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Biomedical subjects

A Heijl

Publications and source records attributed to A Heijl.

89 records · Page 5Linked to original sources
PubMed1983

Visual field and retinal nerve fibre layer in early glaucoma after optic disc haemorrhage.

Computerized visual field testing with the Competer automatic perimeter including automatic profile perimetry revealed early glaucomatous field loss in 9 of 10 eyes with photographically demonstrable retinal nerve fibre layer (RNFL) defects after optic disc haemorrhages despite the fact than conventional routine perimetry had failed to do so. In 7 of these cases the Competer central pattern test was abnormal; in 2 cases field defects could be shown only when automatic high-resolution static profile perimetry was performed and directed according to the information present in wide-angle RNFL photographs. A field defect was also found in one of five eyes with no photographic RNFL changes. Visual field defects seem to occur in a higher proportion of cases with RNFL defects than was previously thought, but they can be very subtle and hard to find. There are, however, cases where in spite of the presence of an indisputable RNFL defect no visual field defects can be shown even with painstaking technique and conversely field defects may be present without RNFL defects. Automatic perimetry and RNFL photography complement each other in early detection and quantitation of glaucomatous damage.

Aged↗
PubMed1983

Changes in differential threshold in patients with glaucoma during prolonged perimetry.

Patients with chronic open-angle glaucoma and others suspected of having glaucoma were subjected to continuous contrast threshold measurement by automatic and manual perimetric techniques. The results show that an increase of contrast threshold over time is a frequent finding in glaucoma patients and that this increment can be large, especially at points close to existing field defects. it is reproducible and independent of background illumination and can be demonstrated with both automatic and manual testing, but it is larger in the automatic than in the manual mode of testing. The results may have some important implications for visual field testing in glaucoma.

Differential Threshold↗
PubMed1981

A clinical comparison of three computerized automatic perimeters in the detection of glaucoma defects.

The ability to detect glaucomatous field defects of three automatic computerized perimeters (COMPETER, OCTOPUS, and PERIMETRON) was compared in a clinical study of 74 patients. This study included patients with glaucoma, those with suspected glaucoma in whom the visual fields were completely normal, and normal subjects. The reference fields were obtained by careful static and kinetic manual perimetry on the Tübinger perimeter. All the automatic instruments gave similar high rates of detection of visual field loss and low false-positive test results. Quantity conventional manual perimetry is necessary to support automatic perimetric results, but automatic perimeters already can do a large proportion of routine perimetric screening.

Adult↗
PubMed1980

Automatic perimetry (COMPETER). Ability to detect early glaucomatous field defects.

The ability of fully automatic computerized perimetry to detect early glaucomatous field damage was compared with that of careful static and kinetic manual perimetry in a clinical study on 104 patients, 51 of whom had early glaucomatous field defects, 20 of whom were glaucoma suspects with no field defects, and 33 of whom were normal. The automatic perimeter used was the COMPETER automatic perimeter employing actual threshold measurements. The interpretation of the automatic fields followed a set of predetermined criteria. Fifty-one eyes had defects in the manual charts, 48 (94%) of which were detected by automatic perimetry using the central test point pattern of the perimeter. Two (4%) fields thought to be normal after manual perimetry were correctly found to be abnormal by the automatic perimeter, which yielded four (8%) false-positives in the normal fields. By using a different set of criteria for the interpretation of the automatic fields, the sensitivity could be increased to 98% of these early defects, but at the cost of 22% false-positives.

Adult↗
PubMed1980

Computerized profile perimetry in glaucoma.

The new profile testing mode of the COMPETER automatic perimeter was clinically tested and compared with careful manual profile perimetry on the Tübinger perimeter. Each of 110 patients with glaucomatous field defects, patients with suspected glaucoma, and normal subjects had one meridian tested. All of the 55 patients who showed an abnormal result on the manual profile also had abnormal findings on the automatic test. Two (4%) of the profiles labeled as normal on initial manual perimetry were identified by the automatic perimeter to be abnormal, and these defects were confirmed on repeated manual profile perimetry. The automatic perimetry gave five (9%) false-positive results in the 53 normal manual profiles, thus giving a specificity of 91%. In two of these cases, the automatic profile indicated defects in areas where the manual profile appeared normal, but there was abnormality in the manual kinetic perimetry in the affected area. The automatic profiles of the COMPETER automatic perimeter are accurate, sensitive, time-saving, and clinically useful.

Adolescent↗
PubMed1980

Computerized visual field screening in the management of patients with ocular hypertension.

Visual field testing which the Computer fully automatic computerized perimeter (Heijl & Krakau 1975) employing a supra-liminal screening test procedure was used in a material of 1013 eyes with ocular hypertension in which earlier routine perimetry (kinetic and static) on the Goldmann perimeter had yielded a normal result. The automatic screening was repeated if positive, and manual control perimetry was used in order to confirm or reject identified field defects. This procedure revealed field defects that could be confirmed at both automatic and manual perimetry in 3.6% of the eyes. In the control group the incidence of field defects found at manual perimetry during the same time interval was calculated at 0.4%. Thus automatic screening revealed several times more field defects than manual routine perimetry. Eyes in which repeated automatic screening had indicated defects which manual control perimetry failed to confirm, showed a high percentage of field loss at later follow-up. The results are discussed, and the conclusion is drawn that automatic screening is clearly superior to manual routine perimetry used at present. The most practical solution in many eye departments would be to use a computerized perimeter for the visual field screening of glaucoma suspects.

Adult↗
PubMed1978

Automatic computerized perimetry in the detection of neurological visual field defects. A pilot study.

Forty-seven eyes from 25 patients with neurological disease were examined with an automatic computerized perimeter primarily intended for glaucoma. Manual kinetic and static perimetry with Goldmann's instrument was used for comparison. In 32 fields, the automatic method disclosed all defects that had been found by manual perimetry. Furthermore, it detected three small defects that had been missed in the initial manual examination. The remaining 12 fields were normally using both methods. Consequently, in detecting field defects, the automatic perimeter was superior to the manual method.

Amblyopia↗
PubMed1977

Time changes of contrast thresholds during automatic perimetry.

Contrast thresholds were continuously recorded in six points of the visual field through a repetitive up-and-down staircase method using the automatic perimeter developed by Heijl & Krakau (1975b). The uninterrupted sessions lasted about 30 min. Nineteen patients with a verified diagnosis of glaucoma, or in whom glaucoma was suspected, and twelve healthy normal subjects were tested. With increasing test time, a decreased contrast sensitivity was found. In most subjects the mean threshold increment was small (less than 1.5 dB). The threshold increments were larger in the patient group than in the normal subjects--many test points showing increments of 6-10 dB during the test session. Such a large deterioration of sensitivity was most common in eyes with visual field defects. Test points which showed large threshold increments were often situated in the vicinity of documented visual field defects. In eyes with pathological visual fields, the short-term variation increased with increasing test time. An impairment of fixation with increasing test time was found in the patient group.

Adult↗
PubMed1977

Computer test logics for automatic perimetry.

Using an automatic computerized perimeter developed by Heijl & Krakau (1975b) three different perimetric test logics, one simple (I) and two more complicated and time-consuming (II & III) were investigated in practical experiments on healthy normal test subjects and patients and in computer simulated tests. The patients either had a verified diagnosis of glaucoma or glaucoma was suspected. The best consistency in measured thresholds was obtained with test logic II, in which an averaging procedure is used. The variation of the results was larger in pathological than in normal visual fields. All test logics investigated readily detected the pathological field defects, but blind spots could easier pass unrecognized with the simplest logic than with the other two logics. The conclusion is drawn that a simple test logic can be used for perimetry in glaucoma suspects if no visual field defect has previously been documented. For the follow-up of pathological fields a fairly complicated test logic, e.g. using averaging, is preferable.

Adult↗
PubMed1977

A note of fixation during perimetry.

Small eye movements in the direction of the disappearing stimulus can be observed at kinetic perimetry when the test object enters a scotomatous area. These may be responsible for the fact that several field defects, missed at routine manual perimetry, are spotted at automatic perimetry. In the latter case the patient cannot predict the position of next test light, since these are illuminated at random, whereas at kinetic perimetry they are exposed in systematic order. By using two specially designed logics in automatic perimetry, it was shown that there may be a reduction of the scotoma size if the lights are exposed in an ordered sequence. This effect is avoided by using a logic with randomly exposed stimuli. It is most likely that the difference can be attributed to "malfixation".

Adult↗
PubMed1976

Automatic perimetry in glaucoma visual field screening. A clinical study.

Automatic computerized perimetry was compared to careful manual selective perimetry (a variant of that proposed by Armaly) in 181 eyes of 100 patients from a glaucoma open-care unit. The results of the two methods were very similar. Thus all defects found were identified by the automatic perimeter, and one pathologic field was missed by the manual selective perimetry. The automatic examination gave 16% false positive results and the manual 11% when optimally performed. The false positives could be greatly reduced (to 4.4% and 3.3% respectively) by rescreening. In a comparison with "routine" perimetry, the automatic screening is shown to be superior.

Adult↗
PubMed1976

A portable hemianopsia tester.

A pocket-size static perimeter provided with four test lights, one for each quadrant of the visual field, has been constructed and applied to 190 visual fields in 97 patients. The main advantage of the instrument is its ability to disclose hemianopic defects in bedridden and certain sick patients unable to co-operate with other methods, including the confromtation test. This was performed in 12 fields in 7 patients.

Adolescent↗
PubMed1975

An automatic perimeter for glaucoma visual field screening and control. Construction and clinical cases.

An apparatus for static perimetry of the central visual field at 64 points is described. The testing is fully automatic: the test logic is programmed into a mini-computer and the results are plotted as a diagram in polar coordinates. A few cases with small or medium sized visual field defects have been analyzed by conventional methods and by the automatic instrument with satisfying results.

Adult↗
PubMed1975

An automatic static perimeter, design and pilot study.

An instrument for automatic static perimetry at 14 points across a meridian was constructed and used in a pilot study. The machine was controlled by a computer and the subjects responded to the light stimuli by pressing one of two push-buttons. Most people investigated readily understood the rules at testing. "Blunders" made by the subject were, however, so common, that allowance had to be made in the test programme for a number of mistakes. The test stimuli should be exposed in random order. When the zone of uncertain seeing is wide - this occurs especially in untrained subjects - a simple test logic gives a fairly large variation. An improvement in reproducibility is then obtained by applying a more complicated logic, though at the cost of an increased duration of the test session.

Adult↗