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At least 19 recordsLinked to original sources
PubMed1987

Myeloid bodies associated with lipid droplets in pinealocytes of blind, blind-bulbectomized, blind-underfed or blind cold-exposed rats.

The ultrastructure of pinealocytes was studied in rats subjected to manipulations known as enhancers of pineal actions: blindness (B), blindness + olfactory bulbectomy (BObx), blindness + underfeeding (BU), blindness + cold exposure (BC). A large number of myeloid bodies (MBs) were found especially in the light pinealocytes of BObx, BU and BC rats but not in intact controls. These MBs were, in most cases, associated with lipid droplets. The presence of a large number of MBs in rats in which pineal-dependent gonadal impairment has been demonstrated, strongly supports the hypothesis that MBs play a role in pineal photoneuroendocrine activity.

Animals↗
PubMed2000

Integrity and research: introducing the concept of dual blindness. how blind are double-blind clinical trials in alternative medicine?

Double-blind methodology is used in clinical studies to control for potential external or nonspecific influences such as belief and expectation, as well as to maintain as much objectivity as possible on the part of the researchers. Despite not being feasible in all medical disciplines, as in the case of some modalities of complementary and alternative medicine, there are numerous studies that spuriously claim its use. Distinctions and standards therefore need to be set to avoid misleading information. We propose a new term in research methodology, dual-blind, to describe a methodological alternative in which the caregiver is not blind but the patient and an external evaluator/investigator are. The term double-blind should be used strictly to describe a methodology in which both the patient and the caregiver are blind. Making the distinction between these two terms will result in more reliable reports of clinical trials and will support integrity in research.

Bias↗
PubMed1993

Causes of blindness in children attending four schools for the blind in Thailand and the Philippines. A comparison between urban and rural blind school populations.

Using WHO definitions of visual loss and a standardised methodology, 256 children were examined in schools for the blind in Thailand (1 school) and the Philippines (3 schools). 244 (95%) were blind (BL) or severely visually impaired (SVI). Causes of SVI and blindness were classified anatomically and aetiologically, and avoidable causes identified. Causes of visual loss in Khon Kaen, Thailand (n = 65) and Manila, Philippines, (n = 113) were similar, with conditions of the whole globe accounting for 27.7 and 27.4% of SVI/BL; retinal disease 29.2 and 23.0%; cataract 16.9 and 16.8%; corneal disease 12.3 and 13.4%; and optic nerve disease and glaucoma 6.2 and 8.8%. Perinatal factors accounted for 20.0 and 23.0% of SVI/BL; hereditary disease 13.8 and 17.7%; and 12.3 and 15.0% was due to events occurring during childhood. The underlying aetiology could not be determined in 50.8 and 41.6% of cases, respectively. In the two schools together twenty six children (15%) were blind from retinopathy of prematurity (ROP) and 16 (9%) from corneal scarring attributed to Vitamin A deficiency. 103 of 178 (58%) children had avoidable causes of visual loss. In the Filipino towns of Baguio and Davao (n = 66), the causes of visual loss were different from those in Khon Kaen and Manila, with 54.8 and 42.9% of SVI/BL being due to corneal disease, and only 3.2 and 8.5% to retinal disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2001

[The blindness in the literature-Jose Saramago: blindness and Albert Bang: the blind witness].

Two novels with different aspects of blindness seen through the doctors eyes. The Portuguese Nobel-prize winner José Saramago's story of a city struck by an epidemic of "white blindness", where the truth is what we cannot bear to see. The Danish author and unskilled labourer Albert Bang's (synonym with Karl E. Rasmussen) crime novel describes a blind or pretend to be blind butcher, who is a witness to a murder. Both novels are lyric, thought-provoking and insightful.

Blindness↗
PubMed1989

Histopathologic features of DMBA-induced mammary tumors in blind-underfed, blind-anosmic, and blind cold-exposed rats: influence of the pineal gland.

The influence of the pineal gland on the histopathologic changes induced in mammary glands by 7, 12-dimethylbenz(a)-anthracene (DMBA) has been studied. To achieve the maximum expression of pineal action in animals, 28-day-old female Sprague-Dawley rats were subjected to one of the following treatments: blindness + olfactory bulbectomy (BA), blindness + underfeeding (BU), or blindness + cold exposure (BC). Half of the rats in each group were also pinealectomized. Animals that were intact or only pinealectomized served as controls. Each animal received a single intragastrical dose of DMBA (20 mg) 4 weeks after performing the treatments mentioned above. At 28 weeks of age animals were sacrificed, and mammary tumors as well as mammary glands without macroscopic lesions were collected. Animals of the BU group failed to develop any tumors throughout the 20-week control period. In the remaining groups, tumors were found; the relation between number of adenocarcinomas (AC) and fibroadenomas was similar, always with a greater incidence of ACs. Some ACs showed areas with changes in the ductal epithelium that are considered signs of tumoral regression; pinealectomized animals had the lowest incidence of ACs with signs of regression. Ductule hyperplasia, considered as a premalignant lesion, was more frequent in pinealectomized rats than in controls and in animals with enhanced pineal function (BA, BU, and BC). Some nontumoral mammary glands showed dysplastic lesions; these lesions were less frequent in BU rats than in controls. We conclude that suppression of pineal function sensitizes the ductule cells to the initiation of neoplastic processes and hinders the development of regressive changes.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1997

Reverse "repetition blindness" and release from "repetition blindness": constructive variations on the "repetition blindness" effect.

N. Kanwisher observed that subjects shown rapid lists of words recall two occurrences of a repeated word less often than two unrelated words. Kanwisher explained this "repetition blindness" through a type/token account, which assumes that encoding the second occurrence of a repeated word is inhibited if it occurs too soon after the first. More fundamentally, it assumes that failure to recall a word from a rapid list results from failure to encode its occurrence. Contrary to that interpretation, we observed that subjects can often recognize words that they cannot recall from a rapid list. We also observed "reverse repetition blindness," when the second presentation was given greater contextual support, and a "release from repetition blindness" effect, when distinctive contextual support was given to ech occurrence. We concluded that a constructive account of remembering provides a better explanation of all of the effects.

Adult↗
PubMedDate not supplied

Estimation of blindness in India from 2000 through 2020: implications for the blindness control policy.

BACKGROUND: To eliminate avoidable blindness in India, appropriate national planning is necessary, which should be based on current and reliable data. A national survey done in 1986-89 reported that 1.5% of the Indian population (12 million people) was blind with a presenting visual acuity of < 6/60 in the better eye. The original goal of the National Programme for Control of Blindness was to reduce this prevalence to 0.3% by 2000. We have recently reported the prevalence of blindness in the population of Andhra Pradesh to be 1.66% with a presenting visual acuity of < 6/60 in the better eye as the sole criterion and 1.84% with a presenting visual acuity of < 6/60 orcentral visual field < 20 degrees in the better eye. We used these population-based data to estimate blindness in India in 2000 and project the possible scenarios of blindness through 2020 with different emphases of the blindness control policy in India. METHODS: Recent population-based data on the age-, sex- and cause-specific blindness rates from the Andhra Pradesh Eye Disease Study for the entire age range were applied to the population distribution of India to estimate the number of blind persons in 2000. The age-, sex- and cause-specific rates of blindness were then applied to the estimated age, sex and urban-rural population distribution of India in 2010 and 2020 to project the number of persons blind (from various causes) and the blind person-years that would be suffered under varying degrees of emphasis in the policy to control blindness due to particular diseases. For these projections, blindness was defined as a presenting distance visual acuity of < 6/60 or central visual field < 200 in the better eye. RESULTS: The number of blind persons in India in 2000 was estimated to be 18.7 million (95% confidence interval [CI]: 15.2-22.3), of which 9.5 million were cataract-related and 3 million refractive error-related. If there is no change in the current trend of blindness, the number of blind persons in India would increase to 24.1 million (95% CI: 19.7-28.4) in 2010, and to 31.6 million (95% Cl: 26.4-36.9) in 2020. If effective strategies are put in place to eliminate 95% of blindness due to cataract by 2020, blindness in 15.6 million persons would be prevented who would otherwise be blind in 2020 if the current trend continues, and 78 million blind person-years would be prevented in these persons. Similarly, if effective strategies are also implemented to eliminate 95% of the refractive error blindness by 2020, another 4.2 million persons would be prevented from being blind in 2020, and 82 million blind person-years would be prevented. In addition, if strategies to prevent 90% of the preventable blindness due to corneal disease and glaucoma are successful by 2020, blindness in an additional 3.6 million persons in 2020 and 29 million blind person-years would be prevented. CONCLUSION: The planning of blindness control in India should take into account recent population-based data for the entire age range, which suggest that the number of blind persons in India is currently over 18 million. This estimate is 50% more than the figure of 12 million from a decade ago that is still quoted widely in the blindness control policy documents. If avoidable blindness is to be substantially reduced in India by 2020, effective strategies against blindness due to cataract and refractive error are needed urgently as both these conditions are relatively easy to treat. Also, strategies against preventable corneal and glaucoma blindness need to be strengthened soon for them to show an impact over the next two decades.

Adolescent↗
PubMed2003

Changes in blindness prevalence over 16 years in Malawi: reduced prevalence but increased numbers of blind.

BACKGROUND/AIMS: In the coming two decades significant increases in the burden of blindness are anticipated unless concerted efforts are made to improve eye care in developing countries. Evidence of changing prevalence rates or numbers of blind people are few. The change in blindness prevalence and the number of blind people in an adult population of Malawi was measured over a 16 year period. METHODS: In 1999 a population based survey of blindness in adults (age 50+) was conducted in Chikwawa district of Malawi. Visual acuity and cause of vision loss were recorded for each eye independently. Blindness was defined as presenting better eye vision of <6/60. Findings from a 1983 survey of blindness in the same district (using similar methods) were re-analysed to be comparable with the survey conducted in 1999. RESULTS: Among 1630 enumerated adults 89% were examined. The age adjusted prevalence of blindness in the adult population was 5.4% and more common in women than men. In each age group the prevalence of blindness was lower in 1999 than in 1983; the overall reduction in blindness was 31%. During this period the 50+ population in Malawi increased almost twofold. Extrapolating the Chikwawa district data to the Malawi population reveals that the number of blind people has increased by 24%; the increase is primarily because of the large increase in the size of the most elderly group, aged 70 and above. CONCLUSION: The majority of blind people in Chikwawa (1983 and 1999) are in the age group 70 and over. This group has had the largest proportional increase in population size in this time. Services in this population have improved in the intervening 16 years and yet there was still an increase in the number of blind people. There was little change in excess blindness in women, suggesting that the same barriers that prevented utilisation of services in 1983 probably persist in 1999. Efforts to reach the most elderly and to reach women are needed to lead to a reduction in blind people in settings such as rural Malawi.

Age Distribution↗
PubMed2002

Blindness and glaucoma: a comparison of patients progressing to blindness from glaucoma with patients maintaining vision.

PURPOSE: To compare patients becoming legally blind from glaucoma with those who did not go blind. DESIGN: Retrospective, cohort, and case-control study. METHODS: A retrospective community-based longitudinal study of residents of Olmsted County, Minnesota, who were newly diagnosed with open-angle glaucoma between 1965 and 1980 and followed through 1998. A case-control study was performed comparing patients progressing to legal blindness from glaucoma with aged-matched and visual field-matched patients not progressing to blindness. RESULTS: Fifty-six of 290 patients progressed to legal blindness in at least one eye over the 34-year period of the study. Most who progressed to blindness had moderate to advanced visual field loss at the time of diagnosis of glaucoma. Those becoming legally blind had mean intraocular pressures (IOP) on therapy lower than or similar to patients who did not go blind, although the variability of IOP was higher in the blind group. Different susceptibilities to IOP were apparent, as some eyes with initially normal disks and visual fields became blind at an IOP of 20 mm, while others did not worsen. Changes in medical therapy after progression of visual field damage were less effective in lowering IOP in the group becoming blind than in the nonblind group. CONCLUSIONS: Patients at greatest risk of blindness had visual field loss at the time of diagnosis of glaucoma. Different susceptibilities to IOP were apparent, with some patients becoming blind at pressures that others tolerated without significant progression. This suggests that continued monitoring of visual fields and reassessment of target IOP levels when field damage occurs are fundamental in the management of glaucoma.

Aged↗
PubMed2002

Fear of blindness and perceptions about blind people. The Andhra Pradesh Eye Disease Study.

This study assessed the fear of being affected by illness and disability including blindness, and perceptions of the population towards blind people in the Indian state of Andhra Pradesh. A total of 11,786 subjects of all ages were sampled from 94 clusters in one urban and three rural study areas of Andhra Pradesh using stratified, random, cluster, systematic sampling to represent the population of this state. A total of 10,293 subjects of all ages underwent a detailed interview and dilated ocular evaluation. Subjects > 15 years of age (7,432) were interviewed regarding fear of illness/disability and their perceptions of blind people. The fear of blindness was assessed in comparison to cancer, severe mental illness, heart attack, losing limbs, deafness, inability to speak, and paralysis. A majority of the study population feared all the illnesses and disabilities assessed. The prevalence of fear of blindness was 90.9% (95% confidence interval 89.1-92.8%) and 92.1% (95% confidence interval 90.6-93.6%) in urban and rural study areas respectively. With multiple logistic regression the fear of blindness was significantly higher for those with any level of education and for those living in the rural study areas. The proportion of those having positive feelings towards blind people was higher in the urban study area. A high prevalence of blindness, 1.84%, has been reported in this population previously. These data suggest that this population feared blindness, and yet there is a high rate of blindness. This reflects the need for increasing awareness about blindness in this population through eye health promotion strategies in order to reduce blindness, and awareness regarding the availability of rehabilitation services.

Adaptation, Psychological↗
PubMedDate not supplied

[Prevalence and causes of blindness in the Tunisian Republic. Results of a national survey conducted in 1993. Tunisian Team on the Evaluation of Blindness].

AIMS: to estimate the prevalence of visual impairment and blindness; to identify the major causes of visual impairment and blindness and to estimate their overall impact, particularly on cataracts. METHODS: We used a population-based method. A cluster sample was selected, with the number of households randomly selected from a community depending on the size of the population. Examinations and data collection were carried out using the procedures recommended by the WHO. RESULTS: We included 3,981 individuals, 3,547 of whom were given a medical examination (89% participation). The structure of the sample differed from that of the Tunisian population, with people over the age of 60 years over represented in the sample. The crude prevalence of blindness was 1.2% (adjusted prevalence 0.8%) and that for bilateral visual impairment was 3% (adjusted prevalence 2%). There were 225,000 individuals with severely impaired vision, of whom 64,500 were blind (including 2,100 children under the age of 15 years) and 160,000 were visually impaired (including 8,700 children). Individuals over the age of 60 were eight times more likely to become blind and 6.7 times more likely to suffer visual impairment than those below the age of 60. Cataracts, particularly associated with aging, were the main cause of blindness (66%) and bilateral visual impairment (54.6%). Uncorrected aphakia accounted for a significant fraction of the visual deficiencies identified in this survey (6.4% of cases of blindness and 11.8% of cases of bilateral visual impairment). 1.7% of the individuals examined (135,000 people) had ocular surgery and 80,000 had undergone surgery for cataracts. Only 41% of those individuals who had cataracts had undergone surgery. The provision of cataract surgery was therefore inadequate. CONCLUSION: About 80% of the cases of blindness registered were preventable or treatable. The development of appropriate strategies for dealing with cataract blindness should significantly reduce the incidence of blindness.

Adolescent↗
PubMed1991

How blind is blind review?

BACKGROUND: No representative surveys of scientific opinion about blind review have been published, and there is very little information on the success of the blinding process. The American Journal of Public Health has practiced blind review since 1977. METHODS: In 1989 to 1990 312 of its reviewers were asked to identify author and institution in the manuscript they reviewed, to provide clues to such identification, to express their opinion concerning blind review, and to offer reasons for their opinion. RESULTS: Reviewers claimed to be able to identify author and/or institution in 47% of the 614 chances offered; identification was incorrect 16% of the time, overall identification correct 39% of the time. Self-referencing was the clue to identification in 62%, personal knowledge in 38% of the cases. If only personal knowledge cases are considered, blinding was successful 83% of the time. Blinding was favored by 75% of the reviewers with most asserting it eliminated bias. Reasons given for opposing blind review included the following: blinding not possible, identification will not influence judgment, and its obverse, identification assists judgment. CONCLUSIONS: For the American Journal of Public Health blinding is usually, but not always, successful; and the majority of its reviewers favor current policy. Until more definitive data are in, reviewer preference, which differs from journal to journal, seems the most legitimate guide to journal policy on blind review.

Attitude of Health Personnel↗
PubMed1992

[Cause of blindness in Bavaria. Evaluation of a representative sample from blindness compensation records of Upper Bavaria].

Blindness certificates from the region of Oberbayern were studied to obtain data for the prevalence, incidence and the causes of blindness in Bavaria. This investigation reveals increasing rates for the prevalence and incidence of blindness. Most (60% of the prevalence and 70-80% of the incidence) of the blind are older than sixty years of age. The prevalence (2.5%) and incidence rate for children (blind before 18 years of age) are low. Macular degeneration (15.4%) has the highest prevalence rate followed by glaucoma (14.3%), retinopathia pigmentosa (10.3%), high myopia (11.5%) and optic atrophy (8%). Blindness from diabetic retinopathy accounts for 7.1% of cases. Macular degeneration is also the leading cause of blindness when incidence rates (28%) for all ages are calculated. Lower incidence rates are found for glaucoma (17%) and diabetic retinopathy (13%). For blind children malformations of the eyes (18.7%) are found to be the leading cause of blindness in regard to prevalence figures. The retinopathy of prematurity (17.2%) and complex cerebral disturbances (16.1%) do present with similar figures.

Adolescent↗
PubMed1989

Picture and pattern perception in the sighted and the blind: the advantage of the late blind.

Two experiments are reported on the contribution of visual experience to tactile perception. In the first experiment, sighted, congenitally blind, and late blind individuals made tactual matches to tangible embossed shapes. In the second experiment, the same subjects attempted tactile identification of raised-line drawings. The three groups did not differ in the accuracy of shape matching, but both groups of blind subjects were much faster than the sighted. Late blind observers were far better than the sighted or congenitally blind at tactile picture identification. Four of the twelve pictures were correctly identified by most of the late blind subjects. The sighted and congenitally blind performed at comparable levels in picture naming. There was no evidence that visual experience alone aided the sighted in the tactile task under investigation, since they performed no better than did the early blind. The superiority of the late blind suggests that visual exposure to drawings and the rules of pictorial representation may help tactile picture identification when combined with a history of tactual experience.

Adult↗
PubMed1999

Causes of childhood blindness in the People's Republic of China: results from 1131 blind school students in 18 provinces.

AIMS: To determine the anatomical site and underlying causes of blindness and severe visual impairment in children under 16 years of age in special education in the People's Republic of China with a view to determining potentially preventable and treatable causes. METHODS: A national study of children attending schools for the blind in China was conducted between April and June 1998 using the WHO Prevention of Blindness Programme (WHO/PBL) eye examination record for children with blindness and low vision. Eight Chinese ophthalmologists attended a training workshop before conducting the study. 36 blind schools in 18 provinces of China were included. RESULTS: 1245 children aged between 5 and 15 years were examined, of whom 1131 (91%) were blind or severely visually impaired (visual acuity less than 6/60 in the better eye). The commonest anatomical sites of visual loss were whole globe (mainly microphthalmos) 25.5% and retina (mainly dystrophies) 24.9%. Lens was the major site in 18. 8%, optic nerve in 13.6%, and glaucoma in 9%. Corneal scarring was not a major cause of visual loss. The aetiology was unknown in 52.9%, hereditary factors were responsible in 30.7%, and childhood causes in 14%. 15% of cases were considered potentially preventable and 22. 5% potentially treatable. CONCLUSION: The pattern of childhood blindness seen in this study is likely to reflect the improved health and socioeconomic status of China but may partly reflect bias in admission to, and location of, blind schools, with higher socioeconomic groups overrepresented. Nutritional and infective causes of blindness are uncommon, and hereditary and unknown factors are now the predominant causes.

Adolescent↗
PubMed2003

Causes of childhood blindness: results from schools for the blind in south eastern Nigeria.

AIM: This cross sectional study was undertaken to identify the major causes of childhood severe visual impairment/blindness (SVI/BL) among students in schools for the blind in south eastern Nigeria with a view to offering treatment to those with remediable blindness. METHODS: 142 students attending three schools for the blind in the study area were interviewed and examined using the World Health Organization programme for prevention of blindness (WHO/PBL) childhood blindness proforma. RESULTS: By anatomical classification, the major causes of SVI/BL identified in the children (aged 15 years or less) were lesions of the lens (30.4%), corneal lesions (21.7%), whole globe lesions (mainly phthisis bulbi) (17.4%), and glaucoma/buphthalmos (10.9%). For the young adults (more than 15 years) these lesions accounted for 31.9%, 21.3%, 23.4%, and 8.5% of SVI/BL, respectively. For all the students, the commonest single diagnoses were cataract (23.5%) and corneal scarring (21.4%), of which 86.7% were caused by measles. By aetiological classification, childhood factors (38.6%) constituted the major cause of blindness: 37.0% in the children and 39.4% in the young adults. In 74.5% of all the students, blindness was considered avoidable. CONCLUSIONS: A high proportion of childhood blindness in schools for the blind in south eastern Nigeria is avoidable. Development of paediatric ophthalmology in Nigeria to manage childhood cataract and glaucoma is advocated.

Adolescent↗
PubMed2003

Causes of blindness at the "Wiyata Guna" School for the Blind, Indonesia.

AIM: To determine the anatomical site and patterns of cause of blindness in one of the biggest schools for the blind in Indonesia with a view to determining potentially preventable and treatable causes. METHODS: 165 students in one school for the blind in Bandung, Indonesia, were examined clinically and data reported using the WHO/PBL childhood blindness assessment form. RESULTS: Most of the students (96.4%) were blind (BL); 3% were severely visually impaired (SVI). The major causes of SVI/BL in this study were: (1) corneal staphyloma, corneal scar, and phthisis bulbi (mainly attributed to infection) in 29.7%; (2) retinal dystrophies (mainly Leber congenital amaurosis, early onset retinitis pigmentosa) in 20.6%; (3) congenital and familial cataract (13.3%); (4) microphthalmus, anophthalmus (10.9%). The whole globe was the major anatomical site of visual loss (32.7%), followed by the retina (26.0%), cornea (17.6%), lens (13.3%), optic nerve (6.1%), and uvea (4.3%). CONCLUSIONS: This is a small study in a selected population and the results should be interpreted with caution. This blind school study, adopting the WHO/PBL eye form for data analysing, is the first reported for Indonesia. Hereditary disease and infective causes of blindness are the predominant causes of blindness, accounting for 42.4% and 29.7%, respectively. This pattern of causes is a mixed pattern which lies in an intermediate position between the patterns seen in developing countries and those seen in developed countries. The importance both of preventive public health strategies and of specialist paediatric ophthalmic and optical services in the management of childhood blindness in Indonesia are therefore strongly suggested to cover the problems that exist.

Blindness↗