Tatsuhiko Kobayashi

Background/Objectives: To compare clinical characteristics and visual outcomes of microincision vitrectomy for proliferative diabetic retinopathy (PDR) between urban and rural settings in Japan and examine factors associated with postoperative visual acuity. Methods: This retrospective study included 412 eyes of 312 patients who underwent 25-gauge vitrectomy between December 2020 and December 2025: 142 eyes of 112 patients in the urban setting and 270 eyes of 200 patients in the rural setting. Urban surgeons had 8 and 10 years of experience; the rural surgeon had 25 years. Best-corrected visual acuity (BCVA) was assessed ≥6 months postoperatively. Associations were examined using multivariable linear mixed-effects regression. Results: Compared with eyes in the urban group, those in the rural group had a higher prevalence of tractional retinal detachment (44.4% vs. 30.3%; P = 0.005), better mean postoperative BCVA (0.40 ± 0.67 vs. 0.63 ± 0.78 logMAR; P = 0.004), and a lower proportion with poor postoperative vision (BCVA ≥1.0 logMAR: 14.4% vs. 27.5%; P = 0.001). Higher preoperative intraocular pressure, worse BCVA in the affected and fellow eyes, and macular detachment were associated with worse postoperative BCVA. Vitreous hemorrhage and the combined rural-setting/25-year-surgeon-experience variable were associated with better postopera-tive BCVA (P = 0.0004 and P < 0.0001, respectively). Preoperative neovascular glaucoma also re-mained significant (P = 0.03). Conclusions: The rural group achieved better postoperative vision despite a higher prevalence of tractional retinal detachment. Geographic setting and surgeon expe-rience were confounded; their independent effects cannot be determined. Prospective studies de-signed to distinguish these effects are needed.

Objectives: This study aims to investigate ocular blood flow in male subjects with metabolic syndrome (MetS) using laser speckle flowgraphy (LSFG). Methods: Subjects who underwent LSFG ocular blood flow testing during physical examinations were separated into a MetS group and a control group. The groups were propensity score-matched by age, with 138 male subjects compared in each group. The subjects’ ocular blood flow (mean blur rate, MBR) in the optic nerve head (ONH) and choroid was measured via LSFG. Pulse waveform parameters, the blowout score (BOS), blowout time (BOT), and rising rate (RR), were also measured. The ONH region was measured as a whole and as tissue and vascular regions. Results: The MBR-Choroid was significantly lower in the MetS group versus the control group. There was no significant difference in the MBR in the ONH. Compared to the control group, the RR values in the MetS group were significantly lower in all regions. The whole tissue region and vascular region BOS values were significantly higher in the MetS group. A single-regression analysis revealed that among the evaluated parameters, only the number of MetS components was significantly negatively correlated with the MBR-Choroid. A multiple regression analysis identified HbA1c as a factor contributing independently to the MBR-Choroid among the MetS-related factors. Conclusions: This investigation of adult males clarified that in the early stage of MetS, the MBR in the choroid area decreases in parallel with the accumulation of MetS components. The MetS component with the strongest influence on the MBR-Choroid was HbA1c.

Objectives: To investigate the effects of the ocular blood flow in male subjects with metabolic syndrome (MetS) by using laser speckle flowgraphy (LSFG). Methods: Subjects who underwent LSFG ocular blood flow testing during physical examinations were separated into the MetS group and the control group. The groups were propensity score-matched by age with 138 male subjects compared in each group. The subjects' ocular blood flow values (mean blur rate: MBR) in the optic nerve head (ONH) and choroid were measured by LSFG. We also measured pulse waveform parameters: the blowout score (BOS), blowout time (BOT), and rising rate (RR). The ONH region was measured as a whole, a tissue, and a vascular region. Results: MBR-Choroid was significantly lower in the MetS group versus the control group. For the ONH, there was no significant difference in the MBR. Compared to the control group in all regions, the RR values in the MetS group were significantly lower. The whole, tissue-region, and vascular-region BOS values were significantly higher in the MetS group. A single regression analysis revealed that only the number of MetS components was significantly negatively correlated with MBR-Choroid among the evaluated parameters. A multiple regression analysis identified HbA1c as a factor contributing independently to the MBR-Choroid among the MetS-related factors. Conclusions: This investigation of adult males clarified that the MBR in the choroid area at the early stage of MetS is decreasing in parallel with accumulation of MetS components. The MetS component with the strongest influence to the MBR-Choroid was HbA1c.

Metagenomic analysis is the comprehensive study of DNA using clinical specimens of organisms including bacteria, fungi, and viruses. In this study, we investigated the efficacy of metagenomic analysis for diagnosing ocular infections, including 11 keratitis cases, four iridocyclitis cases, and one endophthalmitis case. Corneal scraping, aqueous humor, and vitreous humor, were collected respectively. Ocular specimens were used for bacterial and fungal culture, and PCR for detecting viral DNA. Shotgun metagenomic sequencing for 150 bases of single end was performed by Illumina MiSeq^® System. Sequence was retrieved from the database at NCBI using a MegaBLAST search. Since Propionibacterium spp. are commensal bacteria found at the ocular surface, they were excluded from analysis. Six cases (37.5%) were positive for culture or PCR. Metagenome techniques revealed that 9 cases (56.3%) included genomes of organisms that were considered pathogenic in specimens. Five cases (31.3%) possessed genomes of organisms like themselves that were detected by culture and PCR. Six cases (37.5%) were negative for culture, PCR, and metagenome analysis. Moreover, viral pathogens (HSV-1, 2 cases; and VZV, 1 case) were detected by only metagenome analysis. Metagenome analysis using an ocular sample can detect microbial genome comprehensively, and viral pathogens, which were not detected by conventional examination.

Purpose: To determine a correlation between temperature and blood flow in the ocular anterior segment, and their effects on corneal temperature. Methods: In experiment 1, we recruited 40 eyes and measured the temperature and blood flow in the ocular anterior-segment (upper/lower eyelid skin, palpebral and bulbar conjunctiva, and cornea) before and after application of warm compresses. In experiment 2, we recruited 20 eyes and measured the same tissues before and during stimulation using water and capsaicin solution in the oral cavity. Results: In experiment 1, the temperatures of the upper/lower eyelid skin and cornea increased significantly until 15 min after the application of the warm compress; the temperatures of the palpebral and bulbar conjunctiva increased significantly until 10 min. The blood flow in the upper/lower eyelid skin and bulbar conjunctiva increased significantly until 10 min, and that of the palpebral conjunctiva increased significantly until 15 min. In experiment 2, the temperatures were correlated significantly with the blood flow in the upper and lower eyelid skin and palpebral and bulbar conjunctiva. The temperature of all locations and palpebral conjunctival blood flow contributed independently to the corneal temperature. Conclusions: In the ocular anterior segment, the temperature and blood flow were correlated significantly, and contributed to the corneal temperature.