SEARCH · Search PubMed

Results for “VISION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources

PubMed1999

Is vision continuous with cognition? The case for cognitive impenetrability of visual perception.

Although the study of visual perception has made more progress in the past 40 years than any other area of cognitive science, there remain major disagreements as to how closely vision is tied to cognition. This target article sets out some of the arguments for both sides (arguments from computer vision, neuroscience, psychophysics, perceptual learning, and other areas of vision science) and defends the position that an important part of visual perception, corresponding to what some people have called early vision, is prohibited from accessing relevant expectations, knowledge, and utilities in determining the function it computes--in other words, it is cognitively impenetrable. That part of vision is complex and involves top-down interactions that are internal to the early vision system. Its function is to provide a structured representation of the 3-D surfaces of objects sufficient to serve as an index into memory, with somewhat different outputs being made available to other systems such as those dealing with motor control. The paper also addresses certain conceptual and methodological issues raised by this claim, such as whether signal detection theory and event-related potentials can be used to assess cognitive penetration of vision. A distinction is made among several stages in visual processing, including, in addition to the inflexible early-vision stage, a pre-perceptual attention-allocation stage and a post-perceptual evaluation, selection, and inference stage, which accesses long-term memory. These two stages provide the primary ways in which cognition can affect the outcome of visual perception. The paper discusses arguments from computer vision and psychology showing that vision is "intelligent" and involves elements of "problem solving." The cases of apparently intelligent interpretation sometimes cited in support of this claim do not show cognitive penetration; rather, they show that certain natural constraints on interpretation, concerned primarily with optical and geometrical properties of the world, have been compiled into the visual system. The paper also examines a number of examples where instructions and "hints" are alleged to affect what is seen. In each case it is concluded that the evidence is more readily assimilated to the view that when cognitive effects are found, they have a locus outside early vision, in such processes as the allocation of focal attention and the identification of the stimulus.

Agnosia↗

PubMed2002

Is vision function related to physical functional ability in older adults?

OBJECTIVES: To assess the relationship between a broad range of vision functions and measures of physical performance in older adults. DESIGN: Cross-sectional study. SETTING: Population-based cohort of community-dwelling older adults, subset of an on-going longitudinal study. PARTICIPANTS: Seven hundred eighty-two adults aged 55 and older (65% of living eligible subjects) had subjective health measures and objective physical performance evaluated in 1989/91 and again in 1993/95 and a battery of vision functions tested in 1993/95. MEASUREMENTS: Comprehensive battery of vision tests (visual acuity, contrast sensitivity, effects of illumination level, contrast and glare on acuity, visual fields with and without attentional load, color vision, temporal sensitivity, and the impact of dimming light on walking ability) and physical function measures (self-reported mobility limitations and observed measures of walking, rising from a chair and tandem balance). RESULTS: The failure rate for all vision functions and physical performance measures increased exponentially with age. Standard high-contrast visual acuity and standard visual fields showed the lowest failure rates. Nonstandard vision tests showed much higher failure rates. Poor performance on many individual vision functions was significantly associated with particular individual measures of physical performance. Using constructed combination vision variables, significant associations were found between spatial vision, field integrity, binocularity and/or adaptation, and each of the functional outcomes. CONCLUSIONS: Vision functions other than standard visual acuity may affect day-to-day functioning of older adults. Additional studies of these other aspects of vision and how they can be treated or rehabilitated are needed to determine whether these aspects play a role in strategies for reducing disability in older adults.

Activities of Daily Living↗

PubMedDate not supplied

Prevalence of remediable disability due to low vision among institutionalised elderly people.

BACKGROUND: Prevalence of remediable visual disability among institutionalised elderly people, resulting from inappropriate use or non-use of low-vision aids, is reported to be high, but largely rests on anecdotal evidence. OBJECTIVE: To estimate the prevalence of binocular low vision and underlying eye diseases among institutionalised elderly people in a Dutch urban population and the size of remediable visual disability as the result of inappropriately corrected low vision. METHODS: The design was a cross-sectional survey of 284 subjects with low vision (corrected binocular vision <0.4) in nursing homes and homes for the elderly in the Netherlands. RESULTS: 284 of 610 eligible residents were examined. The prevalence of binocular low vision was 31.3%. Among elderly residents with low vision, prevalence of cataract, age-related macular degeneration, glaucoma, and diabetic retinopathy was 77.9, 37.7, 5.2 and 5.2%, respectively. In 32 residents (41.6%), (non)-use of low-vision aids was considered inappropriate. In 50 residents (64.9%), visual disability was considered at least partially remediable, either through better use of low-vision aids, or through cataract extraction. Residents who were not optimally corrected for low vision were significantly more functionally impaired compared with their peers who were optimally corrected. CONCLUSION: Low vision is likely to be highly prevalent among institutionalised elderly. A significant amount of the associated visual disability may be remediable.

Aged↗

PubMed2006

Need for optical and low vision services for children in schools for the blind in North India.

CONTEXT: Children admitted in blind schools need low vision assessment for improving functional vision (useful residual vision). AIM: To ascertain the need for spectacles and magnifiers as low vision devices (LVD) in children with useful residual vision, attending blind schools. SETTING AND DESIGN: Cross-sectional study conducted in 13 blind schools in Delhi, North India. MATERIALS AND METHODS: Of a total of 703 children (less than 16 years of age) examined, 133 (18.91%) with useful residual vision were refracted and analyzed. High addition plus lenses (range 5-30 diopters) were used as spectacle magnifiers for near LVD assessment. "World health organization (WHO)/ prevention of blindness (PBL) eye examination record for children with blindness and low vision", was used to collect data. SPSS (statistical package for the social science), version 10.0 was used for analysis. RESULTS: Based on the vision of 133 children at initial examination, 70.7% children were blind and 12.0% were severely visually impaired (SVI). 20.3% children improved by at least one WHO category of blindness after refraction. With best correction, 50.4% children were still blind and 13.5% were SVI. Visual acuity in the better eye after refraction in 47 children (35.3%), improved with spectacles. Children with aphakia (17), coloboma (5), refractive error (5) and microphthalmos (4) benefited from spectacles. Of 124 children with low vision but having useful residual vision, 51 (41.1%) were able to read N-10 unaided or with distance spectacles and 30 children (22.6%) improved to N-10 with spectacle magnifiers and were prescribed the same. CONCLUSION: Visually impaired children with aphakia and congenital anomalies of the eye benefit from refraction and low vision services.

Adolescent↗

PubMed1995

Care plan assessment of visual status and evaluated vision among nursing home residents.

OBJECTIVE: To compare the comprehensive care plan assessment (Minimum Data Set, MDS) of vision with the clinically evaluated visual status of nursing home residents to determine the accuracy of the vision care plan. DESIGN: Descriptive study. SETTING: One publicly funded and four privately owned long-term care nursing facilities. PARTICIPANTS: 151 nursing home residents undergoing vision examination at the nursing home request. Mean age of 81, range 34 to 97 years. MAIN OUTCOME MEASURE: The charted MDS assessment for vision patterns was compared with the MDS plan which would have been formulated based on direct clinical vision examination. Determinations were made based on the three areas required by MDS: visual acuity (VA), peripheral vision, and presence of prosthetic visual devices. CONCLUSIONS: The MDS care plan for vision and actual visual status agreed in only 34% (52/151) of persons. The Vision (VA) subsection overestimated VA in 41% and underestimated VA in 11%. Concordance for VA was extremely poor (kappa 0.176). In no participants did the MDS indicate a visual field defect, whereas 16.5% (25/151) did show visual field restriction on examination. Care plan assessments also failed to note the use of visual prosthetic devices in 17% (26/151). These results indicate that MDS care plan assessment for vision is often inaccurate and may result in the lack of appropriate vision care being triggered through resident assessment protocols (RAP).

Adult↗

PubMed1999

Optical penalization can improve vision after occlusion treatment.

BACKGROUND: Optical penalization (OP) has previously been shown to successfully maintain vision in amblyopic eyes of older children when patching compliance is poor and when vision decreases once patching is discontinued. This study shows that the final vision in optically penalized eyes is often better than the vision obtained after patching alone. SUBJECTS AND METHODS: During the 5-year period from January 1992 to February 1997, 28 children aged between 3.7 and 8.2 years (average age, 6.5+/-1.1 years) were optically penalized for an average of 1.5+/-0.75 years. The maximum length of penalization was 3.3 years, whereas the minimum time was 6 months. There were 21 children with strabismic amblyopia and 7 children with anisometropic amblyopia. All 28 children had worn a patch to achieve their best visual levels and then had shown a loss of best vision when occlusion was stopped. Patching was usually resumed and continued until the previous best vision was obtained; at this point OP was started to "maintain" vision. Eighteen of the 28 children have discontinued penalization and have been followed up an average of 1(1/2) years. RESULTS: Twenty-six (93%) of the 28 patients showed an increase in best vision from that found at the conclusion of patching, and 2 patients maintained their vision at the initial level. The average visual acuity at the start of penalization was 20/50 (0.42+/-0.11 logarithm of the minimum angle of resolution [log MAR]). Final average visual acuity was 20/27 (0.15+/-0.12 log MAR). The average increase in vision was nearly 3 lines or 0.27+/-0.12 log MAR. CONCLUSION: OP alone (without the use of pharmacologic agents such as atropine) not only maintains vision after patching therapy, but also appears to improve the final visual outcome.

Amblyopia↗

PubMed2000

Motorist vision policy.

BACKGROUND: The primary purpose of public policy requiring vision testing for driver license renewal is to identify individuals with functional vision impairments and, when necessary, to restrict their driving. This is based on the presumption that poor vision is causally related to poor driving and traffic crashes. METHODS: The AOA Environmental and Occupational Vision Committee performed a synthesis of relevant empirical literature on policy-based research and developed potential options for enhancing traffic safety. RESULTS: Presently, some states require vision testing for driver's license renewal and some do not. Regional and nationwide studies report that vision-related license renewal policies are associated with enhanced traffic safety. However, contemporary vision screening tests may be of limited value in identifying individuals with functional vision impairments. CONCLUSION: The most cost-effective and valid method for identifying, treating and counseling visually impaired drivers is to require a comprehensive eye examination as a condition for driver license renewal for those with a high prevalence or high probability of vision impairment.

Accidents, Traffic↗

PubMed1985

Psychophysics of reading--II. Low vision.

Very little is known about the effects of visual impairment on reading. We used psychophysical methods to study reading by 16 low-vision observers. Reading rates were measured for text scanned across the face of a TV monitor while varying parameters that are likely to be important in low vision: angular character size, number of characters in the field, number of dots composing each character, contrast polarity (white-on-black vs black-on-white text), and character spacing. Despite diverse pathologies and degrees of vision loss in our sample, several major generalizations emerged. There is a wide variation in peak reading rates among low-vision observers, but 64% of the variance can be accounted for by two major distinctions: intact central fields vs central-field loss and cloudy vs clear ocular media. Peak reading rates for observers with central-field loss were very low (median 25 words/minute), while peak reading rates for observers with intact central fields were at least 90 words/minute (median 130 words/minute). Most low-vision readers require magnification to obtain characters of optimal size. Sloan M acuity was a better predictor of optimal character size than Snellen acuity, accounting for 72% of the variance. Low-vision reading is similar to normal reading in several respects. For example, both show the same dependence on the number of characters in the field. Our results provide estimates of the best reading performance to be expected from low-vision observers with characteristic forms of vision loss, and the stimulus parameters necessary for optimal performance. These results will be useful in the development of clinical tests of low vision, and in the design of low-vision reading aids.

Adolescent↗

PubMed2002

Planning low vision services in India : a population-based perspective.

OBJECTIVE: To assess the prevalence and causes of low vision in a population in southern India for planning low vision services. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: A total of 10,293 persons of all ages from 94 clusters representative of the population of the Indian state of Andhra Pradesh. METHODS: The participants underwent a detailed eye examination, including measurement of visual acuity with logarithm of the minimum angle of resolution charts, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, and stereoscopic dilated fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were done when indicated using predefined criteria. MAIN OUTCOME MEASURES: Low vision was defined as permanent visual impairment that was not correctable with refractive error correction or surgical intervention. The participants with best-corrected distance visual acuity <6/18 to perception of light or central visual field <10 degrees because of an untreatable cause in both eyes were considered as having low vision. RESULTS: Low vision was present in 144 participants, an age, gender, and urban-rural distribution adjusted prevalence of 1.05% (95% confidence interval, 0.82%-1.28%). The most frequent causes of low vision included retinal diseases (35.2%), amblyopia (25.7%), optic atrophy (14.3%), glaucoma (11.4%), and corneal diseases (8.6%). Multivariate analysis showed that the prevalence of low vision was significantly higher with increasing age, and there was a trend for higher prevalence with decreasing socioeconomic status. Extrapolating these data to the estimated 1014 million population of India in the year 2000, 10.6 (95% confidence interval, 8.4-12.8) million people would have low vision. CONCLUSIONS: These data imply that there is a significant burden of low vision in this population, suggesting the need for low vision services.

Adolescent↗

PubMed2005

Evaluation of the traveling vision examiner program in the submacular surgery trials pilot study.

PURPOSE: To describe methods and results and to assess the value of a Traveling Vision Examiner (TVE) Program designed to provide masked vision measurements by expert vision examiners who were independent of, and traveled to, local clinical centers. METHODS: The Submacular Surgery Trials (SST) Pilot Study was conducted to refine the design and methods for a set of multicenter, randomized clinical trials to evaluate submacular surgery in patients with subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration (AMD) or ocular histoplasmosis (OHS), or idiopathic CNV in which the primary study outcome would be change in 2-year best-corrected vision from baseline. As part of the SST Pilot Study, the feasibility and value of a TVE Program was assessed. The goal of the program was to obtain unbiased vision measurements, according to a standard protocol, of best-corrected visual acuity, reading speed, and contrast threshold, of each patient at 2 and 4 years after enrollment. RESULTS: Eighty-three visits by TVEs were made to 16 centers participating in the SST Pilot Study; 239 patients had at least one masked vision examination. Comparison of pairs of vision measurements of the traveling vision examiners and local vision examiners for 71 patients made on the same day showed good agreement overall (intraclass correlation coefficient > or = 0.81). CONCLUSIONS: The proposed TVE Program was judged to be a feasible and useful method of providing standardized, unbiased, masked vision measurements. This approach was incorporated into the larger clinical trials conducted by the SST Research Group.

Choroidal Neovascularization↗

PubMed2001

The frequency of perioperative vision loss.

UNLABELLED: The frequency of perioperative vision loss, especially for spinal surgery, has been increasing recently. We undertook a retrospective study to determine the frequency of this outcome in a large surgical population receiving general or central neuraxis regional anesthesia for noncardiac procedures from 1986 to 1998. Specific criteria were used to separate cases in which the surgical procedure likely directly contributed to the vision loss. Vision loss was present if any part of the visual field was affected. Initial database screening found 405 cases of new-onset vision loss or visual changes in 410,189 patients who underwent 501,342 anesthetics and who survived at least 30 days after their final procedures. Two hundred sixteen of these patients regained full vision or acuity within 30 days. Of the 189 patients who developed vision deficits for longer than 30 days, 185 underwent ophthalmologic or neurologic procedures in which ocular or cerebral tissues were surgically damaged or resected. The remaining 4 patients (1 per 125,234 overall; 0.0008%) developed prolonged vision loss without direct surgical trauma to optic or cerebral tissues. In this large study population of noncardiac surgical patients, including those who underwent spinal surgical procedures, the frequency of perioperative vision loss persisting for longer than 30 days was very small. IMPLICATIONS: Vision loss and blindness after surgery and anesthesia is a very rare event. In this study, only one per 125,234 patients undergoing noncardiac surgery developed vision loss persisting for longer than 30 days.

Adolescent↗

PubMed2002

Acute vision impairment: does it affect an anesthesiologist's ability to intubate the trachea?

UNLABELLED: The result of impaired vision on an anesthesiologist's ability to intubate the trachea is unknown. We studied 12 attending staff anesthesiologists as they intubated 2 anesthesia mannequins (A and B) under 6 conditions. The conditions were: 1) usual vision, 2) central-vision loss with 20/500 bilaterally and a 24 degrees central scotoma, 3) peripheral-field loss with 20/20 bilaterally and a 7 degrees visual field, 4) peripheral-field loss with 20/20 bilaterally and a 3.5 degrees visual field, 5) central-vision loss with 20/200 bilaterally and a 12 degrees central scotoma, and 6) right eye ocular media opacity and 20/70 left eye usual acuity. The time to intubation was recorded by stopwatch from gripping the laryngoscope until the anesthesiologist signaled that the endotracheal tube was properly placed in the trachea. The mean +/- SD times to intubation for Mannequins A and B were 16.0 +/- 3.3, 31.9 +/- 10.4, 26.4 +/- 9.0, 26.4 +/- 7.7, 22.4 +/- 5.1, 25.5 +/- 16.9 and 16.6 +/- 6.6, 26.9 +/- 10.0, 21.4 +/- 9.2, 21.4 +/- 5.8, 21.5 +/- 7.7, 17.7 +/- 5.1 s for the 6 conditions, respectively. Multiple analysis of variance revealed a highly significant difference for the time to successful intubation between the anesthesiologists' usual vision and the vision-impaired conditions. There was a significant improvement in time to successful intubation from the first to subsequent intubation attempts. There were also more esophageal intubations in the vision-impaired conditions. This implies that anesthesiologists who develop acute severe vision impairment might have more difficulty intubating the trachea, which could initiate more critical incidents. The results of this study cannot be applied to anesthesiologists with chronic vision impairment. IMPLICATIONS: We found that acute severe vision impairment adversely affects the anesthesiologist's ability to intubate the trachea. This implies that anesthesiologists with acute onset of severe visual handicaps might have more difficulty intubating the trachea, which could initiate more critical incidents.

Acute Disease↗

PubMed1998

Potential human and economic cost-savings attributable to vision testing policies for driver license renewal, 1989-1991.

PURPOSE: This study assessed the impact of vision-related relicensing policies on traffic fatalities in the United States. There is a limited empirical basis for state vision testing policies for relicensing. Furthermore, it is uncertain whether contemporary vision standards for driver licensing achieve their implicit goal of protecting the public's health, or inappropriately restrict the mobility of competent drivers. METHODS: The 48 contiguous states and the District of Columbia were the "subjects" in this investigation. During the study period (1989 to 1991), 10 states did not require vision testing for driver license renewal. Multiple regression modeling was used to assess the impact of vision-related relicensing policies on traffic safety and to estimate the number of avoidable vehicle occupant fatalities and corresponding economic costs associated with traffic crashes involving older drivers (> or = 60 years). The primary data source for this investigation was the Fatal Accident Reporting System (FARS) database. RESULTS: Vision-related relicensing policies were significantly associated (p < 0.05) with lower vehicle occupant fatality rates of older drivers. According to the final regression model, approximately 222 fewer vehicle occupant fatalities (-12.2%) associated with older drivers would be expected for the 3-year period if mandatory vision testing policies had been in effect in 8 of the 10 states without such policies. Conservatively, those avoidable deaths represent an estimated $31 million in avoidable economic costs. CONCLUSIONS: State-level mandatory vision testing for relicensure may enhance traffic safety and reduce the economic burden of fatal crashes. Vision testing requirements should be maintained by jurisdictions with such requirements, and jurisdictions without such requirements should consider the potential traffic safety benefits of vision testing for driver license renewal.

Accidents, Traffic↗

PubMed2002

A model of the prevalence and incidence of low vision and blindness among adults in the U.S.

Population-based vision screening studies of the prevalence rate of low vision and blindness in the U.S. are reviewed to evaluate the sources of disagreement among studies. The major reasons that studies disagree on prevalence rate estimates are differences in best-corrected visual acuity criteria for low vision and differences in the age range of the oldest age category. When corrections are made for these differences, the results of all prevalence rate studies, except the Mud Creek Valley Study, fit the same prevalence rate vs. age function. The greater prevalence rate of low vision and blindness for each age category that was observed in the Mud Creek Valley Study can be attributed to the higher prevalence rate of cataract associated with a paucity of health care services in the Mud Creek Valley population. The time-derivative of the prevalence rate vs. age function fit to the data provided an estimate of the annual incidence rate of low vision and blindness vs. age. The estimated annual incidence agreed with estimates from unpublished 8-year incidence data of the Baltimore Eye Survey. The incidence rate of low vision and blindness for Americans aged 40 to 60 years is higher among blacks than among whites. For Americans greater than age 60 years, the incidence rate for whites exceeds that for blacks. This observation probably reflects the different natural histories of glaucoma, a leading cause of low vision and blindness among black Americans, and age-related macular degeneration, a leading cause of low vision and blindness among white Americans. Using the age-dependent models of prevalence rate of low vision and blindness for white and black populations, an estimated 1.5 million Americans over age 45 years have a best-corrected visual acuity in the better eye that is < or = 20/70. Based on the incidence rate estimates, approximately 240,000 new cases of low vision and blindness occur each year. With the aging of the U.S. population, that number is expected to double over the next 25 years.

Adult↗

PubMed1986

Spatial and temporal properties of human rod vision in the achromat.

The spatial and temporal properties of rod vision were measured for stimuli at and above the detection threshold in an achromat whose spectral sensitivity, dark adaptation, spatial and temporal thresholds and Stiles-Crawford effect suggest the presence of only a normally functioning rod system. The properties of rod and cone vision were compared at illuminances where their respective sensitivities were optimum. The threshold spatial sensitivity of the rod mechanism under optimum illumination (180 scotopic trolands) exhibits bandpass properties with a peak sensitivity of around 80 at 0.5 cycles/deg and a spatial acuity of 6-7 cycles/deg. The threshold temporal sensitivity also exhibits bandpass properties under these conditions with a peak sensitivity of around 80 at 5 Hz and a temporal acuity of 30 Hz. For stimuli of low spatial frequency (less than 0.3 cycles/deg) and low temporal frequency, the threshold sensitivities of rod- and cone-mediated vision are identical. Rod- and cone-mediated vision display comparable spatial and temporal discrimination for targets of equal suprathreshold contrast over the low to mid spatial and temporal range that they share. Rod-mediated discriminations fall below those of cone vision above 1 cycle/deg for spatial judgements and above 15 Hz for temporal judgements. The number of discriminable steps in spatial frequency and temporal frequency at threshold is similar for rod and cone vision over the spatio-temporal frequency range that they share. Over this range rod- and cone-mediated vision can discriminate four steps in spatial frequency and one step in temporal frequency. These results suggest that rod vision shows comparable spatio-temporal discrimination performance to cone vision and that it is subserved by at least five spatial and two temporal labelled detectors. The response of the highest spatial frequency filter subserving rod vision extends from 0.5 to 6 cycles/deg.

Color Vision Defects↗

PubMed2000

Helping blind and partially sighted people to read: the effectiveness of low vision aids.

AIMS: To substantiate the claim that low vision aids reduce the degree of disability associated with visual impairment. METHODS: An observational study of vision, ocular pathology, age, sex, and reading ability in new referrals to a low vision clinic. Reading ability was assessed both with the patients' own spectacles and with an appropriate low vision aid. RESULTS: The reading performance and biographical characteristics of new referrals to a low vision clinic were recorded. Data were collected for 168 people over a 6 month period. Upon arrival at the clinic the mean functional visual acuity equated to 6/36 and 77% of patients were unable to read newsprint (N8). After a low vision assessment and provision of a suitable low vision aid 88% of new patients were able to read N8 or smaller text. CONCLUSIONS: The degree of visual impairment observed in new referrals to a low vision clinic is sufficient to prevent the majority from performing many daily tasks. Low vision aids are an effective means of providing visual rehabilitation, helping almost nine out of 10 patients with impaired vision to read.

Adolescent↗

PubMedDate not supplied

Blindness and low vision in adults in Ozoro, a rural community in Delta State, Nigeria.

BACKGROUND: The objective of this article is to determine the prevalence and causes of blindness and low vision in Ozoro, a rural town of Delta State in Nigeria, in order to provide baseline information for planning a prevention of blindness programme. METHODS: A cross sectional study using a stratified random sampling method was used to select the compounds. The five communities in the town formed the different sub-groups or strata. Visual acuity were recorded for all adults 40 years and older. Persons who had visual acuity less than 6/18 were further examined to determine the cause of low vision or blindness. The WHO definition of visual impairment according to visual acuity was used as criteria for classification. RESULTS: A total of 815 persons (coverage of 51.7%) were examined using a modified WHO PBL record of blindness form. The prevalence of blindness (VA < 3/60 in the better eye) for people of 40 years and above was 6.3% (95% CI, 4.6% to 8%) and low vision VA 6/24 to 3/60 in the better eye was 25.2%. The estimated prevalence of bilateral blindness for all ages was 1.3% and low vision was 5%. The rate of blindness and low vision increased with age being highest in subjects who were 60 years and above. The main causes of blindness and low vision were cataract, accounting for 60% of all bilateral blindness and 51.7% of all low vision. Other causes of blindness include, posterior segment diseases (11.7%). Glaucoma was presumed to be cause of blindness in 9.8% of cases; others were uncorrected aphakia 5.9%, and globe abnormalities 5.9%. Refractive error was the second major cause of low vision accounting for 22% of bilateral low vision. CONCLUSION: The magnitude of blindness and low vision in this oil rich Ozoro community in Delta State is high and majority are avoidable causes of blindness.

Adult↗

PubMed2000

Iowa's pediatric low-vision services.

BACKGROUND: Reports in the literature concerning best practice for the evaluation and management of children with visual impairments are limited, with a resulting lack of information concerning the potential for optimizing vision to enhance general development and assist with the educational needs of this population. METHOD: The development of a multidisciplinary approach to provide low-vision services for children with visual impairment has occurred over the past 18 years in Iowa. In that time, 1,348 children from around the state of Iowa have been evaluated through an itinerant low-vision service program, coordinated by the Iowa Braille School. RESULTS: A low-vision clinic model--designed to provide services (primarily) for academic students--was not meeting the needs of the pediatric low-vision population in the state. After a statewide review of the program, changes were made that have resulted in low-vision services being provided to a greater and more diverse number of students. The roles of the various members of the multidisciplinary team will be reviewed. Changes in large-print orders and use by special education teachers in the state as a direct result of the low-vision services will also be discussed. CONCLUSION: Ongoing, comprehensive multidisciplinary low-vision services--including optometric low-vision care as a key component--are necessary to help children with visual impairments meet their educational, vocational, and avocational needs. With ongoing low-vision services, unnecessary costs such as those associated with large-print materials can be reduced, thereby creating significant savings to local, state, and federal special educational services.

Child↗