[The statistical variation method of testing the field of vision in normal persons and narrowing of the field of vision in patients with glaucoma].
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Analysis of Variance↗
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[Color vision of children: studies on development of the color discrimination ability and blue vision--discussion on hue arrangement test (author's transl)].
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Child↗
[Study on saturation discrimination by Lovibond Colour Vision Analyser. I. Colour vision of normal subjects (author's transl)].
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Adolescent↗
Vision 21 Delphi panel: senior Army Medical Service Corps Officers' vision of behaviors for success of future Medical Service Corps officers.
A Delphi study was conducted of Army senior Medical Service Corps leaders (O6s) to identify the expected behaviors and competencies needed to ensure that junior officers will achieve successful careers as Medical Service Corps officers in the 21st century. A Delphi mailing was conducted in two phases. In the first iteration, 41 behaviors were identified to be of importance. In the second mailing, the 41 behaviors were rated for relative importance on a 7-point bipolar rating scale (1 = unimportant, 7 = most important). Comparisons were made between the ratings of administrative and biomedical scientific/technical (BS/T) series. Discriminant models developed to compare demographics between administrative and BS/T officers indicated that administrative officers had more time in grade, years of service, and professional military education, whereas BS/T officers reported significantly more civilian education. Minor differences among the two groups emerged for behavior ratings; however, the final priority order of behaviors reflected a high degree of consensus from both groups.
Clinical Competence↗
Barriers to accessing low vision services.
AIM: To investigate barriers to accessing low vision services in Australia. METHODS: Adults with a vision impairment (<6/12 in the better eye and/or significant visual field defect), who were current patients at the Royal Victorian Eye and Ear Hospital (RVEEH), were interviewed. The questions investigated self-perceived vision difficulties, duration of vision loss and satisfaction with vision and also examined issues of awareness of low vision services and referral to services. Focus groups were also conducted with vision impaired (<6/12 in the better eye) patients from the RVEEH, listeners of the Radio for the Print Handicapped and peer workers at Vision Australia Foundation. The discussions were recorded and transcribed. RESULTS: The questionnaire revealed that referral to low vision services was associated with a greater degree of vision loss (p = 0.002) and a greater self-perception of low vision (p = 0.005) but that referral was not associated with satisfaction (p = 0.144) or difficulties related to vision (p = 0.169). Participants with mild and moderate vision impairment each reported similar levels of difficulties with daily activities and satisfaction with their vision (p > 0.05). However, there was a significant difference in the level of difficulties experienced with daily activities between those with mild-moderate and severe vision impairment (p < 0.05). The participants of the focus groups identified barriers to accessing low vision services related to awareness of services among the general public and eye care professionals, understanding of low vision and the services available, acceptance of low vision, the referral process, and transport. CONCLUSION: In addition to the expected difficulties with lack of awareness of services by people with low vision, many people do not understand what the services provide and do not identify themselves as having low vision. Knowledge of these barriers, from the perspective of people with low vision, can now be used to guide the development and content of future health-promotion campaigns.
Activities of Daily Living↗
Principles of modern low vision rehabilitation.
Low vision rehabilitation is a new emerging subspecialty drawing from the traditional fields of ophthalmology, optometry, occupational therapy, and sociology, with an ever-increasing impact on our customary concepts of research, education, and services for the visually impaired patient. A multidisciplinary approach and coordinated effort are necessary to take advantage of new scientific advances and achieve optimal results for the patient. Accordingly, the intent of this paper is to outline the principles and details of a modern low vision rehabilitation service. All rehabilitation attempts must start with a first hand interview (the intake) for assessing functionality and priority tasks for rehabilitation, as well as assessing the patient's all-important cognitive skills. The assessment of residual visual functions follows the intake and offers a unique opportunity to measure, evaluate, and document accurately the extent of functional loss sustained by the patient from disease. An accurate assessment of residual visual functions includes assessment of visual acuity, contrast sensitivity, binocularity, refractive errors, perimetry, oculomotor functions, cortical visual integration, and light characteristics affecting visual functions. Functional vision assessment in low vision rehabilitation measures how well one uses residual visual functions to perform routine tasks, using different items under various conditions, throughout the day. Of the many functional vision skills known, reading skills is an obligatory item for all low vision rehabilitation assessments. Results of assessment guide rehabilitation professionals in developing rehabilitation plans for the individual and recommending appropriate low vision devices. The outcome from assessing residual visual functions is detection of visual functions that can be improved with the use of optical devices. Methods for prescribing devices such as image relocation with prisms to a preferred retinal locus, field displacement to primary gaze position, field expansion, and manipulation of light are practiced today in addition to, or instead of, magnification. Correction of refractive errors, occlusion therapy, enhancement of oculomotor skills, and field restitution are additional methods now available for prescribing devices leading to rehabilitation of visual functions. The outcome from assessing residual functional vision is detection of functional vision that can be improved with the use of vision therapy training. After restoration of optimal residual visual functions is achieved with optical devices, one can follow with training programs for restoration of lost vision-related skills. If an optical dispensary is available where prescribing of low vision devices routinely take place, this will help ensure familiarity and specialization of the dispensary and staff with low vision devices and their special dispensing requirements. The dispensing of low vision devices is an opportunity to introduce the device to the patient, train the patient in the correct use of the device for the task selected, and create a direct and continuous connection with the patient until the next encounter. Following assessment, prescribing, and dispensing of devices, a low vision practitioner, ophthalmologist or optometrist, is responsible for recommending and prescribing vision therapy training to improve residual functional vision. An attempt to present a template for a comprehensive modern low vision rehabilitation practice is made here by summarizing scientific developments in the field and stressing the multidisciplinary involvement required for this kind of practice. It is hoped that this paper and other initiatives from colleagues, the public, and government will promote and raise awareness of modern low vision rehabilitation for the benefit of all.
Humans↗
Clinical effect of low vision aids.
The number of patients with low vision is increasing as life expectancy increases. In addition, the interest and demand for low vision aids are also increasing with improved socioeconomic status and the development of mass media. Therefore, it is imperative to recognize the importance of low vision aids. We reviewed the clinical records of 118 patients who visited our low vision clinic more than twice. According to the data analyzed, optic nerve atrophy, retinal degeneration, diabetic retinopathy and age-related macular degeneration were the most common causes of low vision in these patients. The best corrected visual acuities without low vision aids were less than 0.3, but with the help of low vision aids, vision improved to more than 0.4 in 87% of the patients for near vision, and 56% for distant vision. The patients had complained that they could not read books, see a blackboard, recognize a person at a distance, and had other problems because of low vision. However, with the use of low vision aids their satisfaction with their vision rose to 70%. Hand magnifiers, high-powered spectacle lenses, and stand magnifiers were the low vision aids commonly used by people for near vision, while the Galilean telescope and Keplerian telescope were the most popular devices used for distant vision. In conclusion, low vision aids are very helpful devices to patients with low vision.
Adolescent↗
Effect of telescopic spectacles on head stability in normal and low vision.
Telescopic spectacles, highly magnifying visual aids mounted in spectacle frames, markedly alter the visual consequences of head movements. To evaluate the effect of this altered visual feedback on head stability, angular head velocity of normally sighted and low vision subjects was measured in the roll, pitch, and yaw axes. Measurements were made under two postural conditions: (1) quiet standing; and (2) walking in place, as well as three visual conditions: (1) eyes closed; (2) unmagnified vision; and (3) vision with 4 x binocular telescopic spectacles. For normal subjects during quiet standing, both unmagnified vision and vision with telescopic spectacles tended to reduce spontaneous head velocity in all axes as compared to the eyes-closed condition. However, in low vision subjects neither unmagnified vision nor vision with telescopic spectacles produced significant changes in values of head velocity relative to those measured with eyes closed. Spontaneous head velocities for standing low vision subjects tended to be higher than in normal subjects, although not all differences were statistically significant. During walking in place, Fourier analysis demonstrated prominent frequency components related to harmonics of the walking frequency under all viewing conditions. In normal subjects, vision with telescopic spectacles, to a greater degree than unmagnified vision, reduced head velocity during walking in the roll and yaw, but not the pitch, axes. For low vision subjects, significant reductions in head velocity during walking were observed only during vision with telescopic spectacles. These findings indicate that vision reduces angular instability of the head during standing and walking. Magnification produced by telescopic spectacles further improves head stability under some conditions, although the effect of vision is least evident in the pitch axis. The stabilizing effect of vision is reduced in low vision subjects.
Adult↗
Evaluation of the Vision Theophylline assays in the emergency department setting.
STUDY OBJECTIVES: To determine whether the use of fingerstick blood samples or venipuncture blood samples affect the accuracy and the precision of the Vision Theophylline I assay and the Vision Theophylline II assay in the emergency department setting. DESIGN: Prospective clinical trial. SETTING: ED in a university teaching hospital. SUBJECTS/INTERVENTIONS: Simultaneous fingerstick and venipuncture blood samples were obtained from adult patients who required baseline theophylline levels in the ED. MEASUREMENTS: The Vision system was used in the ED to measure theophylline concentrations from fingerstick and venipuncture samples. Vision samples were drawn and analyzed by one of three pharmacists rounding within the ED between March and October 1990. These pharmacists were instructed by laboratory personnel concerning pertinent operating procedures. The vision Theophylline I and Theophylline II assays are enzyme-inhibitor immunoassays contained within a multi-chamber test packet. The high-performance liquid chromatography (HPLC) theophylline assay was used as the reference method. MAIN RESULTS: Linear regression of theophylline concentrations determined by the Vision Theophylline I assay versus HPLC revealed a significant correlation for fingerstick samples (r = .9440; P less than .05) and for venipuncture samples (r = .9750; P less than .05). The accuracy values for Vision Theophylline I assay venipuncture and fingerstick samples versus HPLC were -0.63 +/- 1.2 mg/l and 0.22 +/- 1.8 mg/L, respectively. The precision for Vision Theophylline I assay venipuncture and fingerstick samples versus HPLC were 0.27 and 0.38, respectively. Linear regression of theophylline concentrations determined by the Vision Theophylline II assay versus HPLC revealed a significant correlation for fingerstick samples (r = .9804; P less than .05) and for venipuncture samples (r = .9875; P less than .05). Accuracy values for Vision Theophylline II fingerstick and venipuncture samples versus HPLC were -0.53 +/- 1.4 mg/L and -0.65 +/- 1.3 mg/L, respectively. Precision values for Vision Theophylline II fingerstick and venipuncture samples versus HPLC were 0.34 and 0.29, respectively. CONCLUSION: There is a strong correlation between theophylline concentrations measured by Vision Theophylline assay versus HPLC, regardless of whether the Vision Theophylline assay is performed on a fingerstick or venipuncture sample. Vision fingerstick samples were more accurate than Vision venipuncture samples for both Vision Theophylline I and II assays. Theophylline concentrations measured by the Vision system using venipuncture samples were slightly more precise than those using fingerstick samples when compared with HPLC analysis. These differences in accuracy and precision were not clinically relevant.
Blood Specimen Collection↗
Vision-related quality of life in patients with bilateral severe age-related macular degeneration.
PURPOSE: To determine the quality of life (QOL) of patients with bilateral severe age-related macular degeneration (AMD) before macular translocation with 360 degrees peripheral retinectomy. DESIGN: Prospective, consecutive, noncomparative case series. METHODS: An observational study assessed vision-related and general health QOL using the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) and the Medical Outcomes Study 12-item short form (SF-12) surveys, respectively. Mean QOL scores were correlated with patient age, duration of vision loss, and visual function. Mean QOL scores in study patients were compared with mean QOL scores in groups of patients with low vision, patients with AMD of varying severity, and reference populations. MAIN OUTCOME MEASURES: National Eye Institute VFQ-25 and SF-12 QOL scores. RESULTS: Seventy patients with a mean age of 76.4 years were studied. Mean distance visual acuity (VA) was 62.4 (Early Treatment Diabetic Retinopathy Study letters), mean near VA was 0.81 (logarithm of the minimum angle of resolution), and mean reading speed was 74.9 words per minute. Important NEI VFQ-25 quality of vision subscales (general vision, difficulty with distance tasks, difficulty with near tasks) and vision-specific subscales (dependency, role difficulties, mental health, social function limitations) tended to correlate negatively with increasing patient age and duration of vision loss, but correlated positively with better VA and reading speed. The mean QOL scores for these important quality of vision and vision-specific subscales were significantly worse than or similar to mean scores in patients with low vision, and significantly worse than scores in patients with AMD of varying severity and a reference population. The mean SF-12 physical composite score in study patients was similar to that seen in patients with AMD of varying severity, but significantly higher than that in patients with low vision and a reference population. The SF-12 mental composite score in study patients was similar to those of all 3 comparison groups. CONCLUSIONS: Patients with bilateral severe AMD have vision-related QOL similar to that of patients with low vision but significantly worse than those of patients with AMD of varying severity and persons without eye disease. This inability to perform vision-related daily tasks is not related to general health problems.
Aged↗
Referral to low vision services by ophthalmologists.
PURPOSE: People in need of low vision rehabilitation services often experience delays in referral to services. This study investigates referral criteria of Australian ophthalmologists, the frequency of referral of their patients with low vision and their perceptions of low vision services. METHODS: A survey was sent to a representative, random sample of 200 ophthalmologists. They were asked about criteria used for the referral of their patients with low vision. The survey included questions on the frequency with which they prescribed low vision devices (LVD) and referral of their patients to low vision and rehabilitation services and peer support groups. Perceptions of the quality and availability of low vision services were also investigated. RESULTS: The response rate was 82%. Approximately 11% of ophthalmologists' patients have low vision. It is uncommon for ophthalmologists to prescribe LVD but 67% refer most of their patients with low vision. It is less common for them to refer to rehabilitation services (29%) or peer support services (18%). The perceived local availability of services influences the rate of referral. Ophthalmologists who used the criteria of moderate low vision (< 6/21 to < 6/60) are more likely to refer more of their patients than those who use the criteria of severe low vision. CONCLUSIONS: Australian ophthalmologists refer most of their visually impaired patients to low vision services, but infrequently to rehabilitation services or peer support groups. Differences in perceived need for low vision services indicated by the criteria used for referral, and the perceived availability, influence the rate at which ophthalmologists refer their patients for services. Ophthalmologists are encouraged to refer patients with permanent visual loss to low vision services earlier.
Australia↗
Perceived barriers to the provision of low vision services among ophthalmologists in India.
PURPOSE: To identify and report the perceived barriers to the provision of low vision services among ophthalmologists in India. METHODS: Seventy nine ophthalmologists responded to a structured self-administered questionnaire. Information was collected to understand the level of awareness and barriers/constraints to provision of low vision services. Significant factors associated with each barrier/constraint and perceptions on providing low vision care were investigated. RESULTS: Lack of training/knowledge [65 (82.3%)], lack of awareness [59 (74.7%)] and non-availability of low vision devices [57 (72.2%)] were perceived as the major constraints / barriers to providing low vision care. At least one significant factor was found for each of the above constraints/barriers in providing low vision care. The perception of lack of awareness as being one of the constraints/barriers was significantly higher [OR 3.97 (95% CI, 1.02 - 7.8)] among ophthalmologists from organisations providing low vision services. The perception of lack of motivation as constraint/barrier was significantly higher [OR 3.62 (95% CI, 1.3 - 10.3)] among ophthalmologists from organisations providing low vision services and/or those involved in VISION 2020: The Right to Sight programmes [OR 3.83 (95% CI, 1.4 - 10.4)]. The likelihood of responding that low vision care is time consuming was greater for those belonging to a teaching institute [OR 7.19 (95% CI, 2.0 - 26.1)], those involved in low vision services [OR 5.45 (95% CI, 1.8 - 16.5)] and those who knew that low vision is a priority in VISION 2020 [OR 15.1, 95% CI, 1.5 -155.4]. CONCLUSION: Ophthalmologists need more education about the benefits of low vision care in order to increase their level of awareness and knowledge.
Health Knowledge, Attitudes, Practice↗
Management of functional vision loss.
BACKGROUND: Functional vision loss is a general term used to describe vision loss not associated with organic disease. Such cases are major challenges to the practitioner and demand a special workup. METHODS: Patients may manifest symptoms in typical ways that should alert the examiner to the possibility of functional vision loss. In addition, a variety of techniques help distinguish functional from organic causes of vision loss. These techniques include standard tests that yield characteristic findings in functional vision loss, as well as problem-specific procedures that have the specific aim of detecting functional vision loss. Techniques are described according to whether they are useful in monocular or binocular vision loss and in cases of moderate or severe vision loss. RESULTS: Three cases that illustrate the use of standard and select techniques to detect functional vision loss are presented. Differential diagnosis of functional from organic vision loss and special considerations in the management of patients with functional vision loss are also discussed. CONCLUSIONS: Although it is necessary to rule out underlying pathology in all cases of vision loss, a variety of techniques can provide positive evidence of functional vision loss.
Adult↗
Assessment of the impact of vision impairment.
PURPOSE: To describe the psychometric characteristics of the Impact of Vision Impairment (IVI) Profile and evaluate its validity and reliability over time and between different forms of administration. METHODS: The IVI is a 32-item questionnaire developed to measure the impact of vision impairment on restriction of participation in daily activities in five domains of functioning. Each item is rated on a six-level scale from "no difficulty" to "can't do because of vision." The IVI was administered by trained interviewers to 115 people with impaired vision (visual acuity less than 6/12 or visual field deficit) who attended the Royal Victorian Eye and Ear Hospital, a vision rehabilitation agency, or a self-help group for people with impaired vision. Data were also collected on demographic characteristics of participants, cause of vision impairment, and distance and near vision. General health status was assessed with the Short Form-12 (SF-12) of the Physical and Mental Health Summary Scales. A subset of participants completed the IVI twice, either 1 to 2 weeks apart or by different forms of administration (different interviewers or self). RESULTS: Internal consistency of total and domain average IVI scores was high (alpha = 0.80-0.96) and sequential elimination of items did not affect consistency. Total and domain average IVI scores correlated moderately with both near and distance vision (r = 0.21-0.31) but did not correlate with physical or general health or comorbidity. Total and domain average IVI scores correlated most closely with global measures of restriction of participation (r = 0.44-0.82). Principal-components analysis confirmed that all IVI items contribute to one underlying theme and tended to confirm two of the five domains: emotional reaction to vision loss and mobility. The first three components explained 43%, 8%, and 6% of the variation in the data. Guttman split-half reliability coefficients between different forms of administration and over time ranged from 0.73 to 0.94 for domain and total IVI scores. Mean absolute difference for domain and total scores between administrations was less than 1 step for all domains and the total score. CONCLUSIONS: This study provides support that the IVI has sufficient internal and construct validity to measure the effect of vision impairment on restriction of participation in daily activities. The IVI demonstrates acceptable reliability over a short period and yields consistent results between interviewers. The IVI can also be self-administered with assurance that the results will be comparable to those that would have been obtained by a trained interviewer. Therefore, the psychometric characteristics of the IVI support its use in assessment of the vision rehabilitation needs of people with impaired vision. Its stability over time indicates that it has potential to evaluate outcomes of intervention.
Activities of Daily Living↗
Major review: The underutilization of vision screening (for amblyopia, optical anomalies and strabismus) among preschool age children.
BACKGROUND: Nearly 80% of preschool age children never get an eye examination (1). Many "back to school" physical exams do not test for common vision disorders. Untreated eye and vision problems can interfere with most life experiences. The prevalence of undetected vision problems among preschool age children is estimated to be 5% to 10% (2). Failure to detect visual impairment early may have a permanent effect on long term vision outcomes, education achievement, and self esteem (3). The most common vision disorders among children are strabismus, amblyopia and optical problems impairing visual acuity and depth perception. Various professional organizations, including the American Academy of Pediatrics (AAP), advise preschool vision screening to detect and correct vision problems before school entry. The AAP also recommends that children continue to receive periodic eye and vision examinations throughout childhood. However, resources for this level of care are rarely available. As such, only 21% of preschool age children receive vision screening and even fewer children get a comprehensive eye examination (1). PURPOSE: The purpose of this review is to determine, through a critical review of the literature, the social, economic, and political barriers which contribute to the underutilization of vision screening among preschool age children. A secondary aim is to identify gaps in the literature base that may be needed to complete a public policy response to this problem. METHOD: A comprehensive review and analysis of the pertinent available literature. RESULTS: A variety of barriers exist which prevent children from receiving proper vision screening. They include social, economic and even political problems. Social contextual barriers include ignorance, inconvenience, language, and a lack of providers. Financial barriers affect low income families. Political barriers reside in the disproportionately meager funding of preventative medicine. Moreover there are additional factors which put preventative medicine for vision at a disadvantage compared to other pediatric demands like immunizations, such as the danger to both the individual and society from the medical condition being prevented. CONCLUSION: Even considering large gaps in the literature concerning this topic, it is clear that low income, minority, uninsured families are at high risk of not utilizing vision screening. Ignorance remains a major problem at all levels so improvements in the distribution of information and education are needed and should yield improvement. Additional funding is necessary to pay for these remedies. Titration and direction of available resources to those at highest risk will create the greatest return on such efforts.
Amblyopia↗
Racial variations in causes of vision loss in nursing homes: The Salisbury Eye Evaluation in Nursing Home Groups (SEEING) Study.
OBJECTIVE: To determine the prevalence and causes of low vision in a large sample of nursing home residents. METHODS: Twenty-eight nursing homes on the Eastern Shore of Maryland and Delaware were enrolled in a clinical trial to assess the impact of vision restoration/rehabilitation on nursing home residents. Visual acuity was measured using both recognition charts and preferential looking techniques. An ophthalmologist examined all residents with visual acuity worse than 20/40 in the better-seeing eye and determined the primary cause for decreased vision. Results are reported for the better-seeing eye. RESULTS: Of 2544 eligible residents, 1591 (63%) participated, but 286 residents were unable to respond to visual acuity testing. Of the remaining 1307 residents, 496 (37%) had best-corrected visual acuity worse than 20/40 in the better-seeing eye. Causes were ascribed for 412 subjects. Rates of low vision were similar between African American subjects and white subjects (39% and 38%, respectively; age-adjusted P =.18). Cataract was the leading cause of low vision, responsible for 37% of low vision among white subjects and 54% of low vision among African American subjects. Macular degeneration was responsible for 29% of low vision among white subjects but only 7% among African American subjects. Glaucoma caused low vision in 4% of white subjects and 10% of African American subjects. Refractive error was not a frequent cause of low vision in nursing home residents. CONCLUSIONS: Low vision is highly prevalent among nursing home residents, with 37% having visual acuity worse than 20/40 in the better-seeing eye. Differences in causes of low vision between African American subjects and white subjects were noted, with African American subjects more likely to have vision loss on the basis of cataract, a readily treated condition. Appropriate interventions for nursing home residents, who face significant obstacles in accessing eye care services, have the potential to improve the quality of life of this at-risk older population.
Aged↗
Contribution of central and peripheral vision to the regulation of stance: developmental aspects.
Postural oscillations in 6-, 8-, and 10-year-old children were analyzed in four conditions of vision of the environment (complete vision, peripheral vision, central vision and no-vision) and two conditions of ankle somatosensory information (normal and altered support surfaces with a 5-cm-thick foam). Children were more stable with than without vision. This was observed whether children had complete or partial vision (central or peripheral). They were also more stable with the normal than with the altered support surface. Overall, there was no effect of age. Beyond these well-established results, the present experiment showed the complementary role of peripheral and central vision in the regulation of children's posture. For the 6- and 10-year-olds, central and peripheral vision yielded similar postural stability, whereas for the 8-year-olds, central vision yielded greater postural stability than peripheral vision. The analysis of postural oscillations in the medio-lateral and antero-posterior planes showed that, for the three age groups, central vision was as efficient whatever the plane. On the other hand, after age 6, peripheral vision was more efficient for regulating antero-posterior than medio-lateral oscillations. The contribution of the different sensory systems and their interaction for stabilizing posture in children should be specifically interpreted with regard to the operating characteristics of each sensory system at each age.
Age Factors↗
Vision impairment in Liverpool: prevalence and morbidity.
A database related to the activities of the Liverpool vision assessment team was used to identify all children with vision impairment aged 0-16 years, resident in Liverpool, UK, on 1 April 1995. Prevalence rates were calculated for all children with vision impairment, and separately for two groups: those with uncomplicated vision impairment, and those with additional pathology. Visual tract pathologies were tabulated and compared. Associated handicapping conditions were defined and the extent of multiple disability was investigated for all vision impaired children, for very low birthweight children, and for those with cortical visual impairment. Of 199 children with vision impairment, 69 (35%) had uncomplicated impairment and 130 (65%) had additional and usually multiple pathology. There were 111 boys (56%); the excess of males was not statistically significant. Prevalence rates per 10,000 population were 18.1 for all vision impairment, 6.3 for uncomplicated vision impairment, and 11.8 for vision impairment complicated by additional pathology. Genetically determined disease accounted for over half the cases of uncomplicated vision impairment. Among the 130 children with additional pathology, cortical visual impairment was the commonest visual tract finding, affecting 64 (49%); 86% had learning difficulties; 53% had cerebral palsy. Multidisability (two or more disabling conditions in addition to vision impairment) affected half the entire childhood vision impairment population. These data should assist health and education authorities to determine the size of the vision impairment problem and how it relates to other disabilities in childhood, and can facilitate resource allocation and service planning.
Adolescent↗