THTomoaki Higashiyama

Tomoaki Higashiyama

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Tomoaki Higashiyama has a total of 15 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Decreased orbital fat and enophthalmos due to bimatoprost: Quantitative analysis using magnetic resonance imaging

    by Tomoaki Higashiyama, Takayuki Minamikawa, Masashi Kakinoki, Osamu Sawada, Masahito Ohji

    We quantitatively determined the relation between the decrease in orbital fat and enophthalmos due to bimatoprost using magnetic resonance imaging (MRI). Nine orbits in nine patients were treated unilaterally with bimatoprost for glaucoma or ocular hypertension. The contralateral orbits were used as controls. The volumes of the orbital tissues and the enophthalmos were measured using MRI. The mean volumes on the treated and untreated sides were, respectively, 14.6 ± 2.1 and 17.0 ± 4.3 cm3 for orbital fat (P = 0.04) and 3.4 ± 0.5 and 3.3 ± 0.5 cm3 for total extraocular muscles (P = 0.85). The mean enophthalmos values were 14.7 ± 2.5 and 16.0 ± 2.3 mm on the treated and untreated sides, respectively (P = 0.002). The data acquired by quantitatively measuring the volumes of orbital fat and enophthalmos on MRI showed that each might be reduced by bimatoprost administration. The enophthalmos could be caused by the bimatoprost-induced decrease in orbital fat.


  • Open Access

    Treatment with bimatoprost for exophthalmos in patients with inactive thyroid-associated ophthalmopathy

    by Tomoaki Higashiyama, Masahito Ohji

    Treatment with bimatoprost for exophthalmos in patients with inactive thyroid-associated ophthalmopathy Tomoaki Higashiyama, Masahito Ohji Department of Ophthalmology, Shiga University of Medical Science, Otsu, Japan Purpose: This study was performed to observe changes prospectively in exophthalmos and orbital fat in patients with inactive thyroid-associated ophthalmopathy (TAO) treated with bimatoprost. Methods: In this 12-month single-treatment pilot observational study, 13 patients with inactive-phase TAO were administered bimatoprost to treat exophthalmos due to TAO. Exophthalmos values and orbital tissue volumes were measured on MRI by technicians in a masked fashion. Results: Nine orbits of nine patients (eight women, one man) were treated with bimatoprost for 12 months. Mean exophthalmos values before and after treatment were 21.7±2.2 and 21.7±2.0 mm, respectively. The mean value after 12 months of treatment was not significantly different from before treatment (P=0.82). Mean orbital fat volume before and after 12 months of treatment was 17.2±2.5 and 17.0±3.0 cm3, respectively. The corresponding total extraocular muscle volume was 4.0±0.7 and 3.8±0.9 cm3, respectively. Mean volume in each tissue type after 12 months of treatment was not significantly different from before treatment (orbital fat, P=0.70; extraocular muscles, P=0.32). Conclusion: Topical bimatoprost treatment did not reduce exophthalmos or orbital fat in this cohort of patients with inactive TAO. Keywords: bimatoprost, thyroid-associated ophthalmopathy, exophthalmos, orbital fat


  • Open Access

    Comparison of a new biometer using swept-source optical coherence tomography and a conventional biometer using partial coherence interferometry

    by Tomoaki Higashiyama, Hazuki Mori, Fumi Nakajima, Masahito Ohji

    The aim of this study was to compare the axial lengths (ALs) using a new biometer with swept-source optical coherence tomography (Argos) versus ALs using a conventional biometer with partial coherence interferometry (IOL Master, version 5). The ALs in 48 eyes of 48 cataract patients were measured with Argos using refractive indexes that correspond to the particular tissue and with IOL Master using a single refractive index. The eyes were divided into three subgroups by AL length: short-AL group (n = 16), P = 0.002) There was no significant difference in the intermediate-AL groups (P = 0.14). In contrast, the mean ALs with the Argos biometer were shorter than those with the IOL Master biometer in the long-AL group (P < 0.001). Differences between the ALs measured with the two biometers were statistically significant in short- and long-AL subgroups. However, the differences might not be clinically significant.


  • Open Access

    Quantitative Analysis of Inflammation in Orbital Fat of Thyroid-associated Ophthalmopathy Using MRI Signal Intensity

    by Tomoaki Higashiyama, Maki Iwasa, Masahito Ohji

    We quantitatively analyzed inflammation in orbital fat from cases of thyroid-associated ophthalmopathy (TAO) using short-tau inversion recovery (STIR) sequences from magnetic resonance imaging. The signal intensity ratios (SIRs) of orbital fat as well as the superior rectus (SR), inferior rectus (IR), lateral rectus (LR), medial rectus (MR), and superior oblique (SO) muscles on STIR images were measured in 70 eyes from 70 treatment-naive TAO patients (active TAO group, 19 patients; inactive TAO group, 51 patients) and 20 eyes from 20 controls. The mean SIR in the active TAO group was significantly higher than that in the inactive TAO group and controls (P < 0.001). The SIR of orbital fat in all TAO patients was significantly (P < 0.001) positively correlated with that of the extraocular muscles: SR (r = 0.64), IR (r = 0.55), LR (r = 0.58), MR (r = 0.71), and SO (r = 0.65). The SIR of orbital fat had a significant positive correlation with the CAS (r = 0.53, P < 0.001). The measurements of SIRs in orbital fat may be useful in evaluating the activity in tissues of TAO patients.


  • Open Access

    Changes in the anterior segment after cycloplegia with a biometer using swept-source optical coherence tomography

    by Tomoaki Higashiyama, Maki Iwasa, Masahito Ohji

    The aim of this study was to investigate changes in the anterior segment of the eye after cycloplegia. A biometer combined with swept-source optical coherence tomography (SSOCT) was used for measurements. Patients with strabismus or amblyopia who underwent cycloplegia were included. The axial length, central corneal thickness, anterior chamber depth, and lens thickness were measured with the biometer–SSOCT system before and after cycloplegia. Altogether, 10 eyes of 10 patients (mean age 7.20 ± 3.08 years, range 4–14 years) were evaluated. The mean measurements before cycloplegia were 22.75 ± 0.96 mm axial length, 516 ± 33 μm central corneal thickness, 3.40 ± 0.21 mm anterior chamber depth, and 3.77 ± 0.26 mm lens thickness. The corresponding values after cycloplegia were 22.75 ± 0.95 mm, 519 ± 34 μm, 3.68 ± 0.16 mm, and 3.42 ± 0.20 mm, respectively. The mean lens thickness had significantly decreased (P < 0.001) after cycloplegia, and the mean anterior chamber depth had significantly increased (P < 0.001). The means of the axial length (P = 0.66) and central corneal thickness (P = 0.17) had not changed significantly. The change in lens thickness was significantly correlated with the change in anterior chamber depth (r = −0.73, P = 0.02). The new biometer–SSOCT combination proved useful for accurately detecting changes in the anterior segment of the eye after cycloplegia in pediatric patients. The biometer’s measurements indicated increased anterior chamber depth and decreased lens thickness after cycloplegia. The anterior chamber depth increased relative to the decrease in lens thickness.


  • Open Access

    Optical coherence tomography angiography in eyes with good visual acuity recovery after treatment for optic neuritis

    by Tomoaki Higashiyama, Yasuhiro Nishida, Masahito Ohji

    To evaluate the retinal perfusion using optical coherence tomography (OCT) angiography in eyes with good visual acuity recovery after treatment for optic neuritis (ON). Seven eyes of seven patients with good visual acuity recovery after treatment for monocular ON and seven eyes of each fellow eye used as controls were studied. Retinal perfusion around the disc and at the macula was evaluated using OCT angiography. The retinal nerve fiber layer thickness was measured around the disc. The ganglion cell layer complex thickness or the ganglion cell layer plus the inner plexiform layer thickness were measured at the macula. The retinal perfusions in all eyes with ON decreased around the disc and at the macula compared with those of the fellow eyes, as shown by OCT angiography (disc, P = 0.003; macula, P = 0.001). The retinal thicknesses in all eyes with ON also decreased around the disc and at the macula compared with those of the fellow eyes (disc, P < 0.001; macula, P = 0.003). Optic neuritis may cause not only retinal structural damage but also decreased retinal perfusion, even after the visual acuity recovered well after treatment.


  • Optical Coherence Tomography Angiography of Retinal Perfusion in Chiasmal Compression

    by Tomoaki Higashiyama, Yusuke Ichiyama, Sanae Muraki, Yasuhiro Nishida, Masahito Ohji

    BACKGROUND AND OBJECTIVE: To evaluate the retinal perfusion in patients with chiasmal compression using optical coherence tomography angiography (OCTA). PATIENTS AND METHODS: Retinal perfusion was evaluated using OCT angiograms in eight eyes of four patients with visual field (VF) defects due to chiasmal compression treated by tumor resection. The retinal perfusion in the area corresponding to the quadrants of the VF defects was investigated in each image. The vessel density was defined as the percentage area occupied by the vessels in the image. RESULTS: The decreased peripapillary retinal perfusion correlated with the quadrants of the VF defects on OCT angiograms in all patients. The binarized vessel density decreased, corresponding to the degree of VF defects in all patients. CONCLUSIONS: A decrease in peripapillary retinal perfusion correlates with the quadrants of the VF defects due to chiasmal compression. This decrease can be noninvasively measured by OCTA. [ Ophthalmic Surg Lasers Imaging Retina . 2016;47:724–729.]


  • Optical Coherence Tomography Angiography in a Patient with Optic Atrophy After Non-arteritic Anterior Ischaemic Optic Neuropathy

    by Tomoaki Higashiyama, Yusuke Ichiyama, Sanae Muraki, Yasuhiro Nishida, Masahito Ohji

    A 75-year-old female noticed a lower visual field (VF) defect in the right eye. A diagnosis of non-arteritic anterior ischaemic optic neuropathy (NAION) was made. The lower VF defect in the right eye did not change after onset. Optical coherence tomography (OCT) angiograms on the disc and the macula showed decreased retinal perfusion in the upper retina of the right eye. Retinal nerve fibre layer loss and ganglion cell complex loss in the upper retina were also seen in the right eye. OCT angiography could non-invasively detect the decrease of the retinal perfusion due to NAION.


  • Open Access

    Relationship between magnetic resonance imaging signal intensity and volume of extraocular muscles in thyroid-associated ophthalmopathy with methylprednisolone pulse therapy

    by Tomoaki Higashiyama, Yasuhiro Nishida, Masahito Ohji

    Purpose: To characterize the relationship between inflammation and swelling of extraocular muscles in thyroid-associated ophthalmopathy before and after methylprednisolone pulse therapy. Methods: The signal intensities and volumes of the superior rectus (SR), inferior rectus (IR), lateral rectus (LR), medial rectus (MR), and superior oblique (SO) muscles were measured with magnetic resonance imaging in 25 eyes of 25 patients with thyroid-associated ophthalmopathy in the acute inflammatory phase before and after methylprednisolone pulse therapy. The signal intensity ratios (SIRs) of muscles and brain white matter were calculated. Result: The mean SIRs before treatment were 2.28±0.74 in SR, 2.66±0.57 in IR, 2.03±0.42 in LR, 2.45±0.49 in MR, and 1.98±0.48 in SO muscles. The mean SIRs after treatment were 1.82±0.62, 1.84±0.52, 1.70±0.35, 1.95±0.46, and 1.60±0.36, respectively. The mean volumes (cm3) before treatment were 1.35±0.67 in SR, 1.21±0.39 in IR, 0.66±0.13 in LR, 0.94±0.31 in MR, and 0.58±0.14 in SO muscles. Those after treatment were 1.12±0.45, 0.91±0.31, 0.61±0.12, 0.85±0.28, and 0.49±0.11, respectively. The SIRs showed significantly positive correlations with volumes both before and after treatment in SR muscles (before, r=0.77; after, r=0.69), IR muscles (before, r=0.65; after, r=0.60), MR muscles (before, r=0.69; after, r=0.73), and SO muscles (before, r=0.52; after, r=0.50) (PConclusion: Swelling reflected the inflammation in extraocular muscles of thyroid-associated ophthalmopathy both before and after treatment.


  • Changes of orbital tissue volumes and proptosis in patients with thyroid extraocular muscle swelling after methylprednisolone pulse therapy

    by Tomoaki Higashiyama, Yasuhiro Nishida, Masahito Ohji

    To evaluate the changes of orbital tissue volumes and proptosis after methylprednisolone pulse therapy in thyroid-associated ophthalmopathy (TAO).