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PubMed2004

Four-year incidence of visual impairment: Barbados Incidence Study of Eye Diseases.

OBJECTIVE: To describe the 4-year incidence of visual impairment and causes of blindness among black participants of the Barbados Eye Studies. DESIGN: Population-based incidence study. SETTING AND PARTICIPANTS: The Barbados Incidence Study of Eye Diseases (BISED) followed the cohort of the Barbados Eye Study (BES), a prevalence study based on a simple random sample of Barbadians 40 to 84 years of age. BISED included 3193 black participants from the original cohort (85% of those eligible). MAIN OUTCOME MEASURES: Best-corrected visual acuity (Ferris-Bailey chart) at baseline and follow-up was measured according to a modified Early Treatment of Diabetic Retinopathy Study protocol. By use of World Health Organization (WHO) criteria, low vision and blindness for an individual were defined as visual acuity (VA) <6/18 to 6/120 and <6/120, respectively, in the better eye. By commonly used US criteria, low vision and blindness were defined as VA < or = 20/40 and < or = 20/200, respectively. Vision loss was defined as a doubling of the visual angle (i.e., decrease of 15 letters or more read correctly between baseline and follow-up examinations). Progression was defined as vision loss among those with low vision at baseline. RESULTS: On the basis of WHO criteria, the overall 4-year incidence was 3.6% (95% confidence interval [CI], 3.0%-4.4%) for low vision and 0.6% (95% CI, 0.4%-1.0%) for blindness. Incidence rates were higher using US criteria: 5.3% (95 % CI, 4.5%-6.2%) and 1.5% (95% CI, 1.1%-2.0%), respectively, reaching 21.5% and 7.3% for persons aged 70 years or older at baseline. One tenth of the cohort had vision loss, and 28.6% of those with low vision progressed. About one half of incident blindness was due to age-related cataract. Nearly one fifth was caused by open-angle glaucoma (OAG) alone or combined with cataract, and approximately 10% was caused by diabetic retinopathy (DR). CONCLUSIONS: The incidence of visual impairment was high in this Afro-Caribbean population, particularly in older age groups, indicating the public health significance of visual loss for this and similar black populations. Cataract, OAG, and DR were among the leading causes of incident blindness, paralleling their high prevalence in this population.

Adult↗
PubMedDate not supplied

Prevalence of blindness in a rural ophthalmically underserved Nigerian community.

A blindness prevalence survey was performed in Ifedapo Local Government Area of Oyo state in Nigeria to provide baseline data for evaluation and monitoring of eye care services in the area. In the ten villages selected for the survey, an average urban migration rate of 27.8% per year was found. 1973 persons were examined. Three persons were blind in both eyes and 18 were blind in one eye alone. Eleven people suffered low-vision in both eyes, while 35 suffered low-vision in one eye only. The community prevalence rate of blindness (WHO definition) was 0.15% and prevalence rate of low-vision (WHO definition) was 0.56%. The three blind patients were age 70, 58 and 70 years respectively. They were a male and two females. The mean age of the low vision-group 56 years and the male:female ratio was 1:2. The major causes of low-vision and blindness were cataracts, senile macular degeneration, glaucoma, non-trachomatous corneal opacities and uncorrected refractive errors. It is reckoned that 58% of the blindness is treatable. Another 13% could have been avoided if good ophthalmic services were available. About 13% was irreversible and 13% of the aetiology of blindness was unknown.

Adolescent↗
PubMed2006

[Quality control in rehabilitation of patients with visual impairment: evaluation of use and benefits of optic and electronic devices].

BACKGROUND: Not only medical care and prescription of magnifying devices, but also social and professional rehabilitation are part of a complete interdisciplinary low vision service. This study provides quantitative data about the success of rehabilitation and the quality of the Low Vision Department's work. PATIENTS AND METHODS: A sample of 105 visually disabled patients, who had already been provided with magnifying aids and other rehabilitation measures by the Low Vision Department, answered a questionnaire about quality control during a follow-up visit. The survey was carried out between May and October 2004. Patients were asked to rate the different rehabilitation measures and to comment on how frequently they used the different magnifying devices. Furthermore, they were asked to judge to what degree they coped with different life situations when using or not using the low vision aids. RESULTS: The most frequently used aids were magnifiers (61%), glasses for near vision (34%), closed circuit television (20%), and monocular telescopes (20%). Of the 105 patients, 85 (81%) reported on frequent use of the devices, with just 3 patients (3%) reporting that they hardly ever used the aids. Only 2% of the patients could read newspaper text without the use of magnifying aids, while 51% were able to do this using the aids; 46% of the patients reported that they had profited from the social and professional rehabilitation measures. CONCLUSION: Independently from the causal ophthalmologic diagnosis, patients were found to have benefited greatly from the rehabilitation measures provided by the Low Vision Department, enabling them to take part in more activities and participate more fully in social life, thereby greatly improving their quality of life. Frequent use of the low vision aids by the patient was ensured when offered alongside continued professional support.

Aged↗
PubMed2001

Eye movements and reading with large print and optical magnifiers in macular disease.

PURPOSE: Reading rate has been the main performance measure in studies that have compared reading with large print and optical magnifiers; eye movement characteristics have not been considered. We compared both eye movement characteristics and reading rates for subjects with macular disease reading without and with a range of low-vision devices. METHODS: Silent reading rate and eye movement characteristics for text passages at critical print size of 21 subjects aged 14 to 88 years with macular disease were measured with and without their preferred low-vision device. Saccadic frequency was determined from a sequencing task comprising five letters each separated by 5 degrees. Eye movements were recorded using an infrared limbal reflection system. RESULTS: There were no significant differences in reading rate, fixation durations, saccade numbers per word, or percent retrace time when using a low-vision device compared with reading without a low-vision device. The percentage of regressions was, however, lower with the low-vision device. Saccadic frequency in the sequencing task was predictive of reading performance with and without a low-vision device. CONCLUSIONS: When reading at critical print size, in terms of reading rate or saccades per word, there was no advantage to using large print over an optical low-vision device.

Adolescent↗
PubMedDate not supplied

[Ocular disorders causing blindness in working-age outpatients: a prospective study at the African Institute of Tropical Ophthalmology (IOTA, Bamako, Mali)].

UNLABELLED: The objective of this study was to determine the different groups of ocular disorders causing low vision or blindness among working-age patients consulting at the African Institute of Tropical Ophthalmology (IOTA) in Bamako, Mali. METHODS: This prospective study took place from 1 February through 8 April, 2003, at IOTA. It included all new patients aged between 18 and 50 years, regardless of whether they worked, but excluding students. RESULTS: 828 patients were recruited: 384 men (46.4%) and 444 women (53.6%). The average age was 35.7 years. The rate of bilateral blindness was 5.8%, of low vision 8.5%, and of blindness in one eye 11.5%. Men and women did not differ significantly in rates of bilateral blindness (p = 0.77) or low vision (p = 0.24), but blindness in a single eye affected men (67.4%) more often than women (32.6%, p = 0.01). While the frequency of bilateral blindness and low vision increased with age, blindness in one eye affected all ages. We observed no significant differences according to ethnic group in the prevalence of bilateral blindness and low vision, both observed most frequently among housewives, farmers and low-income workers, most illiterate. The major causes of bilateral blindness were cataracts 29.2%, glaucoma 22.9%, trachoma 14.6%, ocular manifestations linked to HIV/AIDS 8.3%, and non-glaucomatous optical neuropathies 8.3%. Half the cases (50.5%) of blindness in one eye resulted from ocular trauma, and five cases from HIV/AIDS (5.3%). Low vision resulted from impaired refraction 22.9%, cataract 17.2%, trachoma 15.7%, glaucoma 10% and corneal opacities 5.7%. DISCUSSIONS: The high rate of blindness and low vision are associated with the study site: a reference center whose population was composed completely of patients with vision problems. The causes of blindness and low vision have not changed over time except for the ocular manifestations of HIV/AIDS, which is among the most important current causes of blindness, because of the lack of antiretroviral treatments in sub-Saharan Africa. If nothing stops this pandemic, it will soon modify epidemiological data about blindness. CONCLUSION: Blindness and visual deficiencies, already a public health problem, will become an important socioeconomic burden in sub-Saharan Africa and may even stop progress among low-income countries.

Adolescent↗
PubMed1999

Reading with a head-mounted video magnifier.

PURPOSE: This study compared the effectiveness of a head-mounted video magnifier, low-vision enhancement system (LVES), with closed-circuit TV (CCTV) and large print as a device or means of improving reading performance in people with low vision. METHODS: The reading performance of ten low-vision participants was assessed in two ways: (1) By measuring reading speed as a function of print size with LVES and without LVES, and (2) by comparing reading speed and comprehension of news articles using the LVES vs. a popular non-head-mounted video magnifier, the CCTV. RESULTS: Maximum reading speeds with LVES matched the maximum reading speeds with unaided vision attained by enlarging print. The critical print size (the smallest print size that could be read at maximum reading speed) improved significantly for all participants using LVES compared with unaided vision. When comparing reading performance using LVES and CCTV, we found that reading speed and comprehension for the two conditions were equivalent. The two low-vision participants with lowest acuities (20/640 and 20/960) could not read the 10-point newspaper articles with LVES, even with an 8 D auxiliary reading lens that permitted a very close reading distance. CONCLUSIONS: Head-mounted video magnifiers, such as LVES, can support good low-vision reading performance, but the restricted range of magnification may limit the usefulness of the device as a reading magnifier for people with very low acuity.

Adult↗
PubMed2004

Causes and prevalence of visual impairment among adults in the United States.

OBJECTIVES: To estimate the cause-specific prevalence and distribution of blindness and low vision in the United States by age, race/ethnicity, and gender, and to estimate the change in these prevalence figures over the next 20 years. METHODS: Summary prevalence estimates of blindness (both according to the US definition of < or =6/60 [< or =20/200] best-corrected visual acuity in the better-seeing eye and the World Health Organization standard of < 6/120 [< 20/400]) and low vision (< 6/12 [< 20/40] best-corrected vision in the better-seeing eye) were prepared separately for black, Hispanic, and white persons in 5-year age intervals starting at 40 years. The estimated prevalences were based on recent population-based studies in the United States, Australia, and Europe. These estimates were applied to 2000 US Census data, and to projected US population figures for 2020, to estimate the number of Americans with visual impairment. Cause-specific prevalences of blindness and low vision were also estimated for the different racial/ethnic groups. RESULTS: Based on demographics from the 2000 US Census, an estimated 937 000 (0.78%) Americans older than 40 years were blind (US definition). An additional 2.4 million Americans (1.98%) had low vision. The leading cause of blindness among white persons was age-related macular degeneration (54.4% of the cases), while among black persons, cataract and glaucoma accounted for more than 60% of blindness. Cataract was the leading cause of low vision, responsible for approximately 50% of bilateral vision worse than 6/12 (20/40) among white, black, and Hispanic persons. The number of blind persons in the US is projected to increase by 70% to 1.6 million by 2020, with a similar rise projected for low vision. CONCLUSIONS: Blindness or low vision affects approximately 1 in 28 Americans older than 40 years. The specific causes of visual impairment, and especially blindness, vary greatly by race/ethnicity. The prevalence of visual disabilities will increase markedly during the next 20 years, owing largely to the aging of the US population.

Adult↗
PubMed2001

Prevalence and causes of visual impairment in The Barbados Eye Study.

OBJECTIVE: To determine the prevalence and causes of low vision and blindness in a predominantly black population. DESIGN: Population-based prevalence study of a simple random sample of Barbados-born citizens aged 40 to 84 years. PARTICIPANTS: Four thousand seven hundred nine persons (84% participation). METHODS: The standardized protocol included best-corrected visual acuity (with a Ferris-Bailey chart), automated perimetry, lens gradings (LOCS II), and an interview. Participants with visual acuity of worse than 20/30, other positive findings, and a 10% sample also had an ophthalmologic examination that evaluated the cause and extent of vision loss (resulting from that cause), if any. MAIN OUTCOME MEASURES: Low vision and blindness were defined as visual acuity in the better eye between 6/18 and 6/120 and visual acuity worse than 6/120, respectively (World Health Organization [WHO] criteria). RESULTS: Of the 4631 participants with complete examinations, 4314 (93%) reported their race as black, 184 (4%) reported their race as mixed (black and white), and 133 (3%) reported their race as white or other. Low vision was found in 5.9% of the black, 2.7% of the mixed, and 3.0% of white or other participants. Bilateral blindness was similar for black and mixed race participants (1.7% and 1.6%, respectively) and was not found in whites. Among black and mixed participants, the prevalence of low vision increased with age (from 0.3% at 40-49 years to 26.8% at 80 years or older). The prevalence of blindness was higher (P < 0.001) for men than women at each age group (0.5% versus 0.3% at ages 40-49 and 10.9% versus 7.3% at 80 years or more). Sixty percent of blindness was due to open-angle glaucoma and age-related cataract, each accounting for more than one fourth of cases. Other major causes were optic atrophy or neuropathy and macular and other retinal diseases. Few cases of blindness were due to diabetic retinopathy (1.4%), and none were due to age-related macular degeneration. CONCLUSIONS: Using the WHO criteria, prevalence of visual impairment was high in this African-origin population, particularly at older ages. Most blindness was due to open-angle glaucoma and cataract, with open-angle glaucoma causing a higher proportion of blindness than previously reported. The increased prevalence of blindness in men may be due to the increased male prevalence of glaucoma in this population and warrants further investigation. Results underline the need for blindness prevention programs, with emphasis on effective treatment of age-related cataract and enhancing strategies for early detection and treatment of open-angle glaucoma.

Adult↗
PubMed2006

Vision rehabilitation for Canadians with less than 20/40 acuity: the SmartSight model.

Traditionally, vision rehabilitation was directed towards patients who were blind or had very low vision. There is increasing evidence that less severe vision loss is associated with increased risk of falls, hip fractures, medication errors, poor nutrition, reduced physical activity, social isolation, clinical depression, longer hospitalizations, and mortality. The American Academy of Ophthalmology (AAO) 2003 SmartSight initiative in low vision rehabilitation outlined a model of graduated low vision interventions. This paper is a review of the AAO SmartSight model and how it can apply in the Canadian setting. All patients with visual acuity less than 20/40, a scotoma, field loss, or loss of contrast sensitivity would be offered information about available low vision rehabilitation. Eye physicians would be encouraged to communicate with other health care providers to coordinate existing services and integrate graduated services. Enhanced communication among caregivers about the consequences of vision loss, such as depression, falls, and visual hallucinations, could help ensure that all patients who would benefit receive appropriate vision rehabilitation.

Canada↗
PubMed2004

Prevalence and causes of visual impairment in an elderly Chinese population in Taiwan: the Shihpai Eye Study.

OBJECTIVE: Few population-based data on the prevalence and causes of visual impairment are available from East Asia. The purpose of this study was to determine the prevalence and causes of visual impairment in an elderly Chinese population in Taiwan. DESIGN: Population-based cross-sectional study. PARTICIPANTS: The Shihpai Eye Study was a survey of vision and ocular disease among an elderly Chinese population 65 years of age or older residing in Shihpai, Taiwan. A random sample of 2045 elderly residents was identified and selected from the household registration databank. Among them, 1361 (66.6%) underwent a detailed ophthalmic examination. METHODS: The ophthalmic examination included best-corrected visual acuity measurements using standardized protocols. Visual acuity was assessed with a Snellen E chart. The major cause of visual loss was identified for all participants who were visually impaired. MAIN OUTCOME MEASURES: Low vision and blindness were defined as a best-corrected visual acuity in the eye with better vision worse than 20/60 to a lower limit of 20/400 and worse than 20/400, respectively, according to World Health Organization categories of visual impairment. RESULTS: The mean age of the participants was 72.2 (range, 65-91) years old. A total of 40 participants met the World Health Organization criteria of low vision, and 8 were diagnosed as blind. The rate of blindness and low vision was estimated to be 0.59% (95% confidence interval, 0.25%, 1.16%) and 2.94% (95% confidence interval, 2.11%, 3.99%), respectively. There was a significant increase in the rate of low vision (P<0.001) from 0.83% at 65 to 69 years of age to 8.33% at age 80 years or older. There was no gender difference in the prevalence of blindness or low vision. The leading cause of visual impairment was cataract (41.7%), followed by myopic macular degeneration (12.5%) and age-related macular degeneration (10.4%). CONCLUSIONS: The rate of blindness and low vision is close to that reported for other developed countries. The high frequency of myopic macular degeneration as a major cause of visual loss, however, is not observed in European-derived populations. Specific prevention or low-vision rehabilitation programs should be developed for the elderly Chinese population.

Aged↗
PubMed1998

[Image flicker frequency of television reading aids. Effect on reading comfort for visually handicapped patients].

PURPOSE: To compare reading speed and reading comfort between closed-circuit television systems (CCTVs) with different image refresh rates. METHODS: Reading speed was measured with three CCTVs that only differed in repeat frequency (50, 60 and 70 Hz) in 21 patients with age-related macular degeneration and 10 controls. We compared reading speed measured in syllables per minute of 16 different reading templates with about 500 syllables each. RESULTS: Reading speed was equal with all CCTVs. Eighteen of 21 patients identified and disliked 50 Hz CCTVs because the image quality was worse. An image quality of 70 HZ enabled patients to use positive contrast with the best reading speed. CONCLUSIONS: Although reading speed does not improve with increasing frequency, flickering of 50 Hz CCTVs is critical for low-vision patients. The preference of low-vision patients for negative contrast image is more likely due to flickering with a lower repeat rate and 70 Hz CCTVs may allow more comfortable reading in positive contrast.

Aged↗
PubMed1996

[Social status of visually handicapped patients in new combined federal Germany--a comparison with the status before 1990].

In the wake of German unification, great social change has taken place in some fields. To estimate the impact of these changes on the state of rehabilitation of people with low vision, a standardized questionnaire about their social situation was sent to those 134 adult graduates of the School for People with Low Vision in Thuringia who had already been interviewed in 1989. 56 completed questionnaires could be evaluated, and the data was compared with the data collected in 1989. While there was almost no change concerning medical rehabilitation, an interesting development in the field of financial and social benefits has taken place: Even though the number of people who qualified for support had increased from 41.1% (1989) to 62.5% now, a closer look showed that this had mainly been caused by financial benefits (such as unemployment pay, housing subsidy, etc.) linked to the social decline of the examined group of disabled people. Accordingly, the number of employed people with low vision had decreased from 98.2% in 1989 to 60.7% today. Nevertheless all respondents seem to be secure financially (increase of the net income per month and household for 48.2% of the respondents) and fortunately 78.6% lived in their own flat (compared to only 64.3% in 1989). The general liberalization of public life in the new German Laender is reflected by the fact that 19.6% of the people with low vision felt able to make new friends and that traveling (with 50%) ranked second among the hobbies mentioned. The views people with low vision hold relative to the general living conditions illustrate a general uncertainty in the wake of the changes in the entire social system (statement: "Everything has become insecure"--55.4%), but also reveals that better economic background conditions are appreciated.

Adolescent↗
PubMed2002

[Analysis of visual prognosis and correlative factors in retinal vein occlusion].

OBJECTIVE: To investigate the visual prognosis, risk factors, complications and the causes of visual deterioration in patients with various types of retinal vein occlusion (RVO). METHODS: Nine hundred and forty-four eyes of 913 patients with various types of RVO were analyzed. The age range of patients was 15 - 89 years (average 52.8 +/- 11.9), and the average follow-up was 20.7 months. The data of the patients were studied by SPSS software. RESULTS: (1) RVO was classified into central RVO (CRVO) in 406 eyes of 391 cases (43.0%), hemi-RVO (HRVO) in 60 eyes of 60 cases (6.4%) and branch RVO (BRVO) in 478 eyes of 462 cases (50.6%). (2) They were subdivided into ischemic type in 633 eyes (67.1%) and non-ischemic type in 311 eyes (32.9%). (3) The visual prognosis: the average initial visual acuity (VA) in CRVO, HRVO and BRVO was 0.36, 0.38 and 0.40 respectively. The average final VA was 0.40 in CRVO (P > 0.05), 0.50 in HRVO (P > 0.05) and 0.58 in BRVO (P < 0.05). (4) The initial VA and prognosis: there was close relationship between initial VA and visual prognosis. If the initial VA >/= 0.5, the final acuity maintained >/= 0.5 in 70.6% in CRVO, 75.0% in HRVO and 84.9% in BRVO. The patients with initial VA </= 0.l had final VA worse than 0.1 in 66.2% of CRVO, 35.7% of HRVO and 25.3% of BRVO (P < 0.01). (5) Low vision and the rate of blindness in RVO: Among the 205 eyes with low vision (21.7%), there were 27.6% with CRVO, 31.7% with HRVO and 17.2% with BRVO (P < 0.01). Among the 160 eyes with blindness (16.9%), There were 27.6% with CRVO, 11.7% with HRVO and 8.6% with BRVO (P < 0.01). (6) The visual prognostic comparison between ischemic type and non-ischemic type: there were 189 of 633 eyes with ischemic type (29.9%) and only l6 of 311 eyes with non-ischemic type (5.1%) had low vision. In the ischemic type, 157 eyes had blindness (25.1%) and 3 eyes with non-ischemic type (1.0%) had blindness (P < 0.01). (7) Risk factors of RVO were hypertension (57.8%), arteriosclerosis (67.4%), high blood viscosity (24.6%), diabetes (6.2%) and primary glaucoma (1.5%). (8) Complications of RVO: cystoid macular edema (CME) 46.7%, retinal neovascularization (RNV) 21.5%, vitreous hemorrhage 11.4% and neovascular glaucoma (NVG) 9.6% (39/406) in CRVO and 1.7% (1/60) in HRVO. (9) Low vision caused by CME was 37.9%, and RNV 29.9%; blindness in CME 19.5% and RNV 23.0%. In 40 eyes with NVG, the final VA was worse than 0.05 in 38 eyes (95.0%). CONCLUSION: The rate of blindness of RVO is high, and the visual prognosis of ischemic type is worse. There is close relationship between the level of initial VA and visual prognosis. CME, RNV and NVG are important causes of blindness.

Adolescent↗
PubMed2005

Age-related eye diseases: an emerging challenge for public health professionals.

In April 2004, The Eye Disease Prevalence Research Group published a series of articles that included age-specific estimates for the prevalence of low vision and blindness in whites, African Americans, and Hispanics living in the United States. Also included were age-, sex-, and ethnic-specific incidences of the following age-related eye diseases: diabetic retinopathy, macular degeneration, cataracts, and glaucoma. We reviewed the group's series of articles and highlighted key findings on the overall prevalence of and risk factors for age-related eye diseases, as well as opportunities to preserve and restore vision. We examined publications that show the public health impact of age-related eye diseases and the importance of projected increases in prevalence of low vision and blindness. Approximately 1 in 28 Americans aged older than 40 years is affected by low vision or blindness. Among community-dwelling adults, the prevalence of low vision and blindness increases dramatically with age in all racial and ethnic groups. Whites have higher rates of macular degeneration than African Americans, but glaucoma is more common among older African Americans. Between 2000 and 2020, the prevalence of blindness is expected to double. Age-related eye diseases are costly to treat, threaten the ability of older adults to live independently, and increase the risk for accidents and falls. To prevent vision loss and support rehabilitative services for people with low vision, it is imperative for the public health community to address the issue through surveillance, public education, and coordination of screening, examination, and treatment.

Black or African American↗
PubMed1999

[Ophthalmological rehabilitation - experience at the University Eye Hospital Heidelberg].

BACKGROUND: The rehabilitation of low vision patients is of increasing importance since the number of these patients has grown rapidly. We wanted to evaluate the actual spectrum of patients concerning age and diagnoses and the appropriate low vision aids (LVA) in 1 year. METHODS: The records of the patients seen in our low-vision unit in 1996 were retrospectively evaluated. We correlated visual function, ophthalmological diagnoses and age to the magnification needed for rehabilitation and the use or prescribed LVAs. RESULTS: There was a nearly homogeneous distribution concerning age with a range from 0 to 99 years. Most patients presented with age-related macular degeneration (25.6 %) while 10 % each had retinitis pigmentosa and optic atrophy. Simple low vision aids such as high plus reading additions (29 %) and magnifiers (18.5 %) were prescribed in the majority of patients. However, closed-circuit TV (CCTV) systems were necessary in 25 %. CONCLUSIONS: Rehabilitation of low vision patients is often possible with simple LVAs. This is especially true for patients suffering from age-related macular degeneration. Since there is a tremendous-amount of different diseases, adequate diagnostic and individual counseling is of major importance.

Adolescent↗
PubMed2000

Implementation methods for vision related quality of life questionnaires.

AIM: To determine the most reliable and consistent method and time interval over which to implement a vision impairment quality of life assessment tool. METHODS: 117 patients with low vision aged 9-101 years were assigned into three age, sex, and visual function matched groups (n = 39 in each) to answer the Low Vision Quality of Life (LVQOL) questionnaire by post, telephone, or in person. The LVQOL questionnaire was completed on four occasions, each separated by four weeks. RESULTS: Postal implementation was the most cost effective method, showed the highest internal consistency of LVQOL items, but resulted in a lower apparent quality of life score than either telephone or in-person interviews (p<0.001). There was no difference in test-retest reliability between the three methods of implementation (p = 0.12). The profile of LVQOL scores showed a trend towards reduced quality of life scores 3 months after the baseline measures, although this was not significant. CONCLUSION: Posting may be the method of choice for clinical measurement of vision related quality of life. Patients with greater visual impairment were no less likely to complete a questionnaire when implemented by post and there was no apparent bias from other people assisting them. The quality of life measure can occur at any time up to 2 months after low vision rehabilitation for the progressive nature of conditions causing low vision not to cause a decreased baseline score. The LVQOL was shown to be a highly internally consistent and reliable method for measuring quality of life in the visually impaired.

Adolescent↗
PubMedDate not supplied

[Visual rehabilitation in patients with retinitis pigmentosa].

PURPOSE: To determine which low-vision aids could be useful to patients with retinitis pigmentosa and also the benefits that the rehabilitation program could provide based on visual acuity and/or daily visual tasks. METHODS: A group of 30 patients with retinitis pigmentosa aged from 7 to 73 years were enrolled in this study. Visual acuity and visual function tests (visual field, full-field electroretinogram) was performed and low-vision aids tested. Information about the use of the remaining vision was obtained. After choosing the best optical or electronic devices and before their prescription, a low-vision training program was carried out. RESULTS: The best corrected visual acuity varied from HM (hand movements) to 20/40 for distance and visual acuity better than 16M to 0.5M for near. 90% of the patients had optical devices prescribed: 13 for near, 9 for distance, 2 electronic devices and 3 filters. Three patients with extremely narrow visual field and very low visual acuity were referred to orientation and mobility. CONCLUSIONS: The low-vision aids were useful for the retinitis pigmentosa patients: telescopes, hand-held magnifiers, stand magnifiers, half-eye base-in prism lenses, electronic devices and illumination control were beneficial to enhance visual acuity and visual efficiency. The prescription of low-vision aids was helpful in daily-life activities and a high level of satisfaction with the implemented visual rehabilitation program was reported.

Adolescent↗
PubMed1998

Benefits of rapid serial visual presentation (RSVP) over scrolled text vary with letter size.

We previously reported that low vision readers do not benefit from a rapid serial visual presentation (RSVP) display relative to a scroll display. Each reader in those studies was presented with only one letter size, and it was the same for both displays. In the current study, we systematically varied the size of the letters and compared reading rates from the 2 displays for letters that were 2, 4, 6, 8, and 10 times each reader's acuity threshold. Using this paradigm, we found that subjects with normal vision (n = 12) read faster with RSVP for all text sizes. Low vision subjects (N = 20) showed no benefit of RSVP until the text was at least 8x their acuity threshold. As in our prior studies, there was a great deal of variability within the low vision group, and for a small number of subjects (25%), reading was faster from the scroll than from the RSVP display.

Aged↗