Masakazu Yamada

Prof. Dr. Masakazu Yamada

orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 August 2018 in Ophthalmology
Verified
Journal Article
Closed access
CVChi Hoang Viet Vu
Chi Hoang Viet Vu
MKMotoko Kawashima
Motoko Kawashima
MYMasakazu Yamada
Masakazu Yamada
KSKazuhisa Suwaki
Kazuhisa Suwaki
MUMiki Uchino
Miki Uchino
Kazuo TsubotaKazuo Tsubota
Kazuo Tsubota

27 April 2022 in Diagnostics
Verified
Journal Article
Open access
PDF file
TWTomoyuki Watanabe
Tomoyuki Watanabe
YHYoshimune Hiratsuka
Yoshimune Hiratsuka
YKYoshiyuki Kita
Yoshiyuki Kita
HTHiroshi Tamura
Hiroshi Tamura
RKRyo Kawasaki
Ryo Kawasaki
MYMasakazu Yamada
Masakazu Yamada
We aimed to evaluate the accuracy of glaucoma screening using fundus photography combined with optical coherence tomography and determine the agreement between ophthalmologists and ophthalmology residents. We used a comprehensive ophthalmologic examination dataset obtained from 503 cases (1006 eyes). Of the 1006 eyes, 132 had a confirmed glaucoma diagnosis. Overall, 24 doctors, comprising two groups (ophthalmologists and ophthalmology residents, 12 individuals/group), analyzed the data presented in three screening strategies as follows: (1) fundus photography alone, (2) fundus photography + optical coherence tomography, and (3) fundus photography + optical coherence tomography + comprehensive examination. We investigated the diagnostic accuracy (sensitivity and specificity). The respective sensitivity and specificity values for the diagnostic accuracy obtained by 24 doctors, 12 ophthalmologists, and 12 ophthalmology residents were as follows: (1) fundus photography: sensitivity, 55.4%, 55.4%, and 55.4%; specificity, 91.8%, 94.0%, and 89.6%; (2) fundus photography + OCT: sensitivity, 80.0%, 82.3%, and 77.8%; specificity, 91.7%, 92.9%, and 90.6%; and (3) fundus photography + OCT + comprehensive examination: sensitivity 78.4%, 79.8%, and 77.1%; specificity, 92.7%, 94.0%, and 91.3%. The diagnostic accuracy of glaucoma screening significantly increased with optical coherence tomography. Following its addition, ophthalmologists could more effectively improve the diagnostic accuracy than ophthalmology residents. Screening accuracy is improved when optical coherence tomography is added to fundus photography.

13 October 2014 in Current Eye Research
Verified
Journal Article
Closed access
PDF file
CSChika Shigeyasu
Chika Shigeyasu
SHShinichiro Hirano
Shinichiro Hirano
YAYoko Akune
Yoko Akune
MYMasakazu Yamada
Masakazu Yamada
Purpose: This study was undertaken to determine the effect of topical application of diquafosol tetrasodium on proteins and mucin-like substances from tears of clinically healthy subjects. Methods: Tears were collected from both the eyes of 10 healthy volunteers. Diquafosol tetrasodium solution (3%) was applied once to the right eye and 0.9% sodium chloride solution (saline) once to the left eye. Tear samples were collected by Schirmer test strips before application and 5, 15, 30 and 60 min after application. Sialic acid, a marker of mucin-like substances, and major tear proteins including secretory IgA, lactoferrin, lipocalin-1, and lysozyme were measured by high performance liquid chromatography. Results: Levels of total protein, sIgA and lysozyme were transiently decreased in both groups but returned to baseline levels within 15 min after application. The concentration of lactoferrin and lipocalin-1 did not change significantly in both groups. Sialic acid in tears was significantly decreased 5 min after saline application, but significantly increased 5 min after diquafosol application. No significant difference in sialic acid was seen after 15 min in both groups. Conclusions: Topical application of saline and diquafosol resulted in transient decrease of tear proteins possibly due to wash out or dilution effects. In contrast, diquafosol application significantly increased sialic acid, although the effect was transient. This suggests diquafosol stimulates the secretion of mucins from ocular tissues of healthy human subjects.

2 January 2015 in Current Eye Research
Verified
Journal Article
Closed access
PDF file
MFMasaki Fukui
Masaki Fukui
MYMasakazu Yamada
Masakazu Yamada
YAYoko Akune
Yoko Akune
CSChika Shigeyasu
Chika Shigeyasu
KTKazuo Tsubota
Kazuo Tsubota
Purpose: Unstable tear film characterized by shorting of tear break-up time (BUT) is associated with discomfort and dryness in contact lens wearers. The glycocalyx is thought to be crucial in maintaining the wettability and lubrication of the ocular surface. We evaluated the ocular surface glycocalyx in soft contact lens (SCL) wearers using a fluorescein-labeled wheat germ agglutinin (F-WGA) as a marker to demonstrate the ocular surface glycoconjugates in vivo. Methods: Twenty experienced SCL wearers and 20 healthy volunteers with no history of CL wearing (controls) were enrolled in the study. After applying a 5% F-WGA solution to the eyes of study individuals, fluorescent intensities in their respective central corneas were measured by fluorophotometry. The relationship between F-WGA intensity in the corneal surface and clinical parameters associated with contact lens wear were analyzed. Results: F-WGA fluorescence intensity in the SCL group was 418.5 ± 103.3, which was significantly lower than that of the controls (825.0 ± 179.8; p < 0.0001, Mann–Whitney test). F-WGA fluorescence intensity was not correlated with Schirmer’s test values or age, whereas a statistically significant correlation between F-WGA fluorescence intensity and tear film BUT was observed (r = 0.77, p < 0.0001). The decrease in F-WGA fluorescence intensity could be reversed by discontinuation of SCL use. Conclusion: Reduction and/or compositional alteration of ocular surface glycocalyx may be one of the causative factors of SCL-induced eye dryness.

Verified
Journal Article
Open access
PDF file
MKMotoko Kawashima
Motoko Kawashima
MYMasakazu Yamada
Masakazu Yamada
CSChika Shigeyasu
Chika Shigeyasu
KSKazuhisa Suwaki
Kazuhisa Suwaki
MUMiki Uchino
Miki Uchino
FGfor the DECS-J Study Group
for the DECS-J Study Group
We investigated the association between dry eye disease and systemic comorbidities, including dry eye subtype, quality of life (QOL) and health utility among patients with dry eye disease. This cross-sectional, observational study enrolled 449 patients with dry eye disease (386 females; mean age, 62.6 ± 15.7 [range, 21–90] years). Ophthalmic examination findings included tear film break-up time (TBUT), Schirmer I value and keratoconjunctival staining score. QOL and health utility were evaluated using the Dry Eye-Related Quality-of-Life Score (DEQS) and Human Utility Index Mark 3 (HUI-3), respectively. Background information, including systemic comorbidities, was obtained. Prevalence of systemic comorbidities was 48.8% (219/449). No significant difference occurred between DEQS and systemic comorbidity. However, patients with dry eye disease and systemic comorbidities (depression and insomnia) exhibited significantly worse ocular surface parameters, particularly regarding TBUT, than those without. Dry eye disease with insomnia or depression comorbidity significantly correlated with friction-related diseases (including conjunctivochalasis or lid wiper epitheliopathy). A high prevalence of several systemic comorbidities occurred in patients with dry eye disease. This study shows an association between ocular signs and systemic comorbidities, particularly depression and insomnia. Ophthalmologists should be aware of patients’ systemic comorbidities in the diagnosis and management of dry eye disease.

31 August 2018 in Health and Quality of Life Outcomes
Verified
Journal Article
Open access
PDF file
CSChika Shigeyasu
Chika Shigeyasu
MYMasakazu Yamada
Masakazu Yamada
MKMotoko Kawashima
Motoko Kawashima
KSKazuhisa Suwaki
Kazuhisa Suwaki
MUMiki Uchino
Miki Uchino
Kazuo TsubotaKazuo Tsubota
Kazuo Tsubota
To determine whether quality of life (QOL) and health utility are affected to the same extent among dry eye (DE) patients with short tear film break-up time dry eye (TBUT-DE) with minimal clinical signs were as severe as aqueous-deficient dry eye (ADDE). A multicenter cross-sectional study was conducted among DE patients who visited one of 10 eye clinics in Japan. Among the 463 registered patients, this study involved 449 patients with DE who were aged 20 years or older. Ophthalmic examination findings were assessed, including tear film break-up time (TBUT), Schirmer I value, and keratoconjunctival staining score. QOL was evaluated with the Dry Eye-Related Quality-of-Life Score (DEQS; 0 [best], 100 [worst]) and health utility (1 [total health], 0 [worst]) with the Health Utilities Index Mark 3 (HUI-3); scores were stratified by DE subgroup. Median (interquartile range) of DEQS and HUI-3 scores across all participants were 21.7 (10.0–40.0) and 0.82 (0.69–0.91), respectively. Median (interquartile range) DEQS and HUI-3 scores in the ADDE group were 23.3 (10.0–40.0) and 0.79 (0.69–0.88), respectively; those in the short TBUT-DE group were 23.3 (13.3–38.3) and 0.82 (0.74–0.92), respectively. There were no significant between-group differences in questionnaire scores. Among the ophthalmic examination findings, a weak significant correlation between TBUT, corneal staining score and keratoconjunctival staining score to DEQS; TBUT and Schirmer test values to HUI-3, were seen. The burden of short TBUT-DE on QOL as assessed by the DEQS and HUI-3 was as severe as that in ADDE. Our findings suggest that clinicians should be aware of the impact of short TBUT-DE on patients QOL and utility values. University Hospital Medical Information Network (registration no. UMIN 000015890). Registered 10th December 2014, retrospectively registered.