralateral eyes. The reduction rate of the GCL + IPL thickness was 29.6% at the temporal hemiretina in the ipsilateral eyes and 35.2% at the nasal hemiretina in the contralateral eyes. Conclusion We found preferential loss of the GCC + IPL thickness corresponding to the hemifield defects in each eye. Quantitative analysis by SS-OCT is capable of detecting the characteristic RGC loss due to OTS.

Macular retinal and choroidal thickness in unilateral amblyopia using swept-source optical coherence tomography

BackgroundTo investigate macular retinal and choroidal thickness in amblyopic eyes compared to that in fellow and normal eyes using swept-source optical coherence tomography (SS-OCT).MethodsThis study examined 31 patients with hyperopic anisometropic amblyopia (6.9 ± 3.8 years, mean ± standard deviation), 15 patients with strabismic amblyopia without anisometropia (7.9 ± 4.2 years), and 24 age-matched controls (7.8 ± 3.3 years). Retinal and choroidal thickness was measured by 3D scans using SS-OCT. A 6-mm area around the fovea was automatically analyzed using the Early Treatment Diabetic Retinopathy Study map. The thickness from SS-OCT was corrected for magnification error using individual axial length, spherical refraction, cylinder refraction, and corneal radius. Retinal thickness was divided into the macular retinal nerve fiber layer (mRNFL), ganglion cell layer + inner plexiform layer (GCL+IPL), ganglion cell complex (GCC), and the inner limiting membrane to the retinal pigment epithelium (ILM-RPE) thickness. Retinal and choroidal thickness was compared among amblyopic, fellow, and normal eyes.ResultsIn both amblyopia groups, there was no significant difference in the mRNFL, GCL+IPL, and GCC thicknesses among the amblyopic, fellow, and control eyes. In the anisometropic amblyopia group, choroidal thickness (subfovea, center 1 mm, nasal and inferior of the inner ring, nasal of the outer ring, and center 6 mm) of amblyopic eyes were significantly greater than that of fellow and normal eyes. In contrast, none of the choroidal thicknesses were significantly different among the investigated eyes in the strabismic amblyopia group.ConclusionsWe found no significant difference in inner retinal thickness in patients with unilateral amblyopia. Although there were significant differences in choroidal thickness with hyperopic anisometropic amblyopia, there was no significant difference for the strabismic amblyopia. The discrepancy in choroidal thickness between the two types of amblyopia may be due to both differences in ocular size and underlying mechanism.

Relative Afferent Pupillary Defects in Homonymous Visual Field Defects Caused by Stroke of the Occipital Lobe Using Pupillometer

ABSTRACT Relative afferent pupillary defects (RAPD) may be detected in patients with occipital lobe lesions. However, no previous report has used an objective technique to record the abnormal pupillary light reflex in such cases. Therefore, we measured the pupillary light reflex objectively in 15 patients with homonymous visual field defects (HVFD) due to occipital stroke using a new pupillometer. This study detected significantly smaller and slower pupillary light reflexes in the contralateral eyes than in the other eyes, which is equivalent to the presence of RAPD in patients with HVFDs caused by retrogeniculate lesions using an objective technique. Our results confirmed those of the previous reports using the swinging flashlight test more objectively.

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