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Biomedical subjects

J Daubs

Publications and source records attributed to J Daubs.

11 recordsLinked to original sources
PubMed1983

Application of visual signal detection concepts to clinical decision analysis.

The performance of both clinical diagnostic and mass screening tests is commonly measured in terms of the two basic parameters, sensitivity and specificity. Selection of cut-off points, balancing the sensitivity-specificity trade-off, and comparison with alternative tests are often a matter of arbitrary decisions and are frequently made without consideration of outcome. Some of the concepts used in the analysis of visual signal detection systems can be helpful in this aspect of screening test selection and evaluation. A simplified version of these concepts is developed and its application to clinical and public health optometry is illustrated.

Cost-Benefit Analysis↗
PubMed1983

Optical prophylaxis for environmental myopia: an epidemiological assessment of short-term effects.

The biologically plausible concept that relief of accommodation may reduce myopic progression, although not confirmed and not universally accepted, has nevertheless strongly influenced the practice of preventive optometry. Yet, no quantitative estimates of the strength of this postulated effect were found in the literature. From a cohort study of 120 young (18 to 20 years of age) male military students with low initial refractive error (less than or equal to +/- 1D, spherical equivalent), estimates were made of the short-term (5 months) effect of two forms of optical treatment to prevent school-related myopia. The cumulative incidence of clinically significant (greater than 0.25 D, spherical equivalent) myopic progression was less [standardized morbidity ratio (SMR) = 0.45] among those prescribed monofocal convex lenses (+1.25 D over far Rx) and prisms (2 delta base-in OU) and even more reduced (SMR = 0.32) among those prescribed bifocals (+1.5 D near adds) compared with those receiving sham treatment (no. 1 pink tint). Placebo-treated patients were more than twice [rate ratio (RR) = 2.2, 1.5] as likely as the monofocal group, and more than three times (RR = 3.2, 1.7) as likely as the bifocal patients, to suffer myopic progression during the period of follow-up. Etiologic fractions (EF, increase in myopic progression if treatment were eliminated) of 37 and 47% and preventive fractions (PF, decrease in myopic progression attributable to the treatment) of 27 and 32% were estimated for the monofocal and bifocal treatments, respectively. These findings suggest that while both modes of therapy are efficacious, the bifocal form is 20% (32/27 = 1.2) more preventive.

Adolescent↗
PubMed1982

Environmental factors in the epidemiology of malignant myopia.

Malignant myopia is a major cause of blindness, yet compared with cataract, glaucoma, or diabetic retinopathy, this condition has received little attention from clinical investigators. This study explores existing health and geophysical records in search of clues that might suggest directions for further research into the etiology of blinding myopia. From the environmental data available for analysis, annual hours of sunshine emerged as the factor with the strongest (inverse) association with malignant myopia. Using data from the 14-state Model Reporting Area for Blindness, a case-referent study of this factor revealed both sex and age-birth year modifications of this effect. Relatively more blindness due to malignant myopia occurred among women in low sunshine regions and among men in high sunshine regions. The effect among women appeared during middle age (45 +, or born before 1926) but among men was not seen until later (age 65 + or born before 1906).

Adult↗
PubMed1980

Flight crew exposure to ozone concentrations affecting the visual system.

To estimate the potential for ozone (O3) effects on the human visual system in flight, O3 concentrations in Boeing 747-100 cockpits were measured during routine flights between London and the United States. From a review of previous reports, it appears that O3 may have both beneficial and harmful effects but that further studies of the visual system responses to O3 are needed before the present findings of 0.030 parts per million (ppm) mean O3, 0.200 ppm maximum O3, and 0.261 ppm-hours average cumulative O3 exposure can be effectively evaluated. Unexpectedly high O3 concentrations were encountered at altitudes below 18,000 feet and, at times, the O3 concentration was observed to decrease as flight level was increased. The clinical, operational, and policy implications of these findings are discussed.

Aerospace Medicine↗
PubMed1980

A survey of biostatistics in clinical journals.

A survey of selected journals revealed that use of biostatistics procedures is a common practice in clinical writing. Most of the procedures used could be explained in an introductory coverage of statistics, yet, clinicians rarely show an interest in this subject. Mysterious, misused, and by no means the major matter in clinically pertinent research, statistics is often required but seldom admired.

Medicine↗
PubMed1980

Management of the exceptional presbyope.

Presbyopia, like many age related conditions, does not present an identical picture in all patients. Most, but not all, presbyopes can be cared for satisfactorily by the use of conventional optometric corrections. Some atypical presbyopic patients, however, may benefit from the unorthodox remedial procedures mentioned in this paper.

Age Factors↗
PubMed1976

Epidemiological considerations in predicting regional vision health care needs.

The use of crude practitioner to population ratios when age-specific ratios are more appropriate can lead to significant errors in estimates of the need for health care manpower. A comparison of these 2 methods is made using age-specific data for Florida as an example. A brief survey of other epidemiological factors affecting clinical manpower projections is given.

Adolescent↗
PubMed1976

A retrospective analysis of the systolic BP/IOP ratio in glaucoma screening.

It has been postulated that the BP/IOP ratio is more predictive of glaucoma than is tonometry alone. An analysis of clinical data from 128 glaucoma patients and 115 normals yields a sensitivity of 80%. Specificity of 86% and relative risk ratio of 22 for this screening test. Evidence of the existence of a dose-response relationship is also found.

Blood Pressure↗
PubMed1975

A nomogram for computing BP/IOP ratios.

Clinical estimates of ocular blood flow, based on a comparison of systemic blood pressure and intraocular pressure, appear to be better predictors of glaucomatous visual field loss than are tonometric estimates alone. One index of ocular hemodynamic status is the blood pressure/intraocular pressure ratio (BP/IOP). A nomogram is presented to aid in calculating this index.

Blood Pressure↗