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Biomedical subjects

K M Daum

Publications and source records attributed to K M Daum.

At least 37 records · Page 2Linked to original sources
PubMed1986

Characteristics of exodeviations: I. A comparison of three classes.

A retrospective study of 179 patients (69 males and 110 females) with binocular visual dysfunction and an exodeviation at distance or near or at both distances has been completed. The mean age of 19.7 years was significantly younger than the population from which they were referred. The patients were classed as convergence insufficiency, equal exodeviation, or divergence excess, based on the relation of the distance and near angles of deviation. Based on these criteria, interaction was found to be present between the diagnostic class and the frequency of the deviation, the symptoms reported, and a variety of clinical parameters such as the angles of deviation at distance and near, the AC/A ratio, positive and negative vergence values, the amplitude of accommodation, and the threshold of stereopsis. A number of statistical relations were noted between the frequency of the deviation vs. the symptoms reported and a variety of the clinical parameters. The implications of these results are discussed.

Accommodation, Ocular↗
PubMed1986

Characteristics of exodeviations: II. Changes with treatment with orthoptics.

This study examined retrospectively the records of 179 patients who had binocular visual dysfunction as a result of an exodeviation (either at distance or near or both). The patients were classified as having convergence insufficiency (N = 110), equal exodeviations (N = 49), or divergence excess (N = 18). The diagnostic groups and the different frequencies of deviation reacted differently to treatment with a standard orthoptic regimen. Nearly all the patients (97%) achieved some improvement in either objective or subjective areas or both. However, fewer were able to satisfy the criteria set for total success. Factors correlated with the success of the treatment were the initial angle of deviation at distance and the initial level of stereopsis. The results and implications of this study are discussed.

Adolescent↗
PubMed1986

The use of progressive addition multifocals with video display terminals.

Consideration must be given to a number of factors when designing spectacles for the presbyopic VDT worker. Video terminals are routinely positioned high within the working field, usually at an intermediate distance. It is often difficult for a practitioner to design a single pair of multifocals to satisfy the visual needs of these workers. In this investigation, different fitting designs of progressive addition multifocals were subjectively compared for 24 presbyopic VDT operators. The results were correlated with measurements taken at the workstations for each of the participants.

Computer Systems↗
PubMed1984

Classification criterion for success in the treatment of convergence insufficiency.

Using data collected from a retrospective study of the records of 110 patients diagnosed as having convergence insufficiency, a model has been developed which allows the classification of a patient into one of two categories of success (total or partial/none) on the basis of an initial examination. The subjects were treated with orthoptics and classified into either the total success group (no objective or subjective visual difficulties) or the partial/no success group. Stepwise discriminant analysis was used in the data reduction phase in which 6 of 14 possible variables were selected which best explained the variation in the degree of success. These six variables were: (1) the AC/A ratio; (2) the negative vergence blur value at 40 cm; (3) the recovery value of the positive vergences at 6 m; (4) the break value of the positive vergence at 6 m; (5) the amplitude of accommodation; and (6) the frequency of the deviation. Subjects were more likely to be successful when 1, 2 and 3 were high, 4 and 5 were low, and the deviation was latent. Discriminant analysis using these six variables allowed 25 of 33 (76%) of the patients to be correctly classified in terms of their success. The application of the model for classifying patients with convergence insufficiency is presented and briefly discussed.

Accommodation, Ocular↗
PubMed1984

Convergence insufficiency.

A retrospective study of 110 subjects with convergence insufficiency has been completed. Their mean age was 19.9 years. There were 72 females and 38 males in the group. The clinical profiles of these subjects were examined before and after a standard orthoptic treatment regimen. Over the course of treatment, the near angle of deviation, the AC/A ratio, a portion of the negative vergence values, all the positive vergence values, the nearpoint of convergence, and the amplitude of accommodation were found to have changed in a statistically significant manner. The importance of these findings is discussed.

Accommodation, Ocular↗
PubMed1984

Predicting results in the orthoptic treatment of accommodative dysfunction.

A retrospective analysis of the records of 114 orthoptic patients diagnosed as having accommodative dysfunction (accommodative insufficiency, fatigue of accommodation, infacility of accommodation, or spasm of accommodation) has allowed the construction of models of the results of orthoptic treatment. Discriminant analysis completed on various samples of the group provides linearized discriminant functions for the success of the treatment (either total or partial/none) and for the change in accommodative amplitude. These data indicate that linearized discriminant functions using the age and AC/A ratio of the patient are effective in postpredicting the success category of 60% of a calibration sample of 99 patients. Similar functions using the patient's age, initial accommodative amplitude, and blur value of the near positive vergences allow the postprediction of the category of change in accommodative amplitude with treatment (3 D or more vs. 2 D or less). Seventy-eight percent of a sample of 68 patients were correctly classified. The application of these models in predicting the results of treatment of similarly afflicted subjects is discussed.

Accommodation, Ocular↗
PubMed1984

Human tears: glucose instabilities.

Using a photometric method, a comparative analysis based on 717 human tear samples was made between systematically collected non-reflex, open eye tears and tears associated with prolonged eye closure (sleep), as well as for certain reflex provoking conditions (mild mechanical irritation, irritating vapours and osmotic imbalance). Although the closed eye tear glucose mean for the 8 young adults studied was found to be less than their open eye mean (5.01 versus 7.50 mg%), those two values were not found to be significantly different. However, statistical comparisons made between non-reflex open eye tears and the mechanical, irritating vapour and osmotic responses were found to be different at the P less than 0.05 level of significance, a higher mean concentration being found for the mechanical and osmotic conditions, and a lower mean concentration for the vapour induced condition.

Adult↗
PubMed1984

Human tears: glucose instabilities.

Using a photometric method, a comparative analysis based on 717 human tear samples was made between systematically collected non-reflex, open eye tears and tears associated with prolonged eye closure (sleep), as well as for certain reflex provoking conditions (mild mechanical irritation, irritating vapours and osmotic imbalance). Although the closed eye tear glucose mean for the 8 young adults studied was found to be less that their open eye mean (5.01 versus 7.00 mg%), those 2 values were not found to be significantly different. However, statistical comparisons made between non-reflex open eye tears and the mechanical, irritating vapour and osmotic responses were found to be different at the P less than 0.05 level of significance, a higher mean concentration being found for the mechanical and osmotic conditions, and a lower mean concentration of the vapour induced condition.

Adult↗
PubMed1984

Divergence excess: characteristics and results of treatment with orthoptics.

This paper retrospectively examines the results of the treatment of 18 subjects (11 males, seven females) with divergence excess, using orthoptics. The mean age of the subjects was 15.8 years, which was significantly younger than the population from which this group was referred. Diplopia (89%) and asthenopia (56%) were the most frequently reported symptoms. Seventy-two per cent of the subjects had intermittent deviations of the eyes. Over the mean necessary course of treatment of 5.2 weeks, the distance angle of deviation (slightly) and the positive vergences at distance and near were found to have changed significantly. The near angle of deviation, the negative vergences, the near point of convergence, the amplitude of accommodation, and the threshold of stereopsis were found to have remained stable over the treatment period. Further results of the study are presented and the implications of these results with regard to the treatment of divergence excess are briefly discussed.

Adolescent↗
PubMed1984

Modelling the results of the orthoptic treatment of divergence excess.

Using data compiled from an earlier study of the results of the orthoptic treatment of divergence excess [Daum, K. M. Ophthal. Physiol. Opt. 4, 15-24 (1984)], a model has been presented regarding the results of the treatment. Provided the calibration sample is representative, the model may be used after an initial examination to predict the class of success a given subject will eventually be placed in as a result of orthoptic treatment. After treatment with a standard orthoptic regimen, the subjects were classified as being either totally successful (no objective or subjective visual difficulties) or partially/not successful. Stepwise discriminate analysis of 15 independent variables for the dependent variable success was used in order to choose the model with the highest coefficient of determination (r2) and the best statistical significance. The three variables chosen for the model were the angle of deviation at near and the blur and break values of the negative vergences at near. Using these variables, discriminant analysis was performed on the calibration sample of nine subjects. Each was classified correctly. The use and limitations of the model are briefly discussed.

Adolescent↗
PubMed1983

Accommodative dysfunction.

A retrospective review of the records of 114 subjects with accommodative dysfunction has been completed. Most subjects (N = 96) were found to have accommodative insufficiency. Lesser numbers of subjects were categorized in the class of infacility of accommodation (N = 14), spasm of accommodation (N = 3) and fatigue of accommodation (N = 1). A majority of the subjects presented with complaints of blur, headaches and/or asthenopia while attempting nearwork. Most subjects presented with reduced abilities in one or more of the following areas: accommodative amplitude and facility, fusional vergences, near point of convergence and stereo acuities. The clinical characteristics of the group as a whole and the major subgroups have been examined both before and after treatment of the condition with orthoptic exercises and/or plus lenses at the nearpoint. The result of the treatment indicates that although most subjects (96%) experienced some relief with treatment only about half (53%) had their problems totally solved. The importance of these findings is briefly discussed.

Accommodation, Ocular↗
PubMed1983

Analysis of seven methods of measuring the angle of deviation.

The correlations between seven methods of measuring the angle of deviation were assessed in two groups of subjects. Group 1 consisted of 343 subjects with normal binocular vision. Group 2 was made up of 18 subjects with strabismus. The correlation coefficients (r) between various testing procedures varied significantly in the two groups. Group 1 could be separated into three levels of correlation and group 2 could be separated into two levels of correlation based on the 95% confidence limits of the correlation coefficients. Significant differences also could be demonstrated in the average measured values of the angle of deviation of group 1, while the second group was indistinguishable at the 5% significance level using a one-way analysis of variance procedure. These data are briefly discussed in light of their clinical implications.

Adult↗
PubMed1983

Characteristics of a video-type pupillometer.

In using a video-type pupillometer, the adjustment of the clipping level, the illumination of the target, the focus of the camera, and the viewing angle have been shown to affect the measurement. The focus of the camera and the viewing angle are the most important variables. The precision of this instrument can be as good as 0.01 mm. The accuracy of the instrument is good with regard to clinical standards; however, all measurements vary slightly from the known value. Interexaminer variation appears to be small.

Computers↗
PubMed1983

Accommodative insufficiency.

A retrospective review of the records of 96 patients with accommodative insufficiency has been completed. In addition to the major sign of reduced accommodative amplitude for their ages, I often found a reduction in the facility of accommodation, a smaller lag of accommodation, a tendency toward convergence insufficiency, slightly reduced fusional vergence and stereopsis, and a reduced nearpoint of convergence. Suppression was not generally found. The results of orthoptic exercises and/or a plus lens addition at near were examined. Most patients (90%) obtained some relief with treatment. About 53% had their objective and subjective problems totally solved during an average treatment period of 3.7 weeks. I determined the characteristics of the patients before and after treatment. The current state of the treatment of accommodative insufficiency is discussed.

Accommodation, Ocular↗
PubMed1983

A comparison of the results of tonic and phasic vergence training.

Thirty-four healthy asymptomatic young adults were randomly divided into two groups. All subjects underwent training aimed at expanding the vergence ranges. The training in one group consisted of tasks emphasizing smooth, slow activities. The other group trained using quicker, stepwise, more phasic tasks. The vergence ranges were subjectively measured using a small (1.72 degree diameter) target in a major amblyoscope. The study lasted 6 weeks. The first 3 weeks served as a control period over which time the vergences proved to be stable. The training was done for 10 min on the weekdays of the last 3 weeks of the study. Analysis of the data indicates that the group training via the stepwise or phasic paradigm showed greater increases in both the positive and negative vergences. Both groups achieved substantial increases in both the negative and positive vergences. The significance of these results is discussed.

Adult↗
PubMed1982

Pupillary micro movements apparently related to pulse frequency.

Pupillary micro changes in diameter apparently related to pulse frequency are superimposed on the larger fluctuations called the pupillary unrest. This small component of the pupillary unrest waxes and wanes with each pulsation of the blood. The effect was found to vary inversely with the average pupil diameter which can be controlled by making the eye accommodate or allowing more or less light to enter the eye.

Accommodation, Ocular↗
PubMed1982

Covariation in anomalous correspondence with accommodative vergence.

In a patient with constant concomitant alternating exotropia at distance and near, the angle of anomaly varied in concert with the objective angle as the objective angle was altered by stimulating accommodative convergence using concave lenses to stimulate accommodation. The angle of anomaly was found to vary up to 31 delta as the objective angle was varied up to 37 delta. The correlation coefficient (r) between the two variables was 1.00. The implications of this finding are discussed.

Accommodation, Ocular↗