Iron-generated hydroxyl radicals kill retinal cells in vivo: effect of ferulic acid.

Siderosis bulbi is vision threatening. An investigation into its mechanisms and management is crucial. Experimental siderosis was established by intravitreous administration of an iron particle (chronic) or FeSO(4) (acute). After siderosis, there was a significant dose-responsive reduction in eletroretinogram (a/b-wave) amplitude, and an increase in OH level, greater when caused by 24 mM FeSO(4) than that by 8 mM FeSO(4). Furthermore, the FeSO(4)-induced oxidative stress was significantly blunted by 100 microM ferulic acid (FA). Siderosis also resulted in an excessive glutamate release, increased [Ca(++)](i), and enhanced superoxide dismutase immunoreactivity. The latter finding was consistent with the Western blot result. Obvious disorganization including loss of photoreceptor outer segments and cholinergic amacrines together with a wide-spreading ferric distribution across the retina was present, which were related to the eletro-retinographic and pathologic dysfunctions. Furthermore, b-wave reduction and amacrine damage were respectively, significantly, dose-dependently, and clearly ameliorated by FA. Thus, siderosis stimulates oxidative stress, and possibly, subsequent excitotoxicity, and calcium influx, which explains why the retina is impaired electro-physiologically and pathologically. Importantly, FA protects iron toxicity perhaps by acting as a free radical scavenger. This provides an approach to the study and treatment of the iron-related disorders such as retained intraocular iron and Alzheimer disease.

Pulsatile ocular blood flow in asymmetric exudative age related macular degeneration.

BACKGROUND/AIMS: Decreased perfusion or increased vascular resistance of the choroidal vessels had been proposed as the vascular pathogenesis for age related macular degeneration (AMD). This study planned to answer the question whether pulsatile ocular blood flow (POBF) was different in patients with asymmetric exudative AMD between eyes with drusen, choroidal neovascularisation (CNV), or disciform scar. METHODS: 37 patients with asymmetric exudative AMD were enrolled in this observational case series study. POBF were measured in both eyes of each subject. Eyes with high myopia, anisometropia, recent laser treatment, and glaucoma were excluded. RESULTS: After adjusting for ocular perfusion pressure, intraocular pressure, and pulse rate, multivariate regression analysis with generalised estimating equation showed POBF was significantly higher in eyes with CNV (1217 (SD 476) microl/min) than the contralateral eyes with drusen (1028 (385) microl/min) (p = 0.024). Eyes with disciform scar had lower POBF than the contralateral eyes with drusen (999 (262) microl/min and 1278 (341) microl/min, respectively, p<0.001). There was no significant correlation between the POBF and the lesion size of the CNV. CONCLUSION: The POBF in eyes with drusen was lower than their fellow eyes with CNV, but higher than their fellow eyes with disciform scar. This finding suggests that haemodynamic differences between fellow eyes in individuals are relevant to the development of CNV and the formation of disciform scar. Further studies on the follow up patients might shed light on the pathogenesis of exudative AMD.

Visual impairment in a Taiwanese population: prevalence, causes, and socioeconomic factors.

PURPOSE: We sought to estimate the prevalence of visual impairment among an elderly population in urban Taiwan, determine the causes of visual impairment, and gain information about certain socioeconomic factors associated with visual impairment. METHODS: A population-based survey of ocular diseases in residents aged 50 years or older was conducted in Peitou Precinct, Taipei, Taiwan. All participants underwent a comprehensive ophthalmic examination, including visual acuity measurement, using standardized protocols. Demographic data, marital status, employment status, and educational level were gathered through an interview. RESULTS: A total of 2034 participants completed the visual acuity measurements. The prevalence of visual impairment (defined as best-corrected visual acuity in the better eye <6/18) among this population was 2.75% (95% confidence intervals: 2.04%-3.46%). Three major causes of visual impairment were cataract (30.4%), high myopic macular degeneration (25.0%), and age-related macular degeneration (14.3%). In multivariate analysis, age was positively correlated with visual impairment (P < 0.001), and higher education level was associated with a significant decrease in the odds of being visually impaired (P < 0.001). No relation was found between visual impairment and sex, or marital and employment status. CONCLUSIONS This study provides the first information about the prevalence and causes of visual impairment in Taiwan, and identifies age and educational level as the most important factors related to visual impairment. Additional educational programs should be developed to improve individual awareness of age-related ocular diseases and the availability of current ophthalmic intervention.

Effect of continuous versus multiple intermittent light exposures on rat retina.

The damaging effects of continuous light exposure to the albino rat retina have been well documented. However, the cumulative effects of multiple light exposures are not well defined. We therefore compared the retinal injury induced by a single 24 hour light exposure with that caused by three intermittent exposures of 8 hours each. Eight dark-adapted albino Lewis rats were exposed for 24 hours to green fluorescent light (490-580 nm) at an illuminance level of 175 foot-candles. A second group of 8 rats was exposed under similar conditions in three split doses of 8 hours each at intervals of 7 days between each exposure. Recovery was allowed in total darkness, and the animals were sacrificed 2 weeks following the last exposure. Retinal damage was assessed by morphometry and light and electron microscopy. Mild cumulative retinal injury, mostly in photoreceptor cells with relative sparing of the retinal pigment epithelium, was seen in the split dose group, while extensive damage involving photoreceptor cells and retinal pigment epithelium was noted in the group exposed continuously for 24 hours.

Clip appendectomy.

The clip appendectomy is an alternative to the classical suture appendectomy. The use of a new polymer clip facilitates this technique. During pelvic reconstructive surgery an appendectomy may be indicated when suspected appendiceal pathology (such as endometriosis) could adversely affect the surgical outcome. Clip appendectomy can reduce the operative time without increasing morbidity.

Long-term visual outcomes of laser-treated threshold retinopathy of prematurity: a study of refractive status at 7 years.

PURPOSE: To assess the long-term visual outcomes and refractive status in patients with diode laser-treated threshold retinopathy of prematurity (ROP), and to investigate the causes of impaired visual function. METHOD: A total of 60 eyes of 30 consecutive patients with diode laser-treated threshold ROP were recalled for assessment at the age of 7 years or more. RESULTS: There were 38 eyes (65.5%) achieving 6/12 or better vision, however, an unfavourable visual outcome (6/60 or worse) occurred in four eyes (6.9%). One eye (1.7%) had unfavourable structural outcome. Of these 60 laser-treated eyes, 46 eyes (77.0%) were myopic, the overall mean spherical equivalent was -3.87 D. Anisometropia (>or=1.5 D) was also noted in 14 patients (46.7%). Strabismus was present in nine patients (30.0%). Perinatal neurological events of intraventricular haemorrhage (IVH) were identified in eight children (26.7%), periventricular leucomalacia (PVL) in eight children (26.7%), and cerebral palsy (CP) in four children (13.3%). There was a statistically significant association of the presence of strabismus with PVL (P=0.002). The presence of anisometropia was a significant risk factor associated with poor visual outcome of 6/15 or worse in laser-treated ROP (P=0.002). CONCLUSION: The majority of patients with diode laser-treated threshold ROP had favourable anatomical and visual outcomes. However, anisometropia, advanced refractive error, strabismus, and perinatal neurological events remain important causes of impaired visual function. Long-term follow-up is very important for early detection and timely treatment of these ocular morbidities.

Synonymy of Candida methylica with Candida boidinii and of Candida methanolophaga with Candida succiphila.

Some Candida species which can use methanol as a sole carbon source were studied by performing chemotaxonomic tests; we determined the ubiquinone systems of these organisms, their DNA base compositions, their electrophoretic karyotypes, and their DNA relatedness values. The type strains of Candida methanolophaga and Candida succiphila had similar DNA base compositions and exhibited 90% DNA relatedness. All Candida boidinii and Candida methylica strains had DNA G + C contents of 30.8 to 31.0 mol%, and these organisms exhibited 87 to 101% DNA relatedness to the type strain of C. boidinii. We propose that C. methanolophaga and C. methylica should be synonyms of C. succiphila and C. boidinii, respectively.

DNA hybridization and electrokaryotype study of some Candida species.

Some Candida species which were similar to each other in phenotypic characteristics were studied by chemotaxonomic and molecular taxonomic comparison including the ubiquinone systems, electrophoretic karyotypes, DNA base composition and DNA relatedness. Candida viswanathii and Candida lodderae showed similar electrophoretic karyotypes and DNA base composition and demonstrated 89 to 91% DNA relatedness, confirming their synonymy.

Natural course of submacular hemorrhage.

BACKGROUND: Age-related macular degeneration (ARMD) is the most prevalent cause of blindness in the elderly population. This study retrospectively evaluated the natural course of submacular hemorrhage related to ARMD. METHODS: We reviewed the records of patients with submacular hemorrhage and foveal avascular zone involvement at the Veterans General Hospital-Taipei from 1981 to 1996. Data were collected from color fundus pictures, fluorescence angiographic films and visual acuity changes. RESULTS: Data from a total of 86 eyes with age-related macular degeneration (ARMD) and 37 non-ARMD eyes were collected. Analysis of data from the ARMD group revealed 10.5% visual acuity improvement six months after presentation and a final mean acuity of 0.069. Analysis of data from the non-ARMD group revealed 29.7% visual acuity improvement and a final mean acuity of 0.388. CONCLUSIONS: In this study, patients with submacular hemorrhage had spontaneous visual improvement even without surgery, especially those without subretinal neovascularization.

Molecular and chemical taxonomic differentiation of Candida boidinii Ramirez strains.

Molecular and chemical taxonomic characteristics, including DNA base composition, electrophoretic karyotype, restriction fragment length polymorphism of genes coding for rRNA, cellular fatty acid composition, and ubiquinone systems, were studied for 19 strains of Candida boidinii Ramirez. Electrophoretic karyotype and restriction fragment length polymorphism demonstrated marked differences among these strains. A combination of molecular and chemical analyses can serve as a reliable tool for culture authentication and quality control of industrial strains.

Role of heredity in the genesis of myopia.

Previous studies suggest that myopia in parents may influence the genesis of myopia in their offspring. In this study, we surveyed 2888 children of Chinese descent in China and Hong Kong to determine the relationship between the refractive state of parents and their children. The age range of the children was 7-17 years. Refraction was measured using a Canon R-22 objective infrared autorefractor and a survey on family history of ametropia was conducted using a questionnaire. We found that children with myopic parents are more likely to be myopic.

Histopathologic study of autosomal dominant vitreoretinochoroidopathy. Peripheral annular pigmentary dystrophy of the retina.

Autosomal dominant vitreoretinochoroidopathy (ADVIRC), a recently described disease, is clinically characterized by a slowly progressive or stationary circumferential peripheral pigmentary retinopathy with fibrillar condensation of the vitreous. Histopathologic study of an 88-year-old patient with this disease showed disorganization of the peripheral retina with focally atrophic retinal pigment epithelium (RPE). Altered pigment epithelial cells surrounded retinal blood vessels and lined the internal limiting membrane. At the equator, a remarkable and possibly unique multifocal loss of photoreceptor cells was seen. An extensive preretinal membrane, consisting of condensed vitreous with cellular debris and layers of Müller cells, was demonstrated by electron microscopic examination and immunohistochemistry. Histologically, this entity has some similarities to and some differences from retinitis pigmentosa. The clinical features are distinctive.

Population-based study on prevalence and risk factors of age-related cataracts in Peitou, Taiwan.

BACKGROUND: Age-related cataracts are the main cause of blindness throughout the world. Nonetheless, population-based data on the epidemiology of age-related cataracts among Taiwanese populations are not readily available. This study was conducted to estimate the prevalence of age-related cataracts and to determine the relationships of age, gender, blood pressure, diabetes and smoking to the risks of age-related cataracts in an urban Taiwanese population. METHODS: The study was part of a population-based survey of eye diseases among residents aged 50 years or older in Peitou Precinct, Taipei, Taiwan. Of the 2,700 eligible persons, 2,038 (75.5%) underwent a standard evaluation protocol including dilated slit-lamp examination, a questionnaire of medical and ophthalmic histories and blood pressure measurement. RESULTS: Among the participants, 1,040 were diagnosed with age-related cataracts. The prevalence was 51.0% (95% confidence interval, 48.9%-53.2%). Nuclear opacity was the most prevalent type (718/1,040; 35.2%) of cataracts, followed by posterior subcapsular opacity (311/1,040; 15.3%) and cortical opacity (163/1,040; 7.8%). An increased risk of age-related cataracts was associated with female gender (p = 0.002). When a single type of lens opacity was considered, diabetes was significantly associated with a posterior subcapsular cataract (p = 0.022). Overall, older women with diabetes and relatively lower diastolic blood pressure were more likely to have age-related cataracts. CONCLUSIONS: The study provided the first prevalence data on age-related cataracts in an urban Taiwanese population and highlighted the relationships of age, gender, blood pressure and diabetes to the frequency and type of age-related cataracts. The results can assist in the design and implementation of intervention programs to reduce the prevalence of age-related cataracts.

Indocyanine green angiography of central serous chorioretinopathy.

BACKGROUND: Fluorescein angiography has not been particularly useful in studying the choroidal vasculature because of limited fluorescence transmission through the retinal pigment epithelium (RPE). Indocyanine green (ICG), a dye that absorbs and fluoresces in the near-infrared range and does not leak extensively through the choriocapillaries, because of its highly protein-bound nature, allows improved imaging of the choroid compared with fluorescein angiography. This study was performed to evaluate changes in the choroidal circulation in the eyes of patients with central serous chorioretinopathy (CSCR) using ICG angiography. METHODS: We prospectively performed ICG angiography and fluorescein angiography in 41 eyes with classic or chronic CSCR (diffuse retinal pigment epitheliopathy) to investigate the choroidal abnormalities. RESULTS: The ICG angiographic studies revealed choroidal staining in all eyes of the two forms of CSCR. Classic CSCR (35 eyes), when compared with the chronic form (6 eyes), were associated with more RPE leakage (89% vs 33%; p = 0.008), more prominent ischemic lobules (69% vs 0; p = 0.003), and less late phase hypofluorescent spots (46% vs 100%; p = 0.02). CONCLUSIONS: Choroidal hyperpermeability may be a causative factor of acute or chronic CSCR and may help in the diagnosis of atypical cases of CSCR. The differences in the results between these two types of CSCR using ICG angiography, allowed for a better understanding of the choroidal hemodynamic change than fluorescein angiography.

Pseudophakic Penicillium endophthalmitis.

A healthy 76-year-old woman complained of redness and a painful sensation in her right eye after cataract surgery 5 months previously. The eye was treated with topical corticosteroid and ciprofloxacin, and a soft exudative mass on the nasal lower iris was noted later. Fungal endophthalmitis was suspected and a repeat aqueous culture grew Penicillium spp. After treatment with topical natamycin and an intracameral injection of amphotericin B, the endophthalmitis was cured. We describe the disease course and management and discuss topical corticosteroids as a possible risk factor for increasing the dissemination of Penicillium infection. This was a unique case of successful therapy resulting in the cure of Penicillium endophthalmitis in an immunocompetent patient.

Digital indocyanine green angiography in chorioretinal diseases.

BACKGROUND: Fluorescein angiography (FA) is important in the diagnosis of chorioretinal diseases; however, it has some limitations. We conducted this study to evaluate whether digital indocyanine green (ICG) angiography can offer enhanced image in chorioretinal diseases. METHODS: Digital indocyanine green angiography with scanning laser ophthalmoscope (SLO) was performed in 314 patients with various chorioretinal diseases. This coupled digital imaging system can offer instant images, process and store data by computer, and give convenient hardcopy generation. RESULTS: The digital ICG angiography provided enhanced image resolution of the choroid compared with FA. The disease categories included choroidal neovascularization (CNV), choroidal tumor, inflammatory choroidal disease, ischemic choroidal disorder, idiopathic central serous chorioretinopathy and retinal macroaneurysm. CONCLUSIONS: ICG angiography is a useful adjunctive diagnostic technique to fluorescein angiography for various chorioretinal diseases. It is especially useful in the diagnosis of occult and recurrent CNV, as well as choroidal tumor and choroiditis. With greater clinical experience, ICG angiography is promising in giving additional clinical information for many other chorioretinal diseases.

Pulsatile ocular blood flow of choroidal neovascularization in asymmetric age-related macular degeneration after transpupillary thermotherapy.

PURPOSE: A previous study has shown that the pulsatile ocular blood flow (POBF) in eyes with asymmetric age-related macular degeneration (AMD) differs. Whereas eyes with drusen have higher POBF than contralateral eyes with disciform scarring, the POBF of eyes with drusen is lower relative to contralateral eyes with choroidal neovascularization (CNV). This study was designed to assess whether the POBF of eyes with CNV changes after transpupillary thermotherapy (TTT), using the contralateral eyes with drusen or scarring without TTT as controls. METHODS: In total, 26 patients with CNV in one eye and drusen or scarring in the other were enrolled in this prospective case series. Eyes with CNV were treated with TTT. POBF was measured monthly in both eyes of each subject. RESULTS: Before TTT, the POBF of eyes with CNV was 1179+/-317 microl/min. After TTT, the POBF of CNV eyes had decreased at 1 month (1015+/-273 microl/min, P=0.002) and 2 months (945+/-398 microl/min, P=0.011) of follow-up, but had rebounded at 3 months (P=0.441) and 6 months (P=0.084). CONCLUSIONS: These findings suggest that TTT decreases the pulsatile choroidal blood flow in eyes with CNV in patients with asymmetric AMD and the effects persist for 2 months. POBF may be used as a modality to monitor the therapeutic effects of CNV in asymmetric exudative AMD.