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PubMedDate not supplied

Ocular findings in HIV-1 positive and HIV-1 negative participants in a rural population-based cohort in Uganda.

PURPOSE: To report the ocular findings in HIV-1 seropositive individuals and HIV-negative controls in a population-based cohort in rural Uganda. METHODS: Participants were examined by an ophthalmologist, who was unaware of their HIV-status. RESULTS: 238 participants were examined, 43 were HIV-1 prevalent cases (infected prior to 1990); 62 were HIV-1 incident cases and 133 were HIV-negative controls. Eleven of the HIV-positive participants had AIDS, and a further 8 had a CD4 count of less than 200 cells/mm3. Bilateral low vision was recorded in 9 participants and cataracts were the main cause of bilateral low vision. The mean intra-ocular pressure (IOP) was 12.6 mm Hg, and no association was found between IOP and CD4 lymphocyte count. Although significantly more HIV positives had some sign of intraocular inflammation compared to the negatives (p = 0.02) there was no significant linear trend in the HIV positives with decreasing CD4 count. Overall, 11 (26%) prevalent, 6 (10%) incident cases and 8 (6%) HIV-negatives controls had some evidence of intraocular inflammation, however, only one person had reduced visual acuity attributable to these lesions. Punctate epithelial erosions and keratic precipitates in the anterior chamber were seen significantly more frequently in HIV-positives compared to the HIV-negative controls. Cotton wool spots were not seen. CONCLUSIONS: A substantial proportion of HIV-infected persons had ocular findings which may have been attributable to their infection, however in only one case did this result in reduced visual acuity. Although the ocular complications of AIDS seem to comprise a large extra element in the work load of tertiary care hospitals dealing with eye problems, on a population basis such cases are infrequent.

Adult↗
PubMed2000

The calibration of a 2.5x Galilean focusable telescope as an optometer for refraction.

A 2.5x Selsi achromatic Galilean focusable telescope was calibrated for refraction at 6 m. In its calibration, minus power trial lens was placed at the objective of the telescope to simulate vergence of a target at a finite distance, before the back vertex power (BVP) of the telescope at each setting (telescope length) was measured by a focimeter. By using a graphical presentation of the results, the BVP of the telescope at each setting could be determined at different selected target distances. For a target vergence of -0.167 D or a distance of 6 m, the common testing distance in clinical practice, this calibrated telescope had a BVP or refraction measuring range of -7.27(-)+7.52 D. When this telescope was used to measure simulated manifest refractive errors at 6 m, it yielded a mean error of +0.13 D with a 95% confidence limit of agreement of -0.38(-)+0.64 D. These results indicated that the accuracy and precision of telescopic refraction were comparable to that of retinoscopy. Therefore, the calibrated telescope could be considered as a reliable and inexpensive instrument for determining spherical refractive errors. Telescopic refraction is applicable in refracting economically disadvantaged population in underserved areas where modern equipment and electricity are not available. In addition, it provides an alternative subjective refraction method for low vision population because the magnification of this calibrated telescope has the advantage of allowing low vision patients to be refracted at the common 6 m testing distance in clinical practice.

Adult↗
PubMed1999

Low uptake of eye services in rural India: a challenge for programs of blindness prevention.

OBJECTIVES: To investigate service uptake in a rural Indian population served by outreach eye camps and to identify barriers to uptake. PARTICIPANTS AND METHODS: A routine eye camp was conducted within 5 km of each of 48 randomly selected villages of typically Hindu, backward-caste communities. Subsequently, participatory rural appraisal-community mapping, focus groups, matrix ranking, and semistructured interviews-was undertaken to explore community views of eye problems. An eye examination was conducted on persons with eye problems who did not attend the eye camp. Predictors of attendance were identified by multilevel regression analysis. RESULTS: Of 749 adults with an eye problem, 51 (6.8%) attended the eye camp. Independent predictors of attendance were being male (odds ratio = 2.3; 95% confidence interval, 1.2-4.5) and living within 3 km of the camp (odds ratio = 4.5; 95% confidence interval, 1.7-12.5). Of the 552 persons who did not attend the eye camps and had an eye examination, 242 (43.8%) had low vision (visual acuity <6/18 to > or =3/60 in presenting better eye) and 38 (6.9%) were blind in both eyes. Cataract surgery was recommended for 197 (35.8%) of the persons who did not attend the eye camps. Of 109 persons with a previous cataract operation, 42 (38.5%) had low vision and 11 (10.1%) were blind. Fear (principally of eye damage), cost (direct and indirect), family responsibilities, ageism, fatalism, and an attitude of being able to cope (with low or no vision) were the principal barriers to attending the eye camps. CONCLUSIONS: A high proportion of people who could have benefited from eye treatment were not using available services. Poor visual outcomes were observed in surgically treated persons.

Attitude to Health↗
PubMed1981

Aging and low-contrast vision: face perception.

Previous work showed that despite good visual acuity, many healthy older people require more contrast to see gratings of low and intermediate spatial frequencies than do younger observers. Here we report that a daily perceptual activity, which relies on lower spatial frequency information, is also adversely affected: as compared to young individuals, many older individuals require more contrast to detect a face and to discriminate between two faces. Ocular pathology, optical changes within the eyeball, and variation in criterion are ruled out as explanations for the age-related elevation in threshold.

Adult↗
PubMed1995

Global data on blindness.

Globally, it is estimated that there are 38 million persons who are blind. Moreover, a further 110 million people have low vision and are at great risk of becoming blind. The main causes of blindness and low vision are cataract, trachoma, glaucoma, onchocerciasis, and xerophthalmia; however, insufficient data on blindness from causes such as diabetic retinopathy and age-related macular degeneration preclude specific estimations of their global prevalence. The age-specific prevalences of the major causes of blindness that are related to age indicate that the trend will be for an increase in such blindness over the decades to come, unless energetic efforts are made to tackle these problems. More data collected through standardized methodologies, using internationally accepted (ICD-10) definitions, are needed. Data on the incidence of blindness due to common causes would be useful for calculating future trends more precisely.

Blindness↗
PubMed2000

Binocular vision in older people with adventitious visual impairment: sometimes one eye is better than two.

PURPOSE: To determine the effect of adventitious visual impairment (low vision) on monocular and binocular spatial contrast sensitivity of older people. DESIGN: A between-within repeated measures design. PARTICIPANTS: Fifty-nine older adults between the ages of 50 and 96; 49 of the observers had age-related macular degeneration (AMD). MEASURES: Visual acuity screening and spatial contrast sensitivity. RESULTS: In almost half of the population with AMD, the sensitivity to spatial information, as measured by spatial contrast sensitivity, is worse when both eyes are used than when the stimuli are viewed with only one eye. This "binocular inhibition" is not related to the contrast sensitivity of the better eye or to acuities. Furthermore, this inhibition process is reflected primarily in images with medium to low spatial frequency components (medium to large size bars). CONCLUSIONS: These results have important implications for understanding the functional impact of low vision in older people. They suggest that almost one-half of older people with AMD view the world best using only one of their eyes, whereas for the other half, there is an advantage to using binocular vision for certain visual tasks.

Aged↗
PubMed2002

Relationship between vision impairment and ability to perform activities of daily living.

PURPOSE: To determine the relationship between clinical measures of vision impairment and the ability to perform activities of daily living (ADLs). METHODS: One hundred and twenty subjects with low vision from a variety of causes participated in the study. Vision impairment was assessed under binocular conditions by measuring distance visual acuity, near word acuity, Melbourne Edge Test contrast sensitivity, Pelli-Robson Chart contrast sensitivity and visual fields. The ADL performance was assessed using the Melbourne Low Vision ADL Index (MLVAI), which is in part an observed performance assessment of instrumental ADLs and in part a self-report assessment of basic self-care ADLs. RESULTS: All vision measures had a high, statistically significant correlation with MLVAI total score. Near word acuity, had the strongest correlation (r(s) = -0.86, p < 0.001), followed by Melbourne Edge Test contrast sensitivity (r(s) = 0.80, p < 0.001). Visual field had the weakest correlation (r(s) = 0.56, p < 0.001). Together, age, near word acuity, Melbourne Edge Test contrast sensitivity and visual field accounted for 82.2% (adjusted R2, p < 0.001) of the variance in MLVAI total score. All correlations obtained were higher for the observed performance assessment of instrumental ADLs than for the self-report assessment of basic self-care ADLs. CONCLUSIONS: Clinical vision impairment measures are highly correlated with capacity to perform ADLs, as measured by the MLVAI.

Activities of Daily Living↗
PubMed2005

[Prevalence study of age-related macular degeneration in Caojiadu blocks, Shanghai].

OBJECTIVE: To investigate the prevalence of age-related maculopathy (AMD) in Shanghai residents older than 50 years. METHODS: 1023 individuals were examined in the years 2002 and 2003 for clinical and subjective signs of dry and exudative AMD. A interview concerning clinical symptoms of AMD as also a complete eye exam was performed. Non-mydriatic retinoscopy was done by use of a direct opthalmoscopy. Fundus photography was used to confirm and document the diagnosis. The diagnosis of both forms of AMD was made according to the criteria of the Sub-society of Fundus Disease, Chinese Ophthalmological Society. RESULTS: 15.5% of the included population had AMD and 19 of them were exudative AMD. The prevalences of AMD in the age groups of 50-59, 60-69, 70-79 and more than 80 were identified as 5.7%, 13.5%, 20.2% and 23.5%, respectively (chi(2) = 27.97, P < 0.01). No statistical differences were found concerning atrophic and exudative AMD related to gender, education, daily focus time, smoking, alcohol consumption and systematic diseases. In the AMD patients, 5.1% and 36.2% of the eyes were identified as blind or with low vision. In exudative AMD patients, 23.3% and 63.3% of the eyes were identified as blind or with low vision. The visual acuity of eyes with exudative AMD was significantly lower than the visual acuity of atrophic AMD eyes. (chi(2) = 15.4, P < 0.01). CONCLUSIONS: The prevalence of AMD is high, and increasing with aging. The AMD, especially the exudative AMD, leads to severe visual impairment.

Age Factors↗
PubMed1999

Ocular changes in mucopolysaccharidosis IV A (Morquio A syndrome) and long-term results of perforating keratoplasty.

BACKGROUND: The mucopolysaccharidoses (MPS) are an inhomogeneous group of disorders of errors in the carbohydrate metabolism with severe ocular involvement (corneal opacification, retinal degeneration, optic atrophy). PATIENT PRESENTATION: We report on a boy aged 12 years, with Morquio A (MPS IV A) syndrome. Ocular findings: progressive pseudoexophthalmus due to shallow orbits, increasing corneal stromal clouding, intermittent dissociated manifest nystagmus of the left eye, nyctalopia. Visual acuity OD cc = 0.16, OS cc = 0.05. Electrophysiology: changes suggesting a symptomatic tapetoretinal degeneration and optic atrophy. TREATMENT AND COURSE OF DISEASE: OS: perforating keratoplasty. Postoperative improvement of visual acuity to 0.25 for nearly a year, followed by progressive reopacification of the corneal graft. Both eyes: progressive signs of tapetoretinal degeneration and optic atrophy. Visual acuity now reduced to OD 0.05, OS 0.1. CONCLUSIONS: Success of a keratoplasty is limited by (1) reopacification of the cornea, (2) visual impairment due to (a) retinal degeneration and (b) optic atrophy. The indication for perforating keratoplasty has to be thought about very carefully in these multimorbid patients. In our patient, beside progressive visual impairment there is a progressive deafness which dominates his social and school life. Attending school is severely complicated by the double handicap. Perforating keratoplasty enabled the boy to attend a school for physically handicapped without a special low-vision care for another year. Progressive visual loss without further treatment options now renders optical and electronic low-vision aids necessary. Although the time of improved visual acuity lasted less than a year, we think patients with a life expectancy of less than 20 years should have every possible improvement of their situation - even if it does not last permanently. We therefore propose perforating keratoplasty in spite of insufficient long-term results.

Child↗
PubMed1980

Natural history of vitreous hemorrhage in diabetic retinopathy.

Eighty-five eyes with severe vitreous hemorrhage on initial visit were followed for three to ten years without treatment. A comparison of initial and final visual acuities showed vision to have worsened in 36 eyes (42%), improved in 25 eyes (30%) and remained unchanged in 24 eyes (28%). Vision in 60 eyes was 5/200 or worse when last examined. Of 42 eyes followed three to six years (group 1), the low vision in 24 eyes (57%) was due to vitreous hemorrhage, while of 18 eyes that were followed seven to ten years (group 2), six (33%) had low vision due to vitreous hemorrhage. Traction detachments were found in five eyes (28%) in group 2 as compared with three (7%) in group 1. The prognosis for clearing of the hemorrhage was better when the fundus reflex was brighter and the retina adjacent to the ora serrata was visible. Clearing occurred sooner when the hemorrhage was retrohyaloid rather than in the vitreous gel. The study showed that ultimately 68% of the eyes had a visual acuity of 5/200 or worse.

Cataract↗
PubMed1982

Visual factors and orientation-mobility performance.

The ability of the person with low vision to achieve successful orientation and mobility depends on residual vision, age of onset of visual impairment, posture and balance, intelligence, body image, auditory-tactile abilities, and personality. This study assesses the role of the residual vision and looks in particular at visual fields, spatial contrast sensitivity, and visual acuity. Correlation coefficients indicate that, for low vision patients, spatial contrast sensitivity and visual fields each have more influence on orientation-mobility than does visual acuity.

Age Factors↗
PubMed1990

[Prevalence and causes of blindness in the Congo].

A population-based survey on the prevalence of blindness and eye disease has been conducted throughout the Congo. This was the first time such a survey had been carried out in a central African country with an equatorial climate. In comparison with data available from other African countries, the two rather unexpected characteristics resulting from the survey were lower blindness prevalence rates and the extremely rare cases of bilateral corneal scarring. In accordance with sampling procedures recommended by the WHO Programme for the Prevention of Blindness, 7041 people were selected and examined. The prevalence of blindness (visual acuity less than 3/60 in the better eye) was 0.3% (5700 people). The prevalence of low vision (visual acuity between 6/24 and 3/60 in the better eye) was 2.1% (40,000 people). The major causes of blindness and low vision were cataract (81% and 80%, respectively) and glaucoma (9% and 3.4%, respectively). A total of 22,000 people in the Congo require cataract surgery. Almost four-fifths of the current burden of blindness in this country is potentially curable through the provision of cataract surgery and aphakic glasses.

Aged↗
PubMed1995

The impact of age-related visual impairment on functional independence in the elderly.

Low vision is an extremely common problem in the elderly, which may have devastating consequences for functional independence and health status. It ranks only behind arthritis and heart disease as the etiology for impaired function in those over the age of 70. Macular degeneration is a leading cause of blindness and poor vision in the elderly. The central vision loss of this disorder can sometimes be postponed through laser therapy. Otherwise, the low visual state is best addressed with vision-enhancing devices, non-optical adaptive equipment, and patient education available through most occupational therapists. Referral to a low-vision rehabilitation program is sometimes needed for more comprehensive evaluation and intervention. Individual adaptation and supportive services often result in a significant improvement in function and quality of life for those elders with low vision.

Accidental Falls↗
PubMed2004

[Congenital achromatopsia: electroretinogram in early diagnosis].

PURPOSE: Achromatopsia is a hereditary disease responsible for congenital low vision. Patients present with nystagmus, abnormal visual behavior or photophobia. Only the electroretinogram (ERG) can confirm the diagnosis in infants. PATIENTS AND METHODS: Thirty children referred for nystagmus or low vision were included in this retrospective study. A complete ophthalmological examination, an ERG and when possible a color vision test (Ishihara, Farnsworth 15 Hue test) was done. A Ganzfeld ERG was performed in accordance with ISCEV standards in patients more than 6 years of age. In younger patients, a simplified method using electroluminescent diode stimulation was used and a comparative ERG in accordance with ISCEV standards was performed when the patients were old enough. RESULTS: The ERG response was identical in children and adults. It confirmed the diagnosis of achromatopsia: the scotopic components obtained in dark adapted conditions were normal, (scotopic a-wave, b2 wave). The photopic components, recorded in light-adapted conditions, in order to inhibit the scotopic response (photopic wave, b1 wave), were not recordable. The color vision tests confirmed color blindness; however, in some patients color denomination was correct. CONCLUSION: The simplified ERG procedures performed in our series were reliable in detecting achromatopsia. However, it may not be sufficient to discriminate complete from incomplete achromatopsia.

Adolescent↗
PubMedDate not supplied

Albinism.

Albinism includes a group of genetic disorders with decreased pigmentation. Eye defects include foveal hypoplasia and misrouting of retinal nerve impulses. The primary concerns of those with albinism are low vision and societal misconceptions, which can also lead to social and emotional problems. Persons with albinism can live fairly normal lives when they have appropriate support and resources, including low vision rehabilitation.

Adaptation, Psychological↗