Ophthalmic Images of Blur and Blurred Ophthalmic Images: Fuzzy Pictures in Scientific Practice

Abstract

Fuzziness or blur in images deserves critical attention as a subject and resource in scientific research practices and clinical interventions. I discuss how the project of engaging blur in vision optics is embedded in a constellation of different mathematical and pictorial tools, with different standards and purposes, investigative and clinical, often inseparable. An expression of this is the various kinds of pictures of blurred vision, many of which do appear blurred, and their different and shifting roles and uses. Their use runs against the commitment to sharpness as an ideal of, for instance, scientific representation, reasoning and decision-making. Judgments and effective standards of visual precision, or sharpness, are always relative. Different kinds of images include hand drawings, analogical and digital photographs, and computer visualizations. I show how, historically, they have been introduced in an ongoing project of simulation that begins with so-called artificial models, artificial visual aberrations, and photographic simulations and experiments. Computer simulations followed suit, each with their one specific condition. I also show how the different kinds of pictures, like the roles and goals they serve, do not always arise to replace others but instead develop different relations to others and introduce new uses. In the new pictorial regime, research and clinical practice rely on a combination of drawings, different kinds of photographs, and computer visualizations. The simulations and the pictures, I show, play a number of roles: providing illustration and classification, prediction, potential explanations (a deeper level of classification), exploration, testing, evidence for or against explanatory hypotheses, evidence for or against the effectiveness of research tests and techniques, evidence for or against the reliability of diagnostic tests, and the effectiveness of corrective treatments and tracking the evolution of conditions and treatments. My analysis contradicts and supplements a number of other accounts of the significance of images in terms of their content and use. A central issue I focus on, more salient than in the application of mathematics of fuzzy-set theory, is the central interest in the phenomenon of blur in visual experience prompts pervasive and endemic considerations of subjectivity and objectivity. Different relations and tensions between standards of subjectivity and objectivity play a key role in the evolution of research and clinical intervention. This aspect finds expression in the interpretation, production, and use of pictures.