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PubMed2005

Color vision tests for aviation: comparison of the anomaloscope and three lantern types.

INTRODUCTION: A comparison of the results obtained with the Nagel anomaloscope and the Holmes-Wright Type A, Spectrolux, and Beyne aviation color vision lanterns was undertaken. The Joint Aviation Requirements (JAR) specify pass/fail limits for these four secondary color vision tests and the Ishihara screening test. The results for individuals on all five tests were studied. METHODS: The color vision of 55 color-vision deficient and 24 color-vision normal subjects, mostly applicant pilots, was assessed using a battery of tests, including the Ishihara plates, the Nagel anomaloscope, and three lanterns. The testing methods and characteristics of the lanterns and anomaloscope were compared. RESULTS: Of the color-deficient applicants, only deuteranomalous trichromats passed more than one of the four secondary JAR tests, but a pass on one test did not reliably predict a pass on another test. Three out of nine protanomalous trichromats passed the Nagel anomaloscope but failed all three lantern tests. Of the normal trichromats, 12 failed the anomaloscope and 12 failed the Beyne lantern. DISCUSSION: Variability in pass/fail results can be attributed to many factors apart from loss of chromatic sensitivity. Some normal trichromats can fail both the Ishihara screening and the secondary tests. The approved secondary test varies between countries and the outcome of regulatory assessment depends on the color vision test used. Since the flight safety consequences of the current situation cannot be ignored, the development of a less variable technique for color vision assessment that is accepted internationally, allied with a better understanding of color vision requirements, is needed.

Aerospace Medicine↗
PubMed1993

Optometric trends in sports vision: knowledge, utilization, and practitioner role expansion potential.

BACKGROUND: The optometric discipline of sports vision is a relatively young and actively growing area which has spurred the interest of optometrists and sports organizations at the high school, college, and professional levels. METHODS: 473 optometrists were surveyed and compared to a similar survey sent to 100 optometrists in 1980 and 1983. Also, college and professional teams were surveyed. RESULTS: Optometrists felt there were more opportunities available in sports vision. Contact lenses, particularly soft lenses, were found to be continued in favor over rigid lenses, and nearly half surveyed have utilized vision training in their practices. College and professional sports suggest a broader acceptance and utilization of sports vision services. CONCLUSIONS: Since the establishment of the American Optometric Association Sports Vision Section (AOA-SVS) fourteen years ago, advances have been made in utilization and acceptance of sports vision worldwide. However, this survey demonstrates that despite the increase of vision care consultants, there is still an unmet need for vision care/screening services at the collegiate and professional levels.

Contact Lenses, Hydrophilic↗
PubMed1995

[Binocular vision in idiopathic macular foramen. Pre- and postoperative findings].

In recent years idiopathic macular hole has become an increasingly frequent indication for vitrectomy. To our knowledge, the literature contains no studies comparing binocular vision before and after vitrectomy. We therefore carried out a prospective study not only on visual acuity following vitrectomy but also, for the first time, on binocular vision. Stereopsis and fusion were evaluated in 37 patients with idiopathic macular holes (stage I-IV) using Bagolini striated glasses, the Titmus stereotest (contour stereopsis), the random dot test (global stereopsis), the Worth four-dot test and the phase-difference haploscope. The tests were performed preoperatively and 10-12 weeks after vitrectomy. Two patients with stage I macular hole showed no loss of stereopsis in conventional tests. One patient, however, exhibited suppression tendencies with partial exclusion. The 18 patients with stage II macular hole had a relative good visual acuity of 0.2-0.6, but subnormal binocular vision with marked suppression of foveal images. Postoperatively, the majority of these patients had symptom-free binocular vision and good stereopsis. Some, however, continued to experience foveal exclusion. Patients with macular hole stage III and IV (n = 17) had the poorest results. Although the postoperative visual acuity improved by 2 to 3 points in some patients (n = 6), in approximately one third it remained limited to global peripheral binocular vision. In summary, our findings show that even in early stages (I and II), macular hole can cause not only reduced visual acuity but also impairment or, in stage II, even loss of binocular vision. Vitrectomy in these early stages often leads to an overall improvement in visual acuity and binocular vision, whereas in more advanced stages vitrectomy often does not affect visual acuity and binocular vision. This should be taken into account when weighing up the indications for surgery.

Aged↗
PubMed2006

Reading aids for adults with low vision.

BACKGROUND: The purpose of low vision rehabilitation is to allow people to resume or to continue to perform daily living tasks, reading being one of the most important. This is achieved by providing appropriate optical devices and special training in the use of residual vision and low vision aids, which range from simple optical magnifiers to high power video magnifiers. OBJECTIVES: The objective of this review was to assess the effects of reading aids for adults with low vision. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) in The Cochrane Library, MEDLINE, EMBASE, SIGLE, LILACS, IndMed to July 2006 and the reference lists of relevant articles. We used the Science Citation Index to find articles that cited the included studies and contacted investigators and manufacturers of low vision aids. We handsearched the British Journal of Visual Impairment from 1983 to 1999 and the Journal of Visual Impairment and Blindness from 1976 to 1991. SELECTION CRITERIA: This review included randomised and quasi-randomised trials in which any device or aid used for reading had been compared to another device or aid in people aged 16 or over with low vision as defined by the study investigators. DATA COLLECTION AND ANALYSIS: Each author independently assessed trial quality and extracted data. MAIN RESULTS: Eight small studies with a cross-over design (221 people overall) and one three parallel-arm study (243 participants) were included in the review. The cross-over studies evaluated various types of aids. The quality of the studies was unclear in most cases, especially concerning carry-over or period effects. In one study on 20 participants head-mounted electronic devices (four types) were worse than optical devices. We could not find any differences in comparisons among electronic devices when pooling 23 participants of two small studies. One study on 10 people found that overlay coloured filters were no better than a clear filter. A parallel-arm study including 243 patients with age-related macular degeneration found that custom or standard prism spectacles are not different from conventional near spectacles, but the estimated difference was not precise. AUTHORS' CONCLUSIONS: Further research is needed on the comparison of different types of low vision aids. It will be also necessary to delineate patient's characteristics that predict performance with costly electronic devices as well as their sustained use in the long term compared to simpler and cheaper optical devices.

Adult↗
PubMed2005

Relationship of cataract symptoms of preoperative patients and vision-related quality of life.

BACKGROUND: This study was conducted in an attempt to describe the status of cataract symptoms of preoperative cataract patients, as well as to determine the relationship between cataract symptom and vision-related quality of life measures. RESEARCH DESIGN: A cross-sectional study design was used. Study subjects were selected using non-probabilistic methods. The study sample consisted of 132 patients scheduled for cataract surgery in one eye. Information was obtained from study subjects by conducting face-to-face interviews. PARTICIPANTS: Study subjects were adult cataract patients at Samsung and Kunyang General Hospitals in Seoul, Korea, and Tulane University Hospital and Clinics in New Orleans, Louisiana, United States of America. MEASUREMENTS: Degree to which study subjects were "bothered" by cataract symptoms was measured by using the 5-item Cataract Symptom Scores (CSS). The number of symptoms, highest scored symptom among the five, number of symptoms extremely bothering, and the mean of cataract symptom score were created based on the CSS measure. Vision-related quality of life was assessed by using the Visual Function 14 Items (VF-14) and Global Measure of Vision (GMV) for trouble and satisfaction. RESULTS: The symptoms "blurry vision" and "worsening of vision" were most frequently reported. The symptom "colors looking different" was rarely reported among preoperative cataract patients. The degree to which study subjects were bothered by "blurry vision" and "seeing glare, halo, or rings" was highly associated with visual function, visual trouble, and visual satisfaction. Multiple regression analysis revealed that the newly developed cataract symptom-related scales, as well as total amount of degree to which study subjects were "bothered" by symptoms were highly related to vision-related quality of life measures. These relationships were persistent after controlling for major socio-demographic variables. CONCLUSIONS: The results indicate that cataract symptoms are highly associated with vision-related quality of life. The results also suggest that the number of symptoms, highest scored symptom among the five, number of symptoms extremely bothering, and the mean cataract symptom scores should be considered an important cataract symptom-related scale when analyzing quality of life, including cataract symptom.

Aged↗
PubMed2004

Why do mice have ultra-violet vision?

Murine vision has become a fascinating entity due to discoveries about the histology and physiology of its retina over the past decade. It has two varieties of cones, one serving the traditional green-yellow region of the vision spectrum and another serving the ultra-violet region, essentially invisible to man and many other mammal. This puts unusual constraints on the optical transmission of the murine eye, in particular its relatively large lens. Its ultra-violet vision appears to involve its upper much more than its lower visual field, providing a heuristic clue to its purpose. In addition behavioural evidence exists for colour vision in mice. On the other hand there is unequivocal evidence that many murine cones contain both cone photopigments, an unrealistic but not impossible arrangement for colour vision. A better understanding of how ultra-violet vision is interwoven into cone and rod vision and possible colour vision can be clarified by analysing the responses of single retinal neurons. This paper reviews the current information on this topic and provides new insights from single retinal ganglion cell recordings.

Animals↗
PubMed2002

Risk, causes, and outcomes of visual impairment after loss of vision in the non-amblyopic eye: a population-based study.

BACKGROUND: Screening for amblyopia in early childhood is done in many countries to ensure that affected children are detected and treated within the critical period, and achieve a level of vision in their amblyopic eye that would be useful should they lose vision in their non-amblyopic eye later in life. We aimed to investigate the risk, causes, and outcomes of visual impairment attributable to loss of vision in the non-amblyopic eye. METHODS: For 24 months from July, 1997, national surveillance was done to identify all individuals in the UK with unilateral amblyopia (acuity worse than 6/12) who had newly acquired vision loss in the non-amblyopic eye, resulting in acuity of worse than 6/12 or visual-field restriction precluding driving. Information about participants was obtained at presentation and 1 year later. Participants were categorised as having socially significant visual impairment, or visual impairment, severe visual impairment, or blindness, in accordance with WHO taxonomy. FINDINGS: Of 370 eligible individuals, at presentation 104 (28%) had socially significant visual impairment, 180 (49%) visual impairment, and 86 (23%) severe visual impairment or blindness. The minimum risk of permanent visual impairment by age 95 years was 32.9 (95% CI 29.1-36.9) per 100,000 total population. The projected lifetime risk of vision loss for an individual with amblyopia was at least 1.2% (95% CI 1.1-1.4). Only 36 (35%) of 102 people previously in paid employment were able to continue. INTERPRETATION: In the UK, where screening for amblyopia is under review, risk of serious vision loss affecting the non-amblyopic eye and its results are greater than that previously assumed. Thus, in addition to the benefits of improved vision in the amblyopic eye, treatment of amblyopia during childhood is a potentially valuable strategy to prevent incapacitating vision loss later in life.

Adolescent↗
PubMed1999

Detection of color vision defects in chloroquine retinopathy.

OBJECTIVE: The effect of chloroquine toxicity on color vision is unclear. The authors identified the color defects seen in chloroquine retinopathy and determined the sensitivity and specificity of clinical color vision tests for detecting the presence of previously diagnosed chloroquine retinopathy. DESIGN: Case-control study. PARTICIPANTS: Chloroquine retinopathy was defined using previously published criteria. Data from 30 patients with retinopathy and 25 patients using chloroquine but with no evidence of retinal toxicity were collected. METHODS: All patients were tested with the following six clinical color vision tests: Ishihara, Farnsworth D-15, and Adams Desaturated-15 (Dsat-15), City University 2nd Edition (CU), Standard Pseudoisochromatic Plates Part 2 (SPP-2), and American Optical Hardy Rand Rittler (AO HRR). MAIN OUTCOME MEASURES: The number of failures was determined for each test. The types of color vision defects were classified as blue-yellow (BY), red-green (RG), or mixed RG and BY (mixed). RESULTS: Of the 30 patients with retinopathy, 28 (93.3%) of 30 patients failed at least 1 color vision test, demonstrating predominantly mixed defects. Five (25%) of 25 of the control subjects failed at least 1 test, and these defects were predominantly BY. The sensitivity and specificity of the tests are as follows: SPP-2 (93.3%, 88%), AO HRR (76.7%, 88%), Ishihara (43.3%, 96%), Dsat-15 (33.3%, 84%), D-15 (16.7%, 96%), and CU (20%, 92%). CONCLUSIONS: Color vision can be affected by chloroquine and should be tested routinely with a color vision test designed to detect both mild BY and protan RG defects to maximize sensitivity for toxicity. The SPP-2 and AO HRR are two tests that meet these criteria. The Ishihara has a low sensitivity, as do the D-15 tests and CU. All of the tests have similar specificity for chloroquine toxicity. If color vision defects are detected in patients at risk of developing chloroquine retinopathy, additional testing is indicated to rule out toxicity.

Adult↗
PubMed2003

Color vision.

Many visual disorders produce acquired color vision defects. Color vision theory emphasizes several stages of visual processing: prereceptoral filters (lens, macular pigment, pupil), cone photopigments (L-, M-, and S-cones), and postreceptoral processes (red-green, S-cone, and luminance channels). Congenital color defects, which affect 8% to 10% of males and 0.4% to 0.5% of females, result from alterations in the photopigment absorption spectra or the absence of one or more photopigments. The most common defects are color vision deficiencies (protan and deutan defects), which are milder than the rarer achromatopsias (complete loss of color vision). Acquired color vision defects can be attributed to a number of different causes: alteration of prereceptoral filters, reduced cone photopigment optical density, greater loss of one cone type than the others, and disruption of postreceptoral processes. Acquired color vision defects have been divided into three classes: type 1, red-green defect with scotopization; type 2, red-green defect without scotopization; and type 3, blue defects (with or without pseudoprotanomaly). Blue defects are usually type 3 acquired defects because congenital tritan defects have an incidence of one in several tens of thousands. Red-green defects can be acquired or congenital, and ruling out acquired defects can require a battery of tests (plates and arrangement tests, anomaloscopy, perhaps genetic analysis). Color vision tests must be administered carefully (with a standard illuminant and protocol), and pupillary miosis or high lens density should be noted and their possible effects considered when interpreting test results. Plate tests provide a simple screening method but do not provide a diagnosis. Arrangement tests and anomaloscope testing take more time and make greater demands on the tester, but they provide a more thorough evaluation. When standard protocols are followed and results are interpreted in terms of prereceptoral filters, photopigment optical density, cone loss, and disruption of postreceptoral processes, a battery of color vision tests can be useful in the differential diagnosis, after progression of the disease, and for evaluating the effectiveness of treatment.

Color Perception↗
PubMedDate not supplied

Vision impairment and handicap: The RVIB Employment Survey. The Steering Committee for the RVIB Employment Survey.

PURPOSE: The purpose of this study was to examine the association between type of vision impairment and disability and the handicap or impact of vision loss on functioning. METHODS: Participants were interviewed for the Royal Victorian Institute for the Blind Employment Survey, and asked to self-report whether totally blind or not (vision impaired). Causes of visual impairment were also reported. Eyesight was rated on a scale from 0 (completely blind) to 10 (best possible eyesight). Difficulty with mobility, personal care, household activities, work and hobbies and social interactions were also rated. Participants with vision impairment also rated their level of disability in reading and seeing other people's reactions using the same scale. RESULTS: Of the 250 participants, 39 self-reported total blindness. Participants with vision impairment experienced greater levels of difficulty in almost all areas than people who self-reported total blindness. People with vision impairment due to glaucoma and macular degeneration reported significantly more difficulty with reading newspapers, while there was a borderline significant relationship between difficulty with seeing people's reactions and macular degeneration. CONCLUSIONS: In summary, we found that difficulty associated with everyday tasks was greater than might be expected from self-report of vision. This study confirms the need for visual function tools to supplement the use of objective visual acuity measurements in people with vision impairment.

Activities of Daily Living↗
PubMed1999

The role of pattern vision in the development of cortico-cortical connections.

The development of cortico-cortical connections was studied in kittens deprived of vision by binocular eyelid suture during the formation of axonal arbors and synaptogenesis, i.e. between the second postnatal week and the end of the third postnatal month. Axons originating in area 17 and terminating either in ipsilateral or contralateral visual areas were visualized with biocytin. In ipsilateral areas 17 and 18, distinct clusters of branches begin to form, distally from the injection, during the second half of the first postnatal month, independently of pattern vision. More proximal clusters differentiate during the second postnatal month, and this seems to involve elimination of exuberant axonal branches. In kittens deprived of vision for 3 or more months, beginning before natural eye opening, the distal clusters regress and the proximal ones fail to differentiate. In extrastriate areas, distinct clusters of branches have segregated by the end of the second postnatal month, independently of visual experience; however, in kittens deprived of vision for 2 or more months, one of the clusters was selectively eliminated. In contralateral areas 17 and 18, we found stunted terminal arbors in kittens continuously deprived of vision. This was already noticeable at the end of the first postnatal month. Apparently, in the absence of pattern vision, most axons undergo only limited growth and do not form their characteristic terminal columns. Many of these axons are subsequently eliminated. In contrast, 8 days of vision beginning at natural eye opening and followed by visual deprivation caused a nearly normal development of intrahemispheric and interhemispheric connections. In conclusion, pattern vision appears to validate connections at early stages of their development; this validation is necessary for their further growth and differentiation that can then continue autonomously.

Animals↗
PubMed1994

Does color vision deficiency in the endoscopist influence the accuracy of endoscopic diagnosis? An anonymous study with Dutch gastrointestinal endoscopists.

Colors play a major role in the endoscopic diagnosis of many gastrointestinal conditions. Gastrointestinal endoscopists in the Netherlands are predominantly male (> 90%), and from population data it is to be expected that approximately 8% will have a color vision deficiency. The present study was designed to assess the prevalence of color vision deficiencies amongst Dutch gastrointestinal endoscopists and to determine whether color vision deficiency affects an endoscopist's diagnostic skill. One hundred and thirty-nine gastroenterologists and physicians of internal medicine took an F2 color vision test and assessed nine videofragments of endoscopies. Color vision deficiencies were detected in 8% of Dutch gastrointestinal endoscopists. In one out of the nine video excerpts of endoscopies, a statistically significant difference was detected between test subjects with and without a color vision deficiency. However, this video excerpt showed a green pea, which could not be mistaken for a polyp at polypectomy. The study therefore does not show any effect of color vision deficiencies on endoscopic skills, nor does it show any deviant prevalence of color vision deficiencies amongst Dutch gastrointestinal endoscopists.

Adult↗
PubMed2000

Color vision defects after central serous chorioretinopathy.

PURPOSE: To reexamine patients diagnosed with central serous chorioretinopathy (CSC) during the 10-year period from 1987 to 1996 to identify remaining color vision defects in the eyes with normal visual acuity (VA). METHODS: Thirty-nine patients were found with normal VA of 20/20 (logMAR 0) or better 8 to 166 months (mean +/- SD, 58.8 +/- 41.2) after active CSC. Color vision was examined with the Standard Pseudoisochromatic Plates part 2, Farnsworth-Munsell 100 hue test, and Color Vision Meter 712 anomaloscope. RESULTS: Of the CSC eyes, 26 (67%) had a color vision defect, most of them in the blue area. There was no correlation between the time since the active disease and the results on the color vision tests. Of the contralateral eyes, 19 (49%) also had a color vision defect. CONCLUSION: In many patients some degree of color vision defect remains after CSC even if the VA has recovered to normal. The contralateral eye can also have a color vision defect. This has not been previously reported and might be due to earlier subclinical CSC.

Adult↗
PubMed2005

Night driving self-restriction: vision function and gender differences.

PURPOSE: The purpose of this study was to evaluate gender differences in the relationship between night driving self-restriction and vision function in an older population. METHODS: Night driving self-restriction patterns (assessed by questionnaire) were examined cross-sectionally in relation to age, gender, health and cognitive status, depression, and vision function in a sample of 900 elders (mean age, 76 years) living in Marin County, California. RESULTS: Of the total sample, 91% of men and 77% of women were current drivers. The mean age of the drivers was 73.3 years (range, 58-96 years). Among current drivers, women had slightly better vision function than men on most measures (low-contrast acuity, contrast sensitivity, low-contrast acuity in glare, low-contrast, low-luminance acuity, and glare recovery) but were twice as likely as men to restrict their driving to daytime. Men showed significant associations with avoidance of night driving on four spatial vision measures (high- and low-contrast acuity, low-contrast, low-luminance acuity, and contrast sensitivity). For women, in addition to these measures, a significant association was seen for low-contrast acuity in glare. Neither men nor women showed significant associations between driving restriction and performance on the other vision measures examined (glare recovery time, attentional field integrity, or stereopsis). The vision measures most predictive of self-restriction were contrast sensitivity for men and low-contrast acuity in glare for women. CONCLUSIONS: Including both cessation and self-restriction, men over age 85 years are 6.6 times more likely than women to be driving at night. For both genders, vision plays a significant role in the self-restriction decision. A higher percentage of men than women continue to drive at night with poor vision. Men's night-driving cessation was associated with contrast sensitivity and depression, whereas women's night-driving cessation was associated with low-contrast acuity in glare as well as age.

Accidents, Traffic↗
PubMed1996

Depression and disability in older people with impaired vision: a follow-up study.

OBJECTIVE: To determine the prevalence of depressive symptoms and their relationship to disability in older low vision patients. DESIGN: Panel study with 2-year follow-up. PARTICIPANTS: Community-residing older people (N = 31). MEASUREMENTS: Geriatric Depression Scale, Community Disability Scale, and Snellen visual acuity. RESULTS: Twelve of 31 patients (38.7%) had GDS scores > or = 11 at baseline. Two years later, 10 of these 12 patients remained depressed, and three of the 19 (15.8%) previously nondepressed patients had become depressed. Depressed patients tended to be more disabled functionally than nondepressed patients at follow-up. The correlation of disability with depression and with vision were examined for the entire sample and revealed a strong correlation between disability and depression (r = .40; P = .013) compared with that of disability and vision (r = .34; P = .032) at baseline and at follow-up: depression (r = .68; P = .001), vision (r = .45; P = .006). There was no significant correlation between depression and vision at baseline (r = .06; P = .383), but there was a trend toward correlation at follow-up (r = .28; P = .067). CONCLUSION: Depressive symptoms are prevalent and persistent among low vision patients and appear more highly related to disability than is vision. The frequent occurrence of depression and the availability of effective treatment argue for its recognition and treatment as possible ways to reduce disability in older persons with low vision.

Activities of Daily Living↗
PubMed1998

Depression and disability associated with impaired vision: the MoVies Project.

OBJECTIVE: To assess how depression and impaired vision relate to disability in older people. DESIGN: An epidemiological survey of an age-stratified random community sample. SETTING: The rural mid-Monongahela Valley in South-western Pennsylvania. PARTICIPANTS: A total of 872 noninstitutionalized persons aged 68 and older, fluent in English, and with at least a grade 6 education. MEASUREMENTS: Demographics, self-reported vision impairment, OARS Instrumental Activities of Daily Living (IADL), and modified Center for Epidemiologic Studies-Depression scale to assess depression. RESULTS: Compared with subjects with intact vision, those with impaired vision were more likely to have five or more depressive symptoms (29.7% vs 8.5%; OR = 4.6, 95% CI = 2.2, 9.6) and to be more functionally impaired (OR = 9.7, 95% CI = 4.9, 19.2). The number of depressive symptoms (1-4: OR = 2.4, CI = 1.8, 3.4) and (5+: OR = 5.9, CI = 3.6, 9.8) was associated independently with IADL impairment after controlling for vision, age, and gender. CONCLUSIONS: Impaired vision and depression are both associated strongly with functional impairment in this community population of older adults. Depression, however, increases the odds of functional impairment independent of vision impairment. Treating depression may reduce excess disability associated with impaired vision.

Activities of Daily Living↗
PubMed2006

Colour vision defects in asymptomatic carriers of the Leber's hereditary optic neuropathy (LHON) mtDNA 11778 mutation from a large Brazilian LHON pedigree: a case-control study.

AIMS: To determine if asymptomatic carriers from a previously identified large pedigree of the Leber's hereditary optic neuropathy (LHON) 11778 mtDNA mutation have colour vision deficits. METHODS: As part of a comprehensive analysis of over 200 members of a large Brazilian LHON pedigree spanning seven generations, colour vision tests were obtained from 91 members. Colour vision was tested one eye at a time using the Farnsworth-Munsell 100 (FM-100) hue colour vision test. The test was administered under uniform conditions, taking into account: ambient light levels, daylight colour temperature of 6700 kelvin, and neutral uniform background. Tests were scored using the FM-100 MS-Excel computer scoring program. Defects were determined and categorised as tritan, deutan, or protan. Categorisation of each dyschromatopsia was based on review of demonstrated axis computer generated plots and age adjusted error scores which coincided with Verriest 95% confidence intervals. Only the axis with the greatest magnitude error score was used to classify the defect. 55 of the 91 test subjects were LHON mtDNA 11778 J haplotype mutation carriers, proved by mtDNA analysis. The remaining 36 subjects were age matched non-blood relatives (off pedigree), who served as controls. RESULTS: 27 of 55 carriers (49.10%) were shown to have colour vision defects in one or both eyes. 13 of the 27 (48%) abnormal tests in the carrier group were tritan defects and the remaining 14 (52%) were deutan defects. Nine of the 27 (33%) abnormals in the carrier group were identified as having bilateral defects. Six of these were deutan, and the remaining three were tritan dyschromatopsias. Only six of the 36 (16.66%) age matched controls were found to have any type of dyschromatopsia. Five (83.3%) of these were deutan defects. The remaining one was a tritan defect. The difference between the two groups using a chi(2) test with one degree of freedom was statistically significant with a p value less that 0.001. CONCLUSIONS: Until now, LHON has always been characterised by a sudden, devastating vision loss. Asymptomatic carriers, those without vision loss, were considered unaffected by the disease. It now appears that asymptomatic carriers of the LHON mutation are affected by colour vision defects and may manifest other subtle, yet chronic, changes.

Brazil↗
PubMed2003

Causes of low vision and blindness in rural Indonesia.

AIM: To determine the prevalence rates and major contributing causes of low vision and blindness in adults in a rural setting in Indonesia METHODS: A population based prevalence survey of adults 21 years or older (n=989) was conducted in five rural villages and one provincial town in Sumatra, Indonesia. One stage household cluster sampling procedure was employed where 100 households were randomly selected from each village or town. Bilateral low vision was defined as habitual VA (measured using tumbling "E" logMAR charts) in the better eye worse than 6/18 and 3/60 or better, based on the WHO criteria. Bilateral blindness was defined as habitual VA worse than 3/60 in the better eye. The anterior segment and lens of subjects with low vision or blindness (both unilateral and bilateral) (n=66) were examined using a portable slit lamp and fundus examination was performed using indirect ophthalmoscopy. RESULTS: The overall age adjusted (adjusted to the 1990 Indonesia census population) prevalence rate of bilateral low vision was 5.8% (95% confidence interval (CI) 4.2 to 7.4) and bilateral blindness was 2.2% (95% CI 1.1 to 3.2). The rates of low vision and blindness increased with age. The major contributing causes for bilateral low vision were cataract (61.3%), uncorrected refractive error (12.9%), and amblyopia (12.9%), and the major cause of bilateral blindness was cataract (62.5%). The major causes of unilateral low vision were cataract (48.0%) and uncorrected refractive error (12.0%), and major causes of unilateral blindness were amblyopia (50.0%) and trauma (50.0%). CONCLUSIONS: The rates of habitual low vision and blindness in provincial Sumatra, Indonesia, are similar to other developing rural countries in Asia. Blindness is largely preventable, as the major contributing causes (cataract and uncorrected refractive error) are amenable to treatment.

Adult↗