Estimating visual acuity by character counting using the Snellen visual acuity chart.

PURPOSE: This study examines visual acuity estimation with character counting, which can be used in subjects with nonorganic visual loss. METHODS: The right eyes of 35 healthy subjects were fogged with plus lenses and tested with the Snellen visual acuity chart (Reichert 11180). Visual acuity and counting level were assessed under various degrees of fogging, up to a maximal fogged acuity of 20/200. Counting level was defined as the smallest line that subjects could count the number of characters correctly. For each counting level, the visual acuity that 95% of subjects could see equal to or better than was determined. RESULTS: A counting level of 20/10 estimates (ie 95% chance) a visual acuity equal to or better than 20/30. Counting levels 20/15, 20/20, and 20/25 estimate visual acuities of at least 20/50, 20/80, and 20/80, respectively. Counting levels 20/30-20/60 estimate a visual acuity of at least 20/200. CONCLUSIONS: Character counting appears to be a useful technique of obtaining a rough estimate of visual acuity in subjects unable to be tested by standard methods, such as those with non-organic visual loss.

The implementation of a knowledge-based Pathology Hypertext under HyperCard.

A knowledge-based Hypertext of Pathology integrating videodisc-based images and computer-generated graphics with the textual cognitive information of an undergraduate pathology curriculum has been developed. The system described in this paper was implemented under HyperCard during 1988 and 1989. Three earlier versions of the system that were developed on different platforms are contrasted with the present system. Strengths, weaknesses, and future extensions of the system are enumerated. The conceptual basis and organizational principles of the knowledge base are also briefly discussed.

Factors affecting computer-mediated instruction in medical education.

Although computer technology has progressed rapidly in the last decade, the use of computer mediated instruction as an adjunct to medical education has made only limited progress. This paper will attempt to analyze some of the major factors bearing on this limitation will review those areas where computer based instruction is potentially of greatest use, and will suggest means by which medical education can make greater use of the rapidly evolving information technologies. The Medical PLATO project at the University of Illinois will be used as an example to illustrate many of the points relating to the development of this field.

Computers and videodiscs in pathology education: ECLIPS as an example of one approach.

We have enumerated ways in which the evolving computer and videodisc technologies are being used in pathology education and discussed in some detail the particular use with which we are most familiar, text management. While it is probably premature to speculate as to how these technologies will ultimately affect pathology education, one recent trend--the convergence that seems to be developing between those working on expert consulting systems and those working primarily on educational applications--will probably influence this impact substantially. We believe that we are moving, from opposite directions, toward the same end result, namely, the use of machine intelligence to facilitate and augment human learning. We expect that, as the two groups come closer together, very powerful, interesting, and eminently useful educational tools will emerge. While this is occurring, we think that most would agree that one of the very urgent needs is to develop forums in which the academic and practice communities can interact with researchers and developers. With apologies to Clemenceau, computers are rapidly becoming too important to be left exclusively to computer scientists. Such forums would serve to give these communities a chance to learn what the new technologies have to offer and give developers a better idea of where these technologies can make the greatest contributions.