Biomedical subjects

G T Petito

Publications and source records attributed to G T Petito.

6 recordsLinked to original sources

PubMed1991

Fixation disparity: clinical implications and utilization.

Research suggests that fixation disparity data is extremely useful in the assessment of the binocular and accommodative systems. However, clinicians have been slow to integrate this method of analysis into their practices. Fixation disparity measurement, under different fusional and accommodative demands, aids the practitioner in prescribing ophthalmic prism and/or plus lenses. In addition, it helps determine when vision therapy is appropriate and provides an objective assessment of the effectiveness of a vision therapy program. This paper discusses significant aspects of horizontal and vertical fixation disparity measurement, with particular emphasis on its clinical usefulness in understanding and resolving asthenopic symptoms attributable to vergence and/or accommodative dysfunction. The goal of this paper is to provide the practitioner with information so that fixation disparity testing can be incorporated within the clinical regimen.

Accommodation, Ocular↗

PubMed1989

Retinal arterial macroaneurysm: a longitudinal case study.

Retinal arterial macroaneurysms are a relatively rare clinical entity that occur most frequently in the elder female population. They are strongly associated with systemic hypertension. Variable clinical presentations may occur, which may often lead to misdiagnosis. Correct diagnosis is essential for proper follow-up care and potential treatment. Differential diagnosis includes Coats' disease, angiomatosis retinae, Leber's miliary aneurysm, diabetic retinopathy, ectopic neovascular membrane, and malignant melanoma. The importance of the differential diagnosis is exemplified in a case report of a macroaneurysm which, upon initial ophthalmoscopic presentation, was concealed by surrounding retinal hemorrhage. The clinical features, differential diagnosis, management, and treatment of retinal macroaneurysms are discussed.

Aged↗

PubMed1988

A model of spatial localization and its application to strabismus.

Visually guided, spatially oriented behavior involves an ongoing integration of signals regarding the loci of the retinal images and the position and orientation of the eye. In the strabismic this requires an altered spatial metric resulting from a functional readaptation to avoid confusion and diplopia. A comparator mechanism for evaluating these two signals is presented. A case report using "disruptive" therapeutic procedures that deliberately alter the strabismic's visual-postural control system is presented. A treatment plan for altering the anomalous binocular link, a characteristic of the well adapted strabismic, is described and related to the comparator mechanism.

Adaptation, Physiological↗

PubMed1986

Nonlinear forced vertical vergence fixation disparity curves and their clinical significance.

Two examples of nonlinear, forced vertical vergence, fixation disparity curves are presented. These curves have a flattened portion similar to the sigmoid forced horizontal vergence fixation disparity curve described as "type I". The existence of sigmoid, forced vertical vergence, fixation disparity curves suggests that the horizontal and vertical vergence mechanisms may operate in similar fashion. Possible clinical implications of this finding relative to prismatic prescriptions for vertical vergence anomalies are also discussed.

Adaptation, Physiological↗

PubMed1986

The efficacy of visual therapy: accommodative disorders and non-strabismic anomalies of binocular vision.

Questions concerning the effectiveness of therapeutic intervention designed to modify the function of an individual's visual system have been raised by professional groups, consumer groups, insurance carriers, students, educators, as well as "pure" scientists. This paper examines the available literature in order to answer the question, "Is there evidence that 'orthoptics' or 'vision therapy' causes changes in an individual's accommodative or vergence eye movement systems?" This review neither examines alternative methods of causing these changes nor provides information concerning which particular techniques are most effective, although the literature does provide such information. Certain conditions are explained to aid the student and lay-reader in understanding the literature cited. The literature cited substantiates that visual therapy can modify visual functions and also points out the relationship of these changes to the relief of certain symptoms.

Accommodation, Ocular↗

PubMed1984

Broken wheel acuity test: a new and valid test for preschool and exceptional children.

This study describes a new visual acuity test for preschool and exceptional children. It is independent of verbal responses, uses a forced-choice testing procedure, incorporates the psychometric design advantages of the Landolt ring, and can be administered at 3m (10 ft) in 5 to 7 minutes. The results support its construct validity in accurately measuring visual acuity levels and its clinical applicability for preschool and exceptional children.

Child↗