[The optic disc in mass screening of chronic open-angle glaucoma].
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Chronic Disease↗
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Results for “Vision Screening”
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Learning effect among perimetric novices with screening C-20-1 frequency doubling technology perimetry.
PURPOSE: To investigate whether perimetric novices without glaucoma demonstrate a learning effect using screening-mode frequency doubling technology perimetry. DESIGN: Prospective observational study. METHODS: The study included 101 healthy subjects who had never undergone automated perimetry and who were administered the C-20-1 version of the frequency doubling technology. Subjects who returned an abnormal or unreliable test were retested until a normal result was obtained. RESULTS: Ninety-seven subjects (96%) returned a normal examination after one test, and 99 (98%) did so after two tests. Two subjects had abnormal initial tests, and two others had unreliable tests. These four subjects required repeat (up to four) testings to return a normal test. CONCLUSIONS: A small percentage of perimetric novices will demonstrate a learning effect using C-20-1 perimetry, but this mode has high specificity appropriate for glaucoma screening.
Adolescent↗
Does frequency doubling technology perimetry reliably detect neurological visual field defects?
AIM: To determine the ability of frequency doubling technology (FDT) perimetry to detect visual field defects of neurological origin. METHODS: A total of 15 eyes of nine patients who all had complete hemianopias or quadrantanopias underwent the FDT 20-5 screening mode test and Humphrey 24-2 SITA Fast visual field test (HFA). The FDT results were scored according to the number of abnormal test locations (out of a maximum of 4) in each affected quadrant. FDT locations showing a defect of P< 2% were considered abnormal. RESULTS: Of the 15 eyes, six showed complete superior quadrantanopic and nine complete hemianopic field defects on HFA. Of 96 FDT test locations in these quadrants or hemifields only 38 were abnormal on FDT testing (40%). For the quadrantanopic field defects, five out of 24 locations were abnormal (21%). For the hemianopic field defects, 33 out of 72 locations were abnormal (49%). In three eyes (two with quadrantanopias and one with complete hemianopia), FDT perimetry failed to demonstrate any corresponding abnormality. CONCLUSIONS: The FDT screening test can fail to demonstrate complete hemianopic and quadrantanopic field defects. Users should be aware of this deficiency when using FDT to screen for field defects.
Adolescent↗
Update and implications from the Newcastle diabetic retinopathy study.
Over 11 years from 1977 a large study of diabetic retinopathy has been conducted in Newcastle and in 1988, 5519 diabetic subjects had been assessed. Where possible, all had retinal photography. Prevalence rates for any retinopathy, proliferative retinopathy and maculopathy were assessed in relation to the known duration of diabetes for subjects diagnosed before or after age 30 years. These data indicate a peak of retinopathy prevalence in the second or third decade of diabetes with slightly lower rates in longer survivors. Treatment with insulin was associated with a higher retinopathy prevalence. Incidence rates for the new development of background retinopathy in previously unaffected subjects show a peak late in the first decade of diabetes in young-onset cases, while in the older-onset group, the peak occurs in the second decade of diabetes. Over all, 8% of diabetics without retinopathy developed it per year. The implications of this data for the routine management of diabetic patients is discussed and the current recommendations for retinal screening by the Australian Diabetes Society are outlined.
Adult↗
An epidemiological study of the ocular and visual profiles of Oklahoma Cherokees and Minnesota Chippewas.
Over the last three decades some American Indian tribes in North America have received attention in the literature as a minority group with unique visual characteristics. Studies on the refractive status of Indians have shown an increase of refractive errors and particularly an abnormally high prevalence, and amount of, with-the-rule astigmatism. These changes appear to have taken place over the last 40 years. Eskimos, on the other hand, have recently showed an astoundingly high incidence of myopia. Other Native American tribes do not show dramatic changes in myopia or astigmatism. The Public Health Service-Indian Health Service, as an ongoing aspect of their responsibilities to Native Americans, perform screenings on children. This study reports the results of visual screenings primarily of Oklahoma Cherokee and Minnesota Chippewa children.
Astigmatism↗
[Vision and work on a video screen].
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Data Display↗
Sensitivity of the MTI photoscreener for amblyogenic factors in infancy and early childhood.
BACKGROUND: Screening for amblyogenic factors in infancy by pediatricians is unsatisfactory, as they hardly ever detect ametropia or microstrabismus. As photoscreening seems to be a helpful method to detect even small squint angles and refractive errors, we tested the MTI photoscreener for its sensitivity with respect to amblyogenic factors. PATIENTS AND METHODS: One hundred and twelve children aged 6-48 months were first examined with the MTI photoscreener. Then each child underwent complete medical examination by an ophthalmologist and an orthoptist. The examination included the Hirschberg test (corneal reflex evaluation), the Brückner test (fundus red reflex), and, where possible, the Lang stereotest, the cover test and visual acuity assessment, as well as a motility test, biomicroscopy, ophthalmoscopy in mydriasis and refractometry in cycloplegia. Exclusion criteria were any organic pathological results, manifest strabismus, ametropia > or = 2 D and astigmatism > or = 1 D. An orthoptist, a pediatrician and two ophthalmologists independently evaluated the Polaroid pictures according to the criteria given in the handbook of the MTI photoscreener. RESULTS: For 10 children the evaluation with the MTI photoscreener was not possible despite the fact that photographs were retaken several times. Thirteen photographs showing obvious pathologic findings despite their poor quality were included. Eighty-three of the remaining 102 children failed the eye examination according to the above-mentioned criteria. The mean sensitivity of the MTI photoscreener was determined to be 82.8%. The ability to correctly identify the absence of any amblyogenic factors (specificity) was 61.8%. CONCLUSIONS: Sensitivity was high when compared to the usually low detection rate during pediatric examinations. Due to the low specificity, effectiveness was poor. Therefore an ophthalmological examination should be included in the preventive screening during infancy and early childhood.
Amblyopia↗
Screening and preventable illness.
If an agent does not discount the future at a constant rate, as in some forms of myopia, her optimal strategy is unattainable without some commitment device. We apply this familiar idea to a model of screening and disease prevention, and explore how financial incentives can correct suboptimal health choices. In general, myopia need not imply under-screening. While the optimal intervention for prevention effort is a state-invariant subsidy, the optimal intervention for screening may involve a tax or a subsidy. When screening and prevention are coincident, a simple and practical subsidy equal to one minus the discount factor to both screening and intervention is indicated.
Cost of Illness↗
The evaluation of screening policies for diabetic retinopathy using simulation.
AIMS: To develop a model for evaluating screening strategies and to use it to determine the cost effectiveness of varying the screening method and the screening interval. METHODS: A discrete event simulation was designed, validated and run for a population of 500000. Most parameters were derived from peer-reviewed publications. RESULTS: Standard methods of screening save up to 50% of the potential sight years lost. They give up to 85% of the sight years saved by an idealized gold standard programme using mydriatic seven-field photography reported by an ophthalmologist. The mobile camera, used for annual screening and 6-month follow-up after the detection of background retinopathy, had an estimated cost of pound 449200 per year with pound 2842 per sight year saved. It is less efficient to screen Type 2, rather than Type 1 diabetes mellitus patients, but they contributed to almost three-quarters of the sight years saved. CONCLUSIONS: The model can evaluate screening intervals and methods on a national or health authority basis. Results indicate that it appears more cost effective to continue to screen outside an ophthalmology clinic, until treatment is needed. Programmes with annual screening, and more frequent screening for those with background retinopathy, are robust to realistic fluctuations in compliance and screening sensitivity.
Computer Simulation↗
Screening for retinopathy of prematurity--a comparison between binocular indirect ophthalmoscopy and RetCam 120.
AIM: To compare the photographic screening for retinopathy of prematurity (ROP) using RetCam 120 with binocular indirect ophthalmoscope (BIO), which is the current gold standard. SETTING AND DESIGN: Prospective, comparative study. MATERIALS AND METHODS: A total of 87 RetCam examinations were performed on 27 premature babies. They were stored in a separate file after deleting the identifying information. At the same visit using the BIO with scleral depression, an experienced vitreoretinal surgeon evaluated the fundus in detail. A masked examiner then evaluated the RetCam photographs for presence or absence of ROP, the stage and zone of the disease and the presence or absence of plus disease. These data were then compared with the BIO findings to determine the sensitivity, specificity and the positive and negative predictive values of the method. RESULTS: ROP was detected in 63 of 87 examinations by BIO and in 56 of 87 RetCam examinations. Nine RetCam examinations were false-negative and two were false-positive. Sensitivity of RetCam was 85.71% (54/63) and specificity was 91.66% (22/24). The positive and negative predictive values were 96.43% and 70.97% respectively. CONCLUSION: Nine cases having ROP were missed by the RetCam. All these cases were either in zone 3 or the outer part of zone 2, which later regressed. These were missed mostly because of the restricted mobility of the camera head caused by its size and the barrier caused by the lid speculum arms. No case of threshold ROP was missed. RetCam may replace BIO for screening of ROP.
Diagnosis, Differential↗
Portable tonometers: a clinical comparison of applanation and indentation devices.
Optometric services to outpatient clinics, nursing homes and hospitals require portable equipment for ocular assessment. Of the various tonometric methods available, Goldmann applanation tonometry remains the standard. We present a clinical comparison of the hand-held version of Goldmann's instrument (Perkins tonometer) and the less expensive Schiotz tonometer. In a clinical comparison, we measured the intraocular pressure (IOP) of 51 inpatient and outpatient veterans (100 eyes) during routine examination. In each case the Perkins applanation tonometer was used first. This measurement was followed by IOP measurements using the Schiotz indentation tonometer with the 7.5 g and 5.5 g plunger loads. Plunger loads were alternated so that each was used, initially, 50% of the time. Good correlations, ranging from +.85 to +.68, were achieved between the applanation and indentation modes. Compact portability, lower cost and comparable reliability make the Schiotz tonometer a viable option for IOP screening.
Adult↗
Detection and prevention of treatable visual failure in general practice: room for improvement?
An ageing population, the introduction of sight test charges and a problem that has never been adequately addressed since the inception of the National Health Service presents general practitioners with the increasing burden of detecting and preventing visual failure which they feel poorly equipped to deal with. Ophthalmology in general practice is a fundamental requirement for the reduction of avoidable visual failure and this is probably especially true for elderly patients and diabetic patients. A postal survey of general practitioners in Brent and Harrow suggests that there is potential for major improvements in the delivery of eye care by general practitioners, often without much additional expenditure (the equipment is there but it is not used) and with minimal training requirements. Simple changes in already existing screening programmes could potentially have an immediate effect on the visual well-being of the community.
Aged↗
[Glaucoma in Munster].
BACKGROUND: The question was: are all persons with glaukoma in the town of Munster in treatment? MATERIAL AND METHODS: The author recorded all patients with glaucoma and were subdivided into the different glaucoma diseases. The author analysed 10 glaucoma screenings of white populations published in the past 30 years and compared these with the glaucoma population in Munster. RESULT: The results of these comparisons are ambiguous. In one survey (Tierp) 50% more POAG patients were found than are known in Munster; another (Baltimore) had the same distribution as Munster. CONCLUSION: With our knowledge about the course of untreated glaucoma, such uncertainty is, in tolerable, and the author suggests that glaucoma screening be offered to part of the population, like cancer screening.
Adolescent↗
Glaucoma screening by optometrists: positive predictive value of visual field testing.
PURPOSE: Visual field testing is increasingly being performed by optometrists in order to improve glaucoma detection. The aim of this study was to assess the positive predictive value (PPV) of visual field testing as currently practised by optometrists. METHODS: A retrospective study was performed of referrals for suspected glaucoma to an ophthalmology department during a 3 month period. The PPV for glaucoma was determined according to the reason for referral. RESULTS: There were 86 referrals for suspected glaucoma. Isolated field loss accounted for 12% of these referrals but no cases of glaucoma detection. These subjects were either false positive referrals or had field defects of nonglaucomatous aetiology (tilted optic disc and porencephalic cyst). The PPV for glaucoma among referrals with isolated field loss was significantly less than that among referrals with field loss in association with corroborative abnormalities (0 vs. 60%, p = 0.005). No such difference was found for referrals with raised intraocular pressure (43% vs. 57%, p = 0.38) or suspicious discs (25% vs. 53%, p = 0.60). CONCLUSIONS: Visual field testing is currently leading to unnecessary referrals to the hospital eye service with no detectable improvement in the accuracy of glaucoma suspect referrals. It is important that optometrists perform visual field testing in accordance with validated screening methodology.
Adult↗
Comparison of the Retinomax autorefractor with hand-held retinoscopy in 1-year-old infants.
This study aimed to determine the accuracy (and usability) of the Retinomax, a hand-held autorefractor, compared to measurements taken from hand-held retinoscopy (HHR) in a sample of normal 1-year-old children. The study was a method comparison set at four Community Child Health Clinics. Infants (n = 2079) of approximately 1 year of age were identified from birth/immunization records and their caregivers were contacted by mail. A total of 327 infants ranging in age from 46 weeks to 81 weeks (mean 61 weeks) participated in the study. The children underwent a full ophthalmic examination. Under cycloplegia, refraction was measured in each eye by streak retinoscopy (HHR) and then re-measured using the Retinomax autorefractor. Sphere, cylinder, axis of cylinder and spherical equivalent measurements were recorded for HHR and Retinomax instruments, and compared. Across the range of refractive errors measured, there was generally close agreement between the two examination methods, although the Retinomax consistently read around 0.3 D less hyperopic than HHR. Significantly more girls (72 infants, 47.7%), struggled during examination with the Retinomax than boys (52 infants, 29.5%) (P < 0.001). Agreement deteriorated between the two instruments if the patient struggled during the examination (P < 0.001). In general, the Retinomax would appear to be a useful screening instrument in early childhood. However, patient cooperation affects the accuracy of results and is an important consideration in determining whether this screening instrument should be adopted for measuring refractive errors in early infancy.
Female↗
Laser pointer visual field screening.
BACKGROUND: Sensitivity of confrontation visual field (CVF) screening is low unless defects are significant. We compared the sensitivity of laser pointer visual field screening (LVF) with conventional CVF for identifying eyes with abnormal automated perimetry. METHODS: Ninety consecutive patients presenting for HVF prospectively underwent a masked comparison of CVF and LVF testing (175 eyes) from April to May 2000. LVF was performed using a laser pointer target projected onto a tangent screen. Points were tested in random fashion on either side of the vertical and horizontal meridians, near central fixation, around the blind spot, and in each quadrant. Single and double simultaneous finger counting was used to test CVF. RESULTS: LVF demonstrated significantly greater sensitivity as compared with CVF (73% versus 31%, P = 0.001) in identifying field defects found on HVF. Specificities for LVF and CVF were 82% and 99%, respectively. The average testing times per eye were 0.5 minute for CVF, 1.5 minutes for LVF, and 8.0 minutes for HVF. CONCLUSIONS: In this cohort, laser visual field testing was significantly more sensitive than confrontation testing. It may represent an effective, time-efficient tool for visual field screening.
Cohort Studies↗
Evaluation of screening versus regular polarimetry.
PURPOSE: The purpose of this study is to evaluate a new screening program for the GDx VCC (variable corneal compensation) retinal nerve fiber layer analyzer. This new method uses a fast screening approach to detect retinal nerve fiber layer loss associated with glaucoma. The study evaluates the sensitivity and specificity of the screening program and compares the results with those from the GDx VCC full examination. METHODS: One hundred seventeen eyes from 60 subjects with a mean age of 60.65 years (range, 41-79 years old) were analyzed. Subjects were divided into a normal or glaucoma group based on an ophthalmic examination. Each individual underwent a GDx VCC screening examination, GDx full examination, Humphrey HFA II 24-2 SITA Standard visual field, intraocular pressure assessment, and dilated optic nerve examination. The outcome for the GDx screening examination was within normal limits, borderline, or outside normal limits and compared with the GDx full examination results. RESULTS: The sensitivity and specificity for the GDx full examination were 73% and 79%, respectively. The sensitivity and specificity for the screening method were 67% and 91%, respectively. The full examination was more sensitive; however, the screening examination was more specific. CONCLUSION: The screening examination is more conservative than the full examination algorithm and may miss some individuals with glaucomatous damage that the full examination may identify. However, the number of false-positives for the screening examination is less than the full examination method.
Adult↗
Amiodarone and optic neuropathy.
PURPOSE: To investigate the clinical, perimetric, contrast sensitivity and visual evoked potentials findings in patients on longterm treatment with amiodarone. METHODS: We enrolled 14 patients (age range 47-78 years, mean age 62.7 years) on chronic amiodarone therapy (mean cumulative dose of 519 g), and 14 age-matched control subjects. Participants were submitted to ophthalmological examination, kinetic visual field testing (Goldmann), standard achromatic automated perimetry (central 30-2, Humphrey), computerized isoluminant chromatic contrast sensitivity (CCS) and pattern visual evoked potentials evaluation (VEP). Data from baseline, 6-month and 1-year follow-up examinations were analysed. The main outcome measures were: initial and final corrected visual acuity; corneal, optic disc and fundus abnormalities; mean deviation (MD) and pattern standard deviation (PSD) central 30-2 perimetry parameters; visual field loss on kinetic perimetry; indices of CCS (tritan, protan and deutan axes), and pattern VEP latency (L-VEP) and VEP amplitude (a-VEP). RESULTS: We found a statistically significant difference between the patients and controls' baseline L-VEP and a-VEP measurements (p < 0.001). We found no significant correlation between prolonged L-VEP and duration of amiodarone use (r = 0.07). After a 1-year follow-up, we evidenced an average increment in L-VEP of 1.96 ms and a-VEP measurements showed a decline of 0.69 micro V. In cumulative dose-specific analyses, mean differences between baseline and 12-month L-VEP measurements were more evident in those taking higher than 200 g cumulative amiodarone doses (p = 0.03). We found abnormal tritan CCS results in 19 eyes (68%). Of these, four eyes belonged to patients with no ocular disease (diabetes, cataracts). No significant differences were observed between the baseline and 12-month clinical eye examinations, central 30-2 perimetry and CCS results. CONCLUSION: We found a significant prolongation in pattern L-VEP and a significant reduction in pattern a-VEP in patients on longterm treatment with amiodarone compared to control subjects. Nevertheless, current data are insufficient to recommend appropriate methods of visual screening.
Aged↗