Masahide Yanagi

Vascular risk factors in glaucoma: a review

Glaucoma, one of the major causes of blindness in the world, is a progressive optic neuropathy. Elevated intraocular pressure is a well‐known major risk factor for glaucoma. In addition, there is growing evidence that vascular factors may play a role in glaucoma pathogenesis. Systemic (e.g. hypertension, diabetes) and ocular vascular factors (e.g. ocular blood flow, ocular perfusion pressure) have been assessed for associations with glaucoma. However, direct and convincing evidence for primary mechanisms of glaucoma is still lacking. The aim of this review is to summarize the evidence implicating vascular factors in the pathogenesis of glaucoma, with particular emphasis on the role of ocular blood flow and ocular circulation as risk factors for primary open angle glaucoma.

Is the association between smoking and the retinal venular diameter reversible following smoking cessation

PURPOSE Wider retinal venular caliber is shown to be associated with an increased risk of stroke, and smoking is associated with a wider retinal venular caliber. However, the impact of smoking cessation on the retinal vessels has not been previously reported. We examined this issue in an adult cohort of atomic bomb survivors. METHODS In the Adult Health Study of Japanese atomic bomb survivors, 1664 subjects had retinal photographs taken from 2006 to 2008. The central retinal artery and vein equivalents (CRAE and CRVE) were calculated using a semiautomated software program. Multiple surveys have assessed the effects of smoking since 1963. The associations between smoking, the time since cessation, and the retinal vessel caliber were determined using linear mixed effects models. RESULTS The CRVE was associated with an increased number of cigarettes smoked per day among women after adjusting for potential confounding factors (age, sex, blood pressure, hypertensive medications, white blood cell count, diabetes, body mass index, lipids, and radiation dose). Females who smoked 10 cigarettes per day had a 6.9-μm wider mean CRVE (P = 0.001) than nonsmokers. Females who had stopped smoking for 10 or more years had a mean CRVE similar to those who had never smoked (191.8 vs. 194.4 μm; P = 0.23). These associations were not observed in males or for CRAE. CONCLUSIONS Wider retinal venular caliber is associated with smoking in Japanese females; however, this association becomes nonsignificant after 10 or more years of smoking cessation, suggesting that the impact of smoking on retinal venular dilation is reversible following long-term smoking cessation.

Association between glaucoma eye drops and hyperemia.

PurposeWe used an image analysis software program to quantitatively investigate conjunctival injection in patients treated with eye drops for glaucoma.MethodsWe compared 169 patients (89 men and 80 women) with a diagnosis of glaucoma. Photographs of the conjunctiva were taken on the temporal side of each patient’s right eye using a slit lamp. We determined the mean pixel frequencies of the conjunctival blood vessels from the photographs.ResultsThe ocular hyperemia of the patients being treated with prostaglandins was more severe than that of the patients being treated with beta-blockers or no eye drops. In multiple comparisons of each of the eye drops, the control group had a significantly lower degree of hyperemia than did the patients being treated with each of the various prostaglandin analogs (latanoprost, travoprost, tafluprost, and bimatoprost). Among the patients receiving prostaglandin, the percentage of those with hyperemia was highest in the bimatoprost users, followed in order by the travoprost, latanoprost, and tafluprost users. However, no significant differences were found among the different prostaglandin analogs in terms of the percentage of patients with hyperemia.ConclusionOur software program may be useful for evaluating the hyperemic effects of eye drops used for glaucoma. The particular type of prostaglandin analog seems to determine the level of conjunctival hyperemia during ocular hypotensive medical treatment.

Exposure to Atomic Bomb Radiation and Age-Related Macular Degeneration in Later Life: The Hiroshima-Nagasaki Atomic Bomb Survivor Study.

PURPOSE To investigate the association between radiation exposure from the atomic bombings and the prevalence of age-related macular degeneration (AMD) among older residents of Hiroshima and Nagasaki. METHODS The Adult Health Study is a cohort study of atomic bomb survivors living in Hiroshima and Nagasaki, comprising 2153 participants who underwent examinations with retinal fundus photographs in 2006-2008. The radiation dose to the eye for the analysis was estimated with the revised dosimetry system (DS02). The retinal photographs were graded according to the Wisconsin Age-Related Maculopathy Grading System modified for nonstereoscopic retinal images. Early and late AMD were defined according to the type of lesion detected in the worse eye of the participants. Person-specific data were analyzed by using a logistic regression model to assess the association between radiation dose and AMD. RESULTS Among the 1824 subjects with gradable retinal images (84.7% of the overall participants), the estimated eye dose was widely distributed, with a mean of 0.45 Gy and standard deviation of 0.74 Gy. The prevalence of early and late AMD was 10.5% and 0.3%, respectively. There were no significant associations between radiation dose and AMD, with each 1-Gy increase in exposure, adjusted odds ratio was 0.93 (95% confidence interval [CI], 0.75-1.15) for early AMD and 0.79 (95% CI, 0.21-2.94) for late AMD. CONCLUSIONS No significant associations were found between atomic bomb irradiation early in life and the prevalence of early or late AMD later in life among Japanese atomic bomb survivors.

Development of automated conjunctival hyperemia analysis software.

Abstract: Conjunctival hyperemia is observed in a variety of ocular inflammatory conditions. The evaluation of hyperemia is indispensable for the treatment of patients with ocular inflammation. However, the major methods currently available for evaluation are based on nonquantitative and subjective methods. Therefore, we developed novel software to evaluate bulbar hyperemia quantitatively and objectively. First, we investigated whether the histamine-induced hyperemia of guinea pigs could be quantified by image analysis. Bulbar conjunctival images were taken by means of a digital camera, followed by the binarization of the images and the selection of regions of interest (ROIs) for evaluation. The ROIs were evaluated by counting the number of absolute pixel values. Pixel values peaked significantly 1 minute after histamine challenge was performed and were still increased after 5 minutes. Second, we applied the same method to antigen (ovalbumin)-induced hyperemia of sensitized guinea pigs, acquiring similar results except for the substantial upregulation in the first 5 minutes after challenge. Finally, we analyzed human bulbar hyperemia using the new software we developed especially for human usage. The new software allows the automatic calculation of pixel values once the ROIs have been selected. In our clinical trials, the percentage of blood vessel coverage of ROIs was significantly higher in the images of hyperemia caused by allergic conjunctival diseases and hyperemia induced by Bimatoprost, compared with those of healthy volunteers. We propose that this newly developed automated hyperemia analysis software will be an objective clinical tool for the evaluation of ocular hyperemia.

Efficacy of amniotic membrane-assisted bleb revision for elevated intraocular pressure after filtering surgery.

Purpose: To compare the effectiveness of standard revision surgery using mitomycin C (MMC) with revision using amniotic membrane transplantation and MMC for elevated intraocular pressure (IOP) after trabeculectomy. Patients and methods: A retrospective, nonrandomized comparative study of 36 eyes of 36 patients with a failed trabeculectomy. Patients were divided into two groups, ie, a nonamnion-transplanted group and an amnion-transplanted group. The amniotic membrane was placed on the scleral flap under the conjunctiva in the amnion-transplanted group. Both groups recovered filtration of aqueous humor from the surgical site with the adjunctive use of MMC. The changes in IOP and cumulative survival rate were compared for the two groups. Success was defined as a 30% reduction in IOP from the preoperative IOP and maintenance below 21 mmHg with or without the use of antiglaucomatous agents. Results: The mean preoperative IOP was not significantly different in the two groups. The mean postoperative IOP in the nonamnion group, 12.1 ± 5.5 mmHg, was significantly lower than the IOP in the amnion group, 16.0 ± 3.7 mmHg. Survival curves in the two groups did not reach significantly different levels. Conclusions: Conventional surgical bleb revision with MMC can significantly reduce the elevated IOP associated with a failed filtration bleb. The use of an amniotic membrane transplant did not improve the surgical outcome in our cases.