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Biomedical subjects

M H Birnbaum

Publications and source records attributed to M H Birnbaum.

At least 37 records · Page 2Linked to original sources
PubMed1984

Nearpoint visual stress: a physiological model.

The nearpoint visual stress theory holds that a tendency for convergence to localize closer than accommodation is intrinsic to the nearpoint visual demands imposed by our culture. A physiological model is presented, suggesting that this effector system mismatch arises from the activation of autonomic reflexes related to stress, vigilant attention and information-processing. Autonomic arousal exerts a cycloplegic-like effect. Excess accommodative effort, which must be exerted to achieve required accommodation, produces a tendency towards overconvergence. The demand for integration of accommodation and convergence, essential for efficient nearpoint function, is thus incompatible with our own physiology, since autonomic arousal is inherent in task demands for attention and mental effort associated with reading. Additionally, autonomic arousal is generated by the high levels of stress pervasive in our society. Various refractive, binocular and accommodative deviations may arise adaptively in order to resolve this mismatch and facilitate efficient nearpoint visual function. These nearpoint stress-induced visual disorders parallel stress-induced systemic illness in that both result from the activation of physiological processes which are inappropriate for the demands and stresses of our society.

Accommodation, Ocular↗
PubMed1984

The power of visual training.

Recent evidence suggests that the capacity to alter human function, including visual function, is substantially greater than previously thought possible. Implications of this research for the modifiability of visual function through vision therapy are discussed.

Accommodation, Ocular↗
PubMed1982

Loci of contextual effects in judgment.

Three experiments investigated the loci of contextual effects in judgment. Experiment 1 demonstrated the effect of stimulus spacing on category ratings and magnitude estimations of the darkness of dot patterns. Variations in the stimulus spacing were shown to affect both category ratings and magnitude estimations in a similar fashion. Experiment 2 was designed to determine whether contextual effects due to stimulus spacing influence the scale values or the judgment function. Subjects judged "differences" and "ratios" of the subjective darkness of dot patterns. Differences in mean judgments of single stimuli from Experiment 1 did not predict the rank order of judged "differences" and "ratios" from Experiment 2. The estimated scale values of the stimuli appeared to be independent of stimulus spacing. These findings suggest that contextual effects due to the stimulus spacing occur in the judgment function for within-modality judgments. Experiment 3 examined contextual effects in cross-modality judgments. Stimulus spacing and stimulus range were manipulated for "difference" and "total" judgments. Unlike the within-modality results, the stimulus range and spacing influenced the scale values. A contextual theory of within- and cross-modality judgment is presented.

Discrimination Learning↗
PubMed1981

Clinical management of myopia.

The literature indicates that environmental factors, particularly those related to nearwork, play a significant role in myopia etiology. Regimens are described for the clinical management of myopia in the incipient, progressive, and stable stages. These regimens are based upon control of the environmental factors producing myopic progression and include the use of bifocal lenses to reduce accommodative demand, advice concerning visual hygiene to foster accommodative relaxation, and vision training to develop adequate accommodative skills and adequate freedom of action between the systems of accommodation and convergence.

Accommodation, Ocular↗
PubMed1981

Esotropia, exotropia and cognitive/perceptual style.

In order to assess differences in cognitive/perceptual style between esotropes and exotropes, the Childrens' Embedded Figures Test was administered to a sample of young male and female strabismics. Significant differences in performance were found among the male subjects, indicating a tendency for esotropes to demonstrate a more analytical, highly differentiated style than do exotropes. These differences were not found among females, perhaps related to differences in the nature of cerebral hemispheric specialization.

Child↗
PubMed1980

Comparison of two theories of "ratio" and "difference" judgments.

This article examines the hypothesis that judges compare stimuli by ratio and subtractive operations when instructed to judge" "ratios" and "differences." Rule and Curtis hold that magnitude estimations are a power function of subjective values, with an exponent between 1.1 and 2.1. Accordingly, the two-operation model tested assumes magnitude estimations of "ratios" are a comparable power function of subjective ratios. In contrast, Birnbaum and Veit theorize that judges compare two stimuli by subraction for both "ratio" and "difference" instructions and that magnitude estimations of "ratios" are approximately an exponential function of subjective differences. Three tests were used to compare the theory of one operation with the two-operation theory for the data of nine experiments. The results strongly favor the theory that observers use the same operation for both instructions.

Discrimination Learning↗
PubMed1979

Management of the low myopia pediatric patient.

A review of the literature on myopia etiology indicates that environmental factors, particularly those related to nearpoint use of the eyes, appear to play a significant role. A regimen is described for control of environmental factors producing myopic progression, including use of bifocal lenses to reduce accomodative demand, visual hygiene to foster accommodative relaxation, and vision training to develop adequate accommodative skills and freedom of action between accommodative and convergence systems.

Accommodation, Ocular↗
PubMed1978

Holistic aspects of visual style: a hemispheric model with implications for vision therapy.

A model is proposed relating styles of cognition and perception, modes of consciousness, and cerebral hemispheric function to visual styles and visual problems. The implications of such a model for management of vision problems are discussed. It is recommended that training for the central, eso patient emphasize procedures which are spatial, holistic, peripheral, simultaneous, and involve the use of imagery. For the peripheral, exo patient, treatment techniques should involve sequence and rhythm, analytical processing, discrimination of fine differences, and attention to detail in central areas of the visual field.

Child↗
PubMed1978

Functional relationship between myopia, accommodative stress and against-the-rule astigmia: a hypothesis.

A model is proposed to explain the well-established tendency for against-the-rule astigmatism to precede and be predictive of the later development of myopia. It is hypothesized that the against-the-rule astigmatism is a functional adaptation to reduce near point stress by permitting reduced accommodative output (increased lag of accommodation) while maintaining resolution for the primarily vertically-oriented characters of the English language.

Accommodation, Ocular↗
PubMed1977

The role of the trainer in visual training.

The role of the trainer in assisting the patient to internalize changes in his visual process is discussed. Emphasis is placed on two aspects: (1) making the patient aware of the nature of the change in process desired, and (2) making the patient aware that the phenomena which he observes during vision training techniques, such as blurring and clearing, diplopia, and suppression of training targets, which he may perceive as occurring esternally reflections of his visual process and as such, are subject to his control.

Child↗
PubMed1977

Success in ambylopia therapy as a function of age: a literature survey.

It is frequently stated that amblyopia is not correctable after the age of 6 years. Many practitioners report marked success for older patients. To evaluate these conflicting reports, we analyzed the results from 23 published amblyopia studies. Our analysis indicates that substantial numbers of patients over age 6 were successfully treated. Success rates under age 6 were not significantly better than those in older patients when the criterion for success was achievement of 20/30 acuity or better. When a criterion of 4 lines improvement was used, success rates at all ages under 16 were quite similar; in patients 16 and over, success by this criterion was significantly less frequent, but even in this group success was achieved by 42% of the patients.

Adolescent↗
PubMed1976

Adverse response to prism therapy in strabismus.

The recent literature on prism therapy in strabismus is reviewed. A case is reported in which an esotrope, treated by means of prism neutralization to effect sensory orthotropia, responded with a marked increase in the angle of squint. Guidelines are suggested to minimize risk of such adverse effect when prism therapy is attempted.

Child↗