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B C Reeves

Publications and source records attributed to B C Reeves.

13 recordsLinked to original sources
PubMed1994

Effectiveness of unsupervised oculokinetic perimetry for detecting glaucomatous visual field defects.

Oculokinetic perimetry (OKP) is a simple, inexpensive technique which was introduced primarily to promote more widespread use of visual field screening for glaucoma. The effectiveness of unsupervised OKP screening was evaluated using 145 non-glaucomatous patients and 64 patients with previously undiagnosed primary open angle glaucoma. Glaucoma cases were validated by the extended 132 point program on the Henson CFS2000 instrument. Both sample populations were representative of patients presenting for primary vision care. The effectiveness of the 26 point OKP test was compared with the 26 point Henson screening program. The results suggest that, in contrast to the Henson screening test (sensitivity = 85.1%, specificity = 93.8%), unsupervised OKP screening (sensitivity = 25.0%, specificity = 93.6%) has limited effectiveness for detecting glaucomatous visual field defects.

Adult↗
PubMed1992

Visual recovery using small dilating eye drops.

It is well established that reduced size dilating eye drops of 1% tropicamide and 10% phenylephrine (micro drops) are effective for clinical purposes. Excellent pupil dilatation (mydriasis) is achieved and pupil constriction does not occur in response to light. In this study, the effect of micro drops of 1% tropicamide on distance and near visual recovery was compared with standard drops in a group of 20 healthy volunteers. For each person studied, one eye was selected at random to be tested first with the standard drop size, and then after a minimum of one week, the same eye was again tested using a drop of the same drug one fifth standard size. An iris photograph, Snellen visual acuity at 6 m, and reading visual acuity was obtained for each test procedure: before drop instillation and at 30 min, 1, 2 and 4 h after drug instillation. Use of the micro drops caused a small but statistically significant improvement in the rate of recovery of distance and near visual acuity. These findings, allied to the known beneficial effects of reduced systemic absorption using micro drops, lend further weight to the argument that mydriasis may be achieved more safely, with fewer side effects, and with earlier return of normal vision when reduced size drops are used. It is hoped that practical micro drop dispensers will be developed.

Adult↗
PubMed1992

Evaluation of two infrared autorefractors in pseudophakia.

We investigated the viability of using an objective infrared autorefractor to identify high corneal astigmatism (> 3.00 D) in a pseudophakic population. The eyes of 91 patients, who had recently undergone cataract extraction and intraocular lens implanation, were refracted manually and using two infrared autorefractors, a Canon RK-1 and a Nikon NR-2000. Autorefractor measurements were repeated to provide estimates of reliability for each instrument. LogMAR visual acuities were also recorded with both the manual and autorefractor corrections. Approximately 75% of repeat autorefractor measurements were within 0.50 D of the initial readings, and about 75% of measurements were within 1.00 D of the manual refractions. Visual acuities with manual corrections were, on average, one line better than with autorefractor corrections. By validating the autorefractors against manual refraction, the efficiency of the autorefractors for detecting astigmatism > 3.00 D was calculated. Setting the cut-off criterion to ensure high sensitivity (95%), so that almost all patients with > 3.00 D were detected, resulted in both instruments having a poor specificity of about 40%.

Adult↗
PubMed1991

Vistech VCTS 6500 charts--within- and between-session reliability.

The aim of the study was to measure the reliability of the Vistech VCTS 6500 charts, in test score units, in order to allow clinicians to derive estimates of what constitutes a clinically meaningful change in performance over time. The reliability of a more familiar test, Bailey-Lovie high contrast visual acuity, was also measured to provide a comparison. Patients with normal vision and with early or subtle eye disease were recruited so that the results would be representative of the population likely to present for primary vision screening. Patients were tested on all three VCTS charts on two separate occasions at least 3 weeks apart to give estimates of within- and between-session reliability. Reliability was found to be low in all circumstances; between-session reliability could be improved by using the mean score for the three charts, but the 95% range of difference scores still encompassed at least one-half of the total performance range of the test. It was concluded that Vistech charts are unlikely to be of use for clinical measurements or for research studies.

Adult↗
PubMed1988

Huematic--an automated scorer for the Farnsworth-Munsell 100 hue test.

A cheap, portable automated scorer for the Farnsworth-Munsell (FM) 100 hue test has been developed. It consists of a light pen, a series of omni-directional bar-codes attached to the reverse of the FM 100 hue caps and a small micro-computer. The print-out includes patient details, a linear histogram of the partial errors by cap position, indication of the peak error positions for congenital colour vision deficiencies and appropriate statistical analysis of the total error score. All the results are available within four minutes of completing the testing procedure.

Adolescent↗
PubMed1988

Test-retest reliability of the Arden Grating Test: inter-tester variability.

The aim of this study was to investigate the test-retest reliability of the Arden Grating Test (AGT), and to assess the extent to which any variance in AGT score on retest can be attributed to intra-subject and inter-tester differences. Twelve patients with various pathologies and whose contrast sensitivity covered a wide range were each tested twice by six testers. It was shown that variance attributable to testing by different clinicians accounted for approximately 25% of the total variance, and that the 95% confidence limits about any observed score were +/- 15 AGT units, which is about one quarter of the total dynamic range of the test. The large range of scores encompassed by the 95% confidence limits represents considerable unreliability, the consequence of which is a high misclassification rate, i.e. many false positives and false negatives, especially in the context of primary vision screening for which it was designed.

Adult↗
PubMed1987

Myopia and cataract.

Explore the source record for details and available documents.

Analysis of Variance↗
PubMed1987

The clinical significance of change.

Clinicians frequently make judgements about the clinical importance of a change in "score" on visual function tests obtained from patients on successive visits. Almost no normative data for assessing the significance of change in performance on routinely used clinical tests exists, and the importance of collecting such data is emphasized. A description of how normative data for the significance of change can be collected is given, using the Farnsworth-Munsell 100 hue test as an example. Although there are always limitations to estimates of error variance, the importance of determining the precision of clinical tests, for guiding rational decision making, is stressed.

Adult↗
PubMed1985

Detection of optic nerve damage in ocular hypertension.

Thirty patients with ocular hypertension were tested for contrast sensitivity loss. Seventeen were not on treatment, and thirteen were receiving some form of pressure reducing therapy. The contrast sensitivity results of 63% of ocular hypertensive eyes were abnormal (greater than 2 SDs from the age matched norm). Thus it appears that contrast sensitivity can detect early visual loss in patients who have normal visual fields and it is suggested that this test might be used as a criterion for therapy in ocular hypertension. There was no significant difference in the intraocular pressures between patients who gave abnormal contrast sensitivity results and those who did not in the untreated group (p greater than 0.05), suggesting that intraocular pressure level is a poor predictor of optic nerve fibre damage in patients with ocular hypertension.

Aged↗