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Biomedical subjects

B Coffey

Publications and source records attributed to B Coffey.

9 recordsLinked to original sources

Treatment options in intermittent exotropia: a critical appraisal.

Clinical opinions regarding treatment of intermittent exotropia (IXT) vary widely and there is controversy as to which treatment modality is most successful. This paper reviews the clinical literature related to five different treatment modalities used for IXT: overminus lens therapy, prism therapy, occlusion therapy, extraocular muscle surgery, and orthoptic vision therapy. Based upon review of 59 studies of treatment of IXT, and using each author's stated criteria for success, the following pooled success rates were revealed: over-minus lens therapy (N = 215), 28%; prism therapy (N = 201), 28%; occlusion therapy (N = 170), 37%; extraocular muscle surgery (N = 2530), 46%; and orthoptic vision therapy (N = 740), 59%. Success rates for IXT surgery differed depending upon whether a functional (43%) or cosmetic (61%) criterion was used to evaluate treatment success. These pooled success rates must be viewed carefully because nearly all the studies suffer from serious scientific flaws such as small sample sizes, selection bias, inadequately defined treatments and success criteria, absence of statistical analysis, and results reported in a manner that makes interpretation difficult. These problems indicate the need for a careful, circumscribed, and well controlled clinical trial to study the efficacy of different treatment modalities in remediating IXT.

Contact Lenses

Binocular vision section.

The participants at the 1991 Meetings of the Section on Binocular Vision and Perception presented a substantial amount of valuable theoretical and clinical information. There was considerable and valuable interaction between the audience and panel, especially after the symposium concerned with new techniques and how to use them. The exchange of specialized knowledge through discussions at symposiums such as these represents one of the best features of Academy meetings. These symposiums reemphasize and remind us of the expertise of our Academy members in management of binocular vision anomalies.

Dyslexia

Effects of disinfecting solutions recommended by the Centers for Disease Control on Goldmann tonometer biprisms.

Twelve new Goldmann biprisms were used to measure the intraocular pressure of one eye of one subject, four times each day for 15 days. Between measurements, each biprism was disinfected by soaking in one of the three solutions recommended by the Centers for Disease Control (CDC) as effective against HIV, or by rubbing with an isopropyl alcohol swab. Intraocular pressure measurements, clarity of the biprism front surface, and ring image were statistically evaluated to determine whether any regimen negatively affected the biprisms. Biprisms soaked in alcohol were unusable after 4 days due to front surface roughness. No clinically significant differences were found in IOP measurements or clarity of the remaining groups, but the ring image was significantly less distorted with hydrogen peroxide treatment. These results suggest that hydrogen peroxide should be used to disinfect Goldmann biprisms.

1-Propanol

Relationship of clinical severity to packed cell rheology in sickle cell anemia.

There is wide variation in the clinical manifestations of sickle cell disease (SCD) from one affected individual to another. Many investigators have sought to discern parameters that would explain this variability. In the present studies we have attempted to correlate the frequency of painful events and the extent of end organ failure in SCD with rheologic properties of packed suspensions of sickle cells, using a magneto-acoustic ball microrheometer developed in our laboratory. Using this device we have measured the steady-state viscosity, and the viscous and elastic moduli of cell suspensions in 16 individuals with hemoglobin SS disease who were untransfused and in their steady state. The rheologic parameters were then correlated with clinical parameters. The clinical parameters measured were emergency department visits, hospitalizations, hemoglobin, reticulocyte count, age, and end organ failure (nephropathy, avascular necrosis of bone, stroke, retinopathy, resting hypoxemia after acute chest syndrome(s), leg ulcer, and priapism with impotence). The P value for the correlation between the steady state viscosity and end organ failure was .001 with a correlation coefficient (R value) of .73. The P value for the correlation between the viscous modulus of viscosity and end organ failure was .00006 with an R value of .83. The P value for the correlation between the elastic modulus of viscosity and end organ failure was .0006 with an R value of .76. However, there was no significant correlation between any component of packed cell rheology and emergency department visits or hospitalizations for pain.

Adult

Influence of ocular gaze and head position on 4 m heterophoria and fixation disparity.

Four-meter heterophoria and fixation disparity measurements were taken from a sample of 40 young adults in primary gaze, 33 degrees left and right lateral gaze, and in 2 head/gaze positions related to golf putting. Comparisons using analysis of variance were made between the mean values in each gaze position and between the test-retest range of values in each gaze position. Mean heterophoria was more eso (p less than 0.05) in the two head/gaze positions related to golf putting than in other gaze positions, whereas mean fixation disparity was more eso (p less than 0.05) in rightward than in primary gaze. Phoria test-retest range was less (p less than 0.05) in all nonprimary gaze positions than in primary gaze. One of the putting-related gaze positions showed smaller (p less than 0.05) fixation disparity ranges than the primary or leftward position of gaze. All measures were highly variable among subjects. Trends present in the data suggested greater esophoria and eso fixation disparity mean values, and lesser heterophoria and fixation disparity test-retest range values in all nonprimary positions relative to primary gaze. The behavior of exophoric and esophoric subjects differed only in regard to changes in heterophoria associated with left and right lateral gaze. These data indicate differences in oculomotor postural tendencies relative to position of gaze. Relevance of the results to athletes is discussed.

Adult

Pain insensitivity in schizophrenia. Case report and review of the literature.

We describe a schizophrenic man whose lack of pain and related objective signs of a perforated small bowel led to a delay in diagnosis and surgical intervention. A review of the literature suggests that both psychodynamic and specific biologic factors can produce atypical presentations in psychotic patients with illnesses in which pain is characteristically a prominent presenting symptom. While research into the cause of altered pain perception in psychotic patients is continuing, clinicians should maintain a high index of suspicion of serious medical illness when evaluating such patients.

Abdomen, Acute

Comparison of Snellen letter and Vistech grating charts as refraction targets.

Snellen letter and Vistech sine wave grating charts were used as refraction targets to determine differences in times required to accomplish subjective refractions, endpoint refractive values, and subject preferences. Thirty hyperopes and 30 myopes, divided into three age groups, were selected as subjects. Two examiners tested each subject using each chart. Both timed their subjective refractions and recorded their findings. After all data were recorded, each subject completed a questionnaire to determine chart preference. There were no clinically significant mean differences between the charts in terms of endpoint refractive data, but, on average, the Snellen chart was faster to use. Chart rating depended on the subject's refractive status with more myopes preferring the Snellen chart and more hyperopes rating the grating chart higher.

Adolescent