Hiroyasu Taniguchi

Cataract in atomic bomb survivors.

Purpose: Ophthalmologic examinations were conducted on atomic bomb (A‐bomb) survivors 55 years after exposure. Materials and methods: A‐bomb survivors who had been exposed before 13 years of age at the time of the bombings in 1945 or who had been examined in a previous study between 1978 and 1980. The examinations, conducted between June 2000 and September 2002, included slit‐lamp examination, digital photography and a cataract grading system for three parts of the lens (nucleus, cortex and posterior subcapsule) as an outcome variable. Proportional odds logistic regression analysis was conducted using the lowest grading class as a reference and included explanatory variables such as age, sex, city, dose and various cataract‐related risk factors. When the grades in an individual differed, the worst grade was used. Results: Results indicate that odds ratios (ORs) at 1 Sv were 1.07 (95% confidence intervals [CI] 0.90, 1.27) in nuclear colour, 1.12 (95% CI 0.94, 1.30) in nuclear cataract, 1.29 (95% CI 1.12, 1.49) in cortical cataract and 1.41 (95% CI 1.21, 1.64) in posterior subcapsular cataract. The same was true after excluding 13 people whose posterior subcapsular cataracts had been previously detected. Conclusion: Significant radiation effects were observed in two types of cataracts in A‐bomb survivors.

Anticoagulation Therapy and Ocular Surgery

BACKGROUND AND OBJECTIVEnIt is not rare for patients receiving anticoagulant therapy to undergo ocular surgery; however, there are no clear guidelines with reference to the operative management of the eye. This study examines the complications in patients receiving anticoagulant therapy who undergo ocular operations and suggests a management regimen for these patients.nnnPATIENTS AND METHODSnThe authors retrospectively analyzed 52 patients receiving anticoagulant therapy who underwent ocular surgery between 1993 and 1995. Data included sex, age, reason for anticoagulant therapy, operative procedure, complication rate, and length of time anticoagulant therapy was stopped or reduced prior to surgery. To show the base-line complication rate at their institution, data of patients not receiving anticoagulation therapy were added.nnnRESULTSnTiclopidine hydrochloride, an antiplatelet drug, was administered to 24 patients. Warfarin sodium was administered to 8 patients, heparin was administered to 8 patients, and other anticoagulants were administered to 20 patients. There were no significant differences in complications between the groups that stopped or reduced anticoagulant therapy and those that did not, but speech disturbance due to thrombotic complication occurred in 1 of 10 patients in whom ticlopidine hydrochloride was stopped or reduced. Hemorrhagic complications occurred in 50% of those who continued ticlopidine hydrochloride, but in none of those who discontinued it (P = .019). There was a significant difference in hemorrhagic complications after cataract surgery between the phacoemulsification, aspiration, and intraocular lens implantation (PEA + IOL) and the planned extracapsular cataract extraction and intraocular lens implantation (PECCE + IOL) groups that continued the drug (P = .0011). No patients showed visual acuity reduction due to hemorrhagic complications.nnnCONCLUSIONSnTo avoid life-threatening systemic complications, one need not always stop anticoagulant therapy before performing only cataract surgery. Cataract surgery in patients receiving ticlopidine hydrochloride should be performed with PEA + IOL via a small sclerocorneal or a corneal incision. In cataract surgery for patients receiving anticoagulant therapy, hemorrhagic complications are more frequent than in patients not receiving anticoagulant therapy.

Apoptosis of the hyaloid artery in the rat eye

The hyaloid artery is a vestigial vessel situated on the optic nerve extending to the posterior surface of the lens in the vitreous cavity of the eye. We studied the nature and pattern of cell death during regression of the hyaloid artery. The cells comprising the hyaloid artery appear to be alive for 20 days after birth in the rat, and cell death during regression of the hyaloid artery has the characteristics of apoptosis. We observed apoptotic bodies containing condensed chromatin and identified the hyaloid vessels as targets of macrophage-mediated remodelling. Using the TUNEL method for labeling fragmented DNA in vascular cells, we assessed the pattern of apoptotic cell death during hyaloid artery regression. Our study demonstrated the appearance of apoptosis in pericytes as well as endothelial cells during regression in the vasculature. In pericytes, apoptosis appeared to begin or to occur more frequently than in endothelial cells. Both morphological and TUNEL analyses indicated that capillary apoptosis occurs mainly from day 10 to day 20 after birth rather than from the 1st day. Macrophages were present near the hyaloid artery and these may influence apoptosis.

Long-term effect on optic nerve of silicone oil tamponade in rabbits: histological and EDXA findings

Purposeu2003Side-effects after intravitreal use of silicone oil (SO) are not well defined and elucidated. The object of this study was to examine the influence and toxicity of SO on the optic nerve after vitrectomy with SO tamponade.Methodsu2003We injected medical grade SO and emulsified SO into rabbit eyes after gas-mediated vitreous compression and examined the eyes by light microscopy (LM), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDXA) (point analysis and area analysis) 6 months after injection. We compared the findings in the non-treated eyes and eyes with only gas-mediated vitreous compression with those in SO-injected eyes.Resultsu2003Vacuole-like structures were seen in the optic nerve posterior to the lamina cribrosa. In the group treated with only gas-mediated vitreous compression, the myelin structures were shown by TEM to be destroyed and replaced by glial tissue, while in groups injected with medical grade or emulsified SO severe destruction of the myelin sheath (myelinolysis) was observed. Silicone was identified at the electron-dense edges of the vacuoles by EDXA point analysis, but not in the vacuoles without electron-dense deposits. Dots of Si K alpha were not seen in the control groups, and dense dots were observed in SO-injected groups, by EDXA area analysis.Conclusionsu2003Some of the vacuoles might be artefacts caused by insufficient fixation or the operative procedure, but TEM showed almost no artefacts in the control optic nerve. Thus, most vacuoles may be SO storage sites. SO uptake into the optic nerve might play a role in the pathogenesis of optic nerve atrophy after SO injection.

Hyperbaric oxygen therapy reduces visual field defect after macular hole surgery

BACKGROUND AND OBJECTIVEnOne of the serious complications that may arise after macular hole (MH) surgery is a temporal visual fields (TVF) defect. We hypothesized that hyperbaric oxygen (HBO) therapy improves the visual field (VF) in these patients.nnnMATERIALS AND METHODSnVitrectomy for MH was performed on 73 eyes from 1994 to 1997. TVF defect was detected in 19 eyes and, of that 19, 12 patients were followed. Seven patients were treated with HBO therapy and 5 were controls. HBO was performed for approximately 110 minutes a day with 100% oxygen inhalation and a maximum of 2.8 atmospheric pressure. This continued for 20 days. The preoperative VF determined by kinetic perimetry was considered to be 100%, and the VF following HBO therapy was compared with that standard.nnnRESULTSnWe detected VF defect (postoperative VF area average 71.9+/-12.8% of the preoperative VF). In all 5 patients who had no HBO therapy, TVF defects remained, while the TVF recovered remarkably in all patients treated with HBO therapy. The VF recovered to 81.7+/-16.7% of the preoperative VF after 3 days of HBO, and to 91.6+/-15.8% months after HBO therapy.nnnCONCLUSIONnWe speculated that the cause of TVF defect is likely to be chorioretinal circulation disturbance during surgery, and that HBO activates the retinal cells and improves VF. We conclude that HBO is useful in the treatment of TVF defect after macular hole surgery.

Inhibition of experimental choroidal neovascularization by an anti-growth agent inhibiting vascular endothelial development

PURPOSEnTo determine whether FR118487, a recently developed angiogenesis inhibitor, affects experimental choroidal neovascularization (CNV) induced by laser photocoagulation in pigmented rats.nnnMETHODSnFocal laser photocoagulation (argon green 50 mW, 0.04 seconds, 200 microm) was applied to the retinochoroid of normal Brown Norway rats. Systemic administration of FR118487 (1.0 mg/kg body weight per day) with a mini-osmotic pump implanted in the subcutaneous tissue of the neck was started just after laser photocoagulation and continued for 2 weeks. Choroidal vascular casts were made 2 weeks after laser photocoagulation and were examined with a scanning electron microscope. CNV formation was divided into three grades and evaluated.nnnRESULTSnLaser-induced CNV formation was significantly less in rats given FR118487 than in control rats. CNVs in rats treated with FR118487 were less well developed than in the controls.nnnCONCLUSIONnFR118487 inhibits the development of experimental CNV induced by photocoagulation in pigmented rats.