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Occupational therapy interventions in low vision rehabilitation.

Low vision can significantly decrease a person's functional ability and independence. With the continuing rise in age of our population, the number of people with low vision will increase substantially. Restoring and maintaining their ability to function independently through the use of specific interventions is an intricate process that calls for the collaboration of various health care professionals. Occupational therapists (OTs) and occupational therapy assistants are essential members of the multidisciplinary rehabilitation team providing such interventions. OTs in low vision rehabilitation enhance performance for specific activities of daily living by training skills that are dependent on residual vision, such as reading and writing. OTs also conduct environmental assessments in the home and in the workplace or school to improve and promote a safe environment for patients with low vision. OTs may also assist in developing rehabilitation programs for orientation and mobility, driving, and vision rehabilitation therapy. To prepare for the future needs of the ageing Canadian population, more low vision rehabilitation practitioners and more funding for multidisciplinary rehabilitation programs are required.

Humans↗

Brief daily periods of unrestricted vision can prevent form-deprivation amblyopia.

PURPOSE: To characterize how the mechanisms that produce unilateral form-deprivation amblyopia integrate the effects of normal and abnormal vision over time, the effects of brief daily periods of unrestricted vision on the spatial vision losses produced by monocular form deprivation were investigated in infant monkeys. METHODS: Beginning at 3 weeks of age, unilateral form deprivation was initiated in 18 infant monkeys by securing a diffuser spectacle lens in front of one eye and a clear plano lens in front of the fellow eye. During the treatment period (18 weeks), three infants wore the diffusers continuously. For the other experimental infants, the diffusers were removed daily and replaced with clear, zero-powered lenses for 1 (n=5), 2 (n=6), or 4 (n=4) hours. Four infants reared with binocular zero-powered lenses and four normally reared monkeys provided control data. RESULTS: The degree of amblyopia varied significantly with the daily duration of unrestricted vision. Continuous form deprivation caused severe amblyopia. However, 1 hour of unrestricted vision reduced the degree of amblyopia by 65%, 2 hours reduced the deficits by 90%, and 4 hours preserved near-normal spatial contrast sensitivity. CONCLUSIONS: The severely amblyogenic effects of form deprivation in infant primates are substantially reduced by relatively short daily periods of unrestricted vision. The manner in which the mechanisms responsible for amblyopia integrate the effects of normal and abnormal vision over time promotes normal visual development and has important implications for the management of human infants with conditions that potentially cause amblyopia.

Amblyopia↗

The prevalence of blindness and low vision in older onset diabetes mellitus and associated factors: a community-based study.

PURPOSE: This community-based study was conducted to assess the prevalence and related factors of low vision and legal blindness in older onset diabetic patients (diagnosed at age 30 and older). METHODS: All known diabetic patients who live in the four primary health care center region Abidinpaşa Ankara, Turkey (total population: 96,348) were included in this cross-sectional study. The prevalence of known diabetes mellitus is 2.2%, of which 96.6% are older onset and 3.4% are younger onset. RESULTS: In the older onset diabetes group (1289 cases), 10.8% of the population had low vision and only 2.7% had legal blindness. Diabetic retinopathy (DR) was observed in 23.6% of the patients with low vision (42% proliferative DR) and in 62.9% of the patients with legal blindness (90.1 % proliferative DR). CONCLUSIONS: In older onset diabetic patients with low vision, nonproliferative retinopathy was a more frequent cause of impaired vision than proliferative retinopathy. Low vision and legal blindness caused by retinopathy were significantly associated with sex, age at examination, age at diagnosis, duration of diabetes, type of diabetes treatment, and hypertension in univariate analysis. However, in logistic regression analysis, low vision and legal blindness caused by retinopathy were found to be associated with longer duration of diabetes (> or =15 years), use of insulin, and hypertension.

Adult↗

Melatonin regulation in humans with color vision deficiencies.

Light can induce an acute suppression and/or circadian phase shift of plasma melatonin levels in subjects with normal color vision. It is not known whether this photic suppression requires an integrated response from all photoreceptors or from a specialized subset of photoreceptors. To determine whether normal cone photoreceptor systems are necessary for light-induced melatonin suppression, we tested whether color vision-dificient human subjects experience light-induced melatonin suppression. In 1 study, 14 red-green color vision-deficient subjects and 7 normal controls were exposed to a 90-min, 200-lux, white light stimulus from 0200-0330 h. Melatonin suppression was observed in the controls (t = -7.04; P < 0.001), all color vision-deficient subjects (t = -4.76; P < 0.001), protanopic observers (t = -6.23; P < 0.005), and deuteranopic observers (t = -3.48; P < 0.05), with no significant difference in the magnitude of suppression between groups. In a second study, 6 red/green color vision-deficient males and 6 controls were exposed to a broad band green light stimulus (120 nm with lambda max 507 nm; mean +/- SEM, 305 +/- 10 lux) or darkness from 0030-0100 h. Hourly melatonin profiles (2000-1000 h) were not significantly different in onset, offset, or duration between the two groups. Melatonin suppression was also observed after exposure to the green light source at 0100 h (color vision deficient: t = -2.3; df = 5; P < 0.05; controls: t = -3.61; df = 5; P < 0.01) and 0115 h (color vision deficient: t = -2.74; df = 5; P < 0.05; controls: t = -3.57; df = 5; P < 0.01). These findings suggest that a normal trichromatic visual system is not necessary for light-mediated neuroendocrine regulation.

Adult↗

Pseudotumor cerebri: CT findings and correlation with vision loss.

OBJECTIVE: The purpose of this study was to determine if orbital and cerebral CT can be used to distinguish normal patients from those with pseudotumor cerebri, and to correlate CT findings with the severity of visual impairment. SUBJECTS AND METHODS: Seventeen patients with a clinical diagnosis of pseudotumor cerebri were compared with 20 age- and sex-matched control subjects. Thin-section coronal and axial CT scans of the orbit and whole-brain axial CT scans were available for all subjects. The diameter of the optic nerve sheath, the degree of reversal of the optic nerve head, the presence and degree of empty sellae, and ventricular and sulcal sizes were evaluated without knowledge of whether or not the subject had pseudotumor cerebri. The same parameters were compared for two subgroups of patients with pseudotumor cerebri: those with mild vision loss and those with severe vision loss. RESULTS: Patients with pseudotumor cerebri had significantly larger optic nerve sheaths than did control subjects (6.5 +/- 0.83 mm vs 5.4 +/- 0.69 mm). Radiologic evidence of papilledema with reversal of the optic nerve head was found in 12 of 17 patients compared with one of 20 control subjects. An empty sella was seen more frequently and to a greater degree in patients with pseudotumor cerebri than in control subjects (16 vs seven). Eight of nine patients with severe vision loss and four of eight patients with mild to moderate vision loss had reversal of the optic nerve head; the degree was greater in the group with severe vision loss. No difference in ventricular size or sulcal enlargement was seen between any of the groups. The opening CSF pressures of the two groups with vision loss were not significantly different (348 +/- 80 mm H2O vs 391 +/- 98 mm H2O). CONCLUSION: In addition to the role of CT in excluding intracranial disease as a basis for the clinical syndrome of pseudotumor cerebri, thin-section CT of the orbits reveals a constellation of findings, including enlarged optic nerve sheaths, reversal of the optic nerve head, and empty sellae in patients with pseudotumor cerebri. Furthermore, severe vision loss in these patients correlates with more frequent and more severe reversal of the optic nerve head.

Adolescent↗

[Inherited colour vision deficiencies--from Dalton to molecular genetics].

In recent years, great advances have been made in our understanding of the molecular basis of colour vision defects, as well as of the patterns of genetic variation in individuals with normal colour vision. Molecular genetic analyses have explained the diversity of types and degrees of severity in colour vision anomalies, their frequencies, pronounced individual variations in test results, etc. New techniques have even enabled the determination of John Dalton's real colour vision defect, 150 years after his death. Inherited colour vision deficiencies most often result from the mutations of genes that encode cone opsins. Cone opsin genes are linked to chromosomes 7 (the S or "blue" gene) and X (the L or "red" gene and the M or "green" gene). The L and M genes are located on the q arm of the X chromosome in a head-to-tail array, composed of 2 to 6 (typically 3) genes--a single L is followed by one or more M genes. Only the first two genes of the array are expressed and contribute to the colour vision phenotype. The high degree of homology (96%) between the L and M genes predisposes them to unequal recombination, leading to gene deletion or the formation of hybrid genes (comprising portions of both the L and M genes), explaining the majority of the common red-green colour vision deficiencies. The severity of any deficiency is influenced by the difference in spectral sensitivity between the opsins encoded by the first two genes of the array. A rare defect, S monochromacy, is caused either by the deletion of the regulatory region of the array or by mutations that inactivate the L and M genes. Most recent research concerns the molecular basis of complete achromatopsia, a rare disorder that involves the complete loss of all cone function. This is not caused by mutations in opsin genes, but in other genes that encode cone-specific proteins, e.g. channel proteins and transducin.

Color Vision Defects↗

A retrospective study of low-vision cases in an Indian tertiary eye-care hospital.

PURPOSE: To obtain data on the characteristics of low-vision patients seen at a tertiary eye care hospital in India. METHODS: Records of 410 patients were retrospectively reviewed at the Centre for Sight Enhancement, L.V. Prasad Eye Institute, Hyderabad, India. Patient underwent a comprehensive clinical low-vision examination. Data obtained included age, gender, consanguinity, visual acuity, visual fields, ocular conditions causing low vision and types of low-vision devices and methods prescribed. RESULTS: Two hundred and ninety seven (72%) of 450 patients were male. One-fifth were in the 11-20 years age group (21%). Visual acuity in the better eye was < 6/18-6/60 in almost half these patients (49.3%). One hundred and twenty two patients (29.9%) referred with a visual acuity of > or = 6/18, either had difficulty in reading normal print or had restricted visual fields. The main causes for low vision were: retinitis pigmentosa (19%), diabetic retinopathy (13%), Macular diseases (17.7%), and degenerative myopia (9%). Visual rehabilitation was achieved using accurate correction of ametropia (174 patients), approach magnification (74 patients) and telescopes (45 patients) for recognising faces, watching television and board work. Spectacle magnifiers (187 patients), hand/stand magnifiers (9 patients), closed-circuit television (3 patients), overhead illumination lamp (143 patients) and reading stand (24 patients) were prescribed for reading tasks. Light control devices (146 patients) were used for glare control, and cane (128 patients) and flashlight (50 patients) for mobility. Patients were trained in activities to improve their daily living skills, (54 patients); counselled in environmental modification (144 patients) and ancillary care (63 patients) for educational and vocational needs. CONCLUSION: Data obtained from this study elucidates the characteristics of low-vision patients. This information is likely to help in the development of appropriate low vision services.

Adolescent↗

Color vision in 42 Congolese patients with tuberculosis receiving ethambutol treatment.

PURPOSE: To study color vision in Congolese patients with tuberculosis receiving ethambutol therapy. METHODS: A prospective, descriptive study of color vision test in patients with systemic tuberculosis receiving ethambutol was performed between April 1995 and January 1998 at the Department of Ophthalmology, University of Kinshasa. Color vision tests were assessed with pseudoisochromatic plates (the Ishihara Pseudo-isochromatic Plates), the AO-HRR (American Optical Handy Rand Rittler), the Bölle and Kastel anomaloscope, Farnsworth-Munsell test (the D-15 and the FM-100). RESULTS: There were 42 patients with a mean age of 33 years (range, 14 to 75 years). The color vision of all the patients was found to be normal as measured by the Ishihara pseudoisochromatic plates. One (2%) patient showed color vision defect (anarchic axis] with the OA-HRR test. Three (7%) of 42 patients displayed blue-yellow color axis or anarchic axis color vision test on the D-15 test. Fifteen (36%) of 42 patients had high total error scores at the Farnsworth-Munsell 100 test. The color axis was as follows: anarchic axis (13.1%), red-green-color and blue-yellow-color combined axis (13.1%), blue-yellow color axis (7.5%). Results of the Bölle and Kastel anomaloscope were normal in all patients. CONCLUSION: Our results confirm the importance of color vision examinations in the detection of the complications of ethambutol treatment.

Adolescent↗

Genotype-phenotype relationships in human red/green color-vision defects: molecular and psychophysical studies.

The relationship between the molecular structure of the X-linked red and green visual pigment genes and color-vision phenotype as ascertained by anomaloscopy was studied in 64 color-defective males. The great majority of red-green defects were associated with either the deletion of the green-pigment gene or the formation of 5' red-green hybrid genes or 5' green-red hybrid genes. A rapid PCR-based method allowed detection of hybrid genes, including those undetectable by Southern blot analysis, as well as more precise localization of the fusion points in hybrid genes. Protan color-vision defects appeared always associated with 5' red-green hybrid genes. Carriers of single red-green hybrid genes with fusion in introns 1-4 were protanopes. However, carriers of hybrid genes with red-green fusions in introns 2, 3, or 4 in the presence of additional normal green genes manifested as either protanopes or protanomalous trichromats, with the majority being protanomalous. Deutan defects were associated with green-pigment gene deletions, with 5' green-red hybrid genes, or, rarely, with 5' green-red-green hybrid genes. Complete green-pigment gene deletions or green-red fusions in intron 1 were usually associated with deuteranopia, although we unexpectedly found three carriers of a single red-pigment gene without any green-pigment genes to be deuteranomalous trichromats. All but one of the other deuteranomalous subjects had green-red hybrid genes with intron 1, 2, 3, or 4 fusions, as well as several normal green-pigment genes. The one exception had a grossly normal gene array, presumably with a more subtle mutation. Amino acid differences in exon 5 largely determine whether a hybrid gene will be more redlike or more greenlike in phenotype. Various discrepancies as to severity (dichromacy or trichromacy) remain unexplained but may arise because of variability of expression, postreceptoral variation, or both. When phenotypic color-vision defects exist, the kind of defect (protan or deutan) can be predicted by molecular analysis. Red-green hybrid genes are probably always associated with protan color-vision defects, while the presence of green-red hybrid genes may not always manifest phenotypically with color-vision defects. Four subjects who were found to have 5' green-red hybrid genes in addition to normal red- and green-pigment genes had normal color vision as determined by anomaloscopy. These were discovered among a group of 129 Caucasian males who had been recruited as volunteers for a vision study.(ABSTRACT TRUNCATED AT 400 WORDS)

Base Sequence↗

Is colour vision impairment associated with cognitive impairment in solvent exposed workers?

AIMS: To determine whether acquired colour vision deficits in solvent exposed individuals are associated with cognitive impairment. METHODS: A sample of 82 painters and 38 other subjects were studied. Alcohol, drug, and smoking histories were obtained. Colour vision was tested using the Lanthony D-15-d colour vision test. Cognitive impairment was measured using the Benton visual retention test, Trail making A, and Trail making B tests. Pre-morbid IQ was estimated using the National Adult Reading Test. Solvent exposure in all subjects was estimated using a previously validated, structured subjective assessment methodology. RESULTS: After exclusion of subjects with competing causes of colour vision impairment the final group of men numbered 78. There was a significant association on multiple linear regression between the mean colour confusion index (CCI) and three measures of cognitive impairment, the Benton visual retention test, Trail making A, and Trail making B tests after adjusting for the effects of age (or IQ as appropriate), alcohol, and smoking. CONCLUSION: Acquired colour vision loss is associated with cognitive impairment in solvent exposed workers. However, given the prevalence of acquired colour vision losses in the adult population, colour vision testing is unlikely to be of value as a screening test.

Adult↗

[A cross-sectional survey of blindness and low vision among adults aged 60 years and above in Xinchengqiao Blocks, Nantong].

OBJECTIVE: To investigate the prevalence and causes of blindness and low vision among adults aged > or = 60 years in the urban population of Nantong. METHODS: Cluster sampling was used to select 8 from 14 communities in Xinchengqiao Blocks, in which all individuals aged > or = 60 years were visited. The visual acuity without correction and the presenting acuity with the participants' habitual distance correction were measured separately for each eye. In individuals with visual acuity less than 0.6, pinhole visual acuity was tested with pinhole spectacle. External eye, anterior segment and ocular fundus were examined by the ophthalmologist using a slit lamp-microscope and direct ophthalmoscopy. The survey was preceded by a pilot study. RESULTS: Of 3352 enumerated subjects, 3040 individuals participated in this survey (90.69% response rate). According to pinhole visual acuity and World Health Organization (WHO) visual impairment criterion (blindness: less than 0.05 in the better eye; low vision: less than 0.3 to 0.05 in the better eye), the prevalence of blindness and low vision was 1.35% and 1.84% respectively. The prevalence of blindness and low vision for females were 1.92% and 2.33%, respectively, which were differenced from that in males (0.66% and 1.24%, respectively). The prevalence of blindness and low vision increased with age. The survey showed that the most important cause leading to blindness and low vision was cataract. According to the presenting visual acuity and visual impairment criterion (blindness: less than 0.1 in both eyes), the prevalence of blindness and visual impairment was 1.58% and 13.59%, respectively, 2.10% and 15.98% in females and 0.95% and 10.66% in males, respectively. The prevalence of blindness and visual impairment was raised with increasing age. Cataract was also the leading cause for blindness. CONCLUSIONS: The prevalence of blindness in the Nantong area was lower than that in northern, southern and western China. Females and illiteracy were more likely to have blindness and low vision than that of males and literate. The leading causes of blindness in Nantong are, in descending sequence, cataract, ocular fundus diseases, ametropia and corneal scar/opacity.

Aged↗

[Color vision defects of macular diseases].

Patients with macular diseases such as x-linked juvenile retinoschisis, cone dystrophy, and age-related macular degeneration were studied regarding color vision defects. In 9 of 15 eyes of patients with x-linked juvenile retinoschisis, blue-yellow defects were demonstrated. In the older patients with this dystrophy, color vision defects were more severe than in younger ones. Fluorescein angiography revealed retinal pigment epithelium (RPE) atrophy at the macular area in these older patients. Therefore, it was suggested that the color vision defects were due to dysfunction of the outer sensory retina, occurring secondarily to the inner sensory retina. In patients with cone dystrophy, all the examined eyes showed severe color vision defects. It was proved that the size of the atrophic lesion which when ophthalmoscopically evaluated was found to have some relationship with the degree of color vision defects. In patients with age-related macular degeneration, most of the examined eyes showed color vision defects. Moreover eyes with soft drusen formation and/or RPE detachment usually showed more severe color vision defects than the eyes with hard drusen formation and/or RPE atrophy.

Adolescent↗

Foveal vision function before and after fluorescein angiography.

PURPOSE: Fluorescein angiography is routinely used in ophthalmologic practice with minimal changes in vision reported by the patient after the procedure. Recent animal work has suggested that fluorescein may be cytotoxic in the presence of light and may cause retinal damage. The authors examined whether any changes occur in foveal vision function after fluorescein angiography. METHODS: A battery of tests of vision function--including visual acuity, contrast sensitivity, color vision, and two-color increment thresholds designed to isolate individual cone pathways--was administered before and 48 hours after fluorescein angiography to a group of 10 patients with good visual acuity. RESULTS: Most of the patients showed significant abnormalities with the nonstandard tests; however, no significant changes in central vision function were found 48 hours after fluorescein angiography. CONCLUSION: Even sensitive vision tests show no measurable effect of fluorescein angiography on foveal vision function in eyes with significant disease.

Adult↗

Meeting the vision care needs of aircraft pilots.

BACKGROUND: Of the approximately 640,000 currently active civilian aircraft pilots in the United States, many receive their vision care from optometrists. This report reviews the vision requirements for pilots and describes the results of surveys designed to determine whether the vision care needs of pilots are being fully met by optometrists. METHODS: Surveys were sent to 100 optometrists and 120 pilots in the Seattle, Washington area. The optometrists' surveys included questions regarding knowledge of licensing regulations and differences in examinations for pilots and nonpilots. The pilots' surveys asked about vision care examinations, experiences, and expectations. RESULTS: The majority of pilots recognized the need for complete vision examinations, beyond those provided as part of their flight physicals. Their most commonly reported needs were for evaluation of any medical problems, obtaining correct lens powers, sunglass tints, and for information on vision enhancement. Results of the survey also indicated that optometrists were relatively unfamiliar with Federal Aviation Administration (FAA) regulations and with the forms needed to report examination results to the FAA. CONCLUSIONS: Many of the optometrists surveyed knew little about FAA regulations, test procedures, or required eye examinations. By becoming more familiar with basic information regarding these regulations and the demands of aircraft operation, optometrists can enhance their ability to provide complete vision care services for their pilot patients.

Aerospace Medicine↗

[A 76-year-old man with loss of vision and dementia].

We report a 76-year-old man who developed blurred vision and dementia. He was apparently well until April 4, 1990 (70-year-old at that time) when he had a sudden onset of bilateral loss of vision. Corrected vision was 0.1 (right) and 0.09 (left). He was admitted to the ophthalmology service of our hospital on April 9, 1990, and neurological consultation was asked on April 11. Neurologic examination revealed alert and oriented man without dementia. Higher cerebral functions were intact. He had bilateral large visual field defects with loss of vision; he was only able to count the digit number with his right eye and to recognize hand movement with his left eye. Otherwise neurologic examination was unremarkable. General physical examination was also unremarkable; he had no hypertension. Cranial CT scan was normal on April 11; lumber spinal fluid contained 1 cell/microliter, 63 mg/dl of sugar, and 97 mg/dl of protein; myelin basic protein was detected, however, oligoclonal bands were absent. He was treated with methylprednisolone pulse therapy and oral steroid, however, no improvement was noted in his vision. He started to show gaze paresis to left, ideomotor apraxia, agnosia of the body, and dementia. Cranial CT scan on June 11 revealed a low density area in the deep left parietal white matter facing the trigonal area of the lateral ventricle. He was discharged on July 2, 1990. Hasegawa dementia scale was 2/32.5 upon discharge. In the subsequent course, he showed improvement in his mental capacity and Hasegawa dementia scale was 22.5/32.5 in 1991, however, no improvement was noted in his vision. In 1994, he started to show mental decline in that he became disoriented, and showed delusional ideation of self persecution and depersonalization with occasional confusional state. He also showed unsteady gait. Cranial MRI on February 13, 1996 revealed a T2-high signal intensity lesion on each side of the parietal deep white matter more on the left and another T2-high signal intensity lesion in the left pons as well as in the right thalamus. He complained of right hypochondrial pain and was admitted to another hospital on April 22, 1996. He was markedly confused and demented. He continued to show bilateral loss of vision, but no motor palsy was noted. Cranial CT scan on April 23, 1996 revealed diffuse cortical atrophy and ventricular dilatation in addition to the low density areas in both parietal deep white matter. He developed jaundice in the middle of May. Abdominal CT scan revealed multiple low-to iso-density areas in the liver and marked iso-to high-density swelling of the right kidney. The patient expired on June 9th, 1996. The patient was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had had a carcinomatous limbic encephalitis with optic neuropathy and a choleduct carcinoma. Other opinions entertained included acute disseminated encephalomyelitis with optic neuritis, and granulomatous angiitis of the central nervous system. Some participants thought the primary site of the carcinoma was the right kidney with metastasis to the liver. Post mortem examination revealed a mixed type carcinoma in the right kidney with liver metastases. Neuropathologic examination revealed an incomplete softening in the optic chiasm and the left optic nerve, and in the left parieto-occipital areas. (The right hemisphere was frozen for future biochemical assay.) One of the adjacent cortical arteries had an organized thrombus. Other arteries and arterioles also showed sclerotic changes. Some of the leptomeningeal arteries were positive for Congored staining as well as for beta-amyloid immunostaining. Many senile plaques were seen diffusely in the cerebral cortex and neurofibrillary tangles were seen in the CA1 area and the parahippocampal gylus. No cellular infiltrations or demyelinated foci were seen. The neuropathologic features were consistent with circulatory disturbance based on the amyloid angiopa

Aged↗

A survey of vision screening policy of preschool children in the United States.

A state-by-state survey regarding preschool vision screening guidelines, policies, and procedures was conducted. Currently 34 states provide vision screening guidelines and 15 states require vision screening of at least some of their preschool-aged children. The Department of Public Health administers the programs in 26 states, the Department of Education in 13. A wide range of professional and lay personnel conduct preschool vision screenings, and nurses participate in the screening process in 22 states. Visual acuity is assessed in 30 states, eye alignment in 24 states, refractive error in eight states, and color vision in 10 states. A combination of screening tests is recommended in 24 states. Currently, 45 states do not require screening of all preschool children. Thus, although laws, guidelines, and recommendations exist in most states, many preschool-age children do not have access to vision screening programs.

Child, Preschool↗

Vision care requirements among intellectually disabled adults: a residence-based pilot study.

Intellectually disabled adults have an high incidence of visual problems and they are often unable to communicate their visual difficulties. At Lennox Castle and Waverley Park Hospitals, vision care is through referral by medical and nursing staff to designated optometrists and ophthalmologists. This practice has provided a good service when visual difficulties are noticed. The vision care requirements of all residents had not been comprehensively assessed and a new interdisciplinary procedure developed at Waverley Park Hospital had drawn attention to the fact that only 11% had been offered vision assessment within the previous 5 years. In this study, 63 residents without specific referral received a comprehensive visual and medical assessment. The residents ranged from age 20 to 85 years and included the full range of disabilities. Objective assessments, ophthalmoscopy and retinoscopy were generally successful for all levels of disability. Visual acuity and visual fields were tested using methods suitable for nonverbal subjects. Success rates for these subjects were generally good, except in the profoundly disabled group where less than 30% were able to respond. A high prevalence of visual impairment, refractive error, squint and other ocular conditions was found. Visual impairment was most common in the severe and profoundly disabled groups because of optic nerve or cortical dysfunction. New spectacles were recommended for 23 residents (seven others had adequate correction). Nine residents were referred for ophthalmologic consultation, mainly for cataract. Three required monitoring for visual conditions. Thirty-one residents (49%) required no immediate action beyond documentation of the visual status. This study has shown a high prevalence of visual difficulties which were not previously detected. Routine biennial vision assessment of all residents is recommended to allow timely intervention to correct vision problems, and also to provide the necessary information about vision to plan appropriate programmes of activity.

Adult↗

Seeing into old age: vision function beyond acuity.

PURPOSE: To provide a comprehensive description of vision function beyond acuity in older individuals. METHODS: A sample of 900 individuals between the ages of 58 and 102 years (mean age of 75.5) was binocularly tested wearing habitual correction on a battery of psychophysical tests including high and low contrast acuity, low contrast low luminance acuity, disability glare, contrast sensitivity, color vision, stereoacuity, recovery from glare, and attentional visual fields. RESULTS: High contrast acuity is reasonably well maintained on average, even into very old ages. Spatial vision measures under conditions of reduced contrast or luminance, or glare reveal significant impairment in a large portion of the aged. Many older individuals also have greatly reduced stereopsis, poor color discrimination, and severely restricted peripheral fields under conditions of divided attention. A single exponential function relating performance to age fits all spatial vision data sets. The function for individual spatial measures lies at different positions along the age scale. The derived aging function with a time constant of approximately 15 years also fits results from other recent aging studies of acuity and contrast sensitivity. CONCLUSIONS: Standard visual acuity underestimates the degree of vision function loss suffered by many older individuals under the nonoptimal viewing conditions encountered in daily life. All spatial vision functions show a similar rate of decline with age of the population, but the age at which decline begins varies among measures.

Aged↗