Hermann von Helmholtz's empirico-transcendentalism reconsidered: construction and constitution in Helmholtz's psychology of the object

This paper aims at contributing to the ongoing efforts to get a firmer grasp of the systematic significance of the entanglement of idealism and empiricism in Helmholtz's work. Contrary to existing analyses, however, the focal point of the present exposition is Helmholtz's attempt to articulate a psychological account of objectification. Helmholtz's motive, as well as his solution to the problem of the object are outlined, and interpreted against the background of his scientific practice on the one hand, and that of empiricist and (transcendental) idealist analyses of experience on the other. The specifically psychological angle taken, not only prompts us to consider figures who have hitherto been treated as having only minor import for Helmholtz interpretation (most importantly J.S. Mill and J.G. Fichte), it furthermore sheds new light on some central tenets of the latter's psychological stance that have hitherto remained underappreciated. For one thing, this analysis reveals an explicit voluntarist tendency in Helmholtz's psychological theory. In conclusion, it is argued that the systematic significance of Helmholtz's empirico-transcendentalism with respect to questions of the mind is best understood as an attempt to found his empirical theory of perception in a second order, normative account of epistemic subjectivity

In vivo measurement of the sagittal depth of the anterior corneal surface

In vivo measurement of the sagittal depth of the anterior corneal surfac

Reliability of biometry.

INTRODUCTION: The refractive power of Pseudophakos is final and the patient must live with any mistake committed (or) be subjected to a very dangerous operation, namely, to the removal and replacement of the intraocular lens (IOL). To ensure that our patient will have the optimal correction, the power of the lens to be implanted must be determined precisely and perfectly in every case. AIM OF THE STUDY: To study the reliability of A–scan biometry in Tertiary Institution where measurements were taken by multiple persons. MATERIALS AND METHODS: A retrospective series of 110 cases of cataract extraction and in the bag fixation of the IOL done in RIO-GOH were investigated. Cataract extraction done by 1) extra capsular cataract extraction 2) small incision cataract surgery and 3) phacoemulsification were included in the study. CONCLUSION: With the evolution of small incision techniques that minimize surgically induced astigmatism, IOL power selection becomes a crucial step for the refractive outcome of cataract surgery. The present study has shown that in Institution where multiple persons perform Biometry chances of postoperative refractive error can be minimized if precise and proper technique is followed and it is possible to have prediction errors below 1.00 D on the average. The chance of postoperative refractive error could be further reduced if SRK T formula is used for IOL power calculation

Ohio State University Bulletin

Classes available for students to enroll in during the 1922-1923 academic year for The Ohio State University

Measuring Corneal Topography Using Wavefront Analysis Technique

Refractive surgery has emphasized the need of accurate and precise methods for measuring the power of the human cornea. Available techniques for measuring corneal topography include keratometry, videokeratoscopy, and scanning slit imaging. A new type of instrument, a corneal topographer based on a Hartmann-Shack wavefront sensor for measuring corneal elevation over a spherical surface, is presented in this thesis. The performed tests of the topography system showed a high accuracy and reproducibility of the measurements on spherical as well as on toric test sample surfaces that approximate the curvature of the central human cornea. A comparison between the data obtained by the topographer and those provided by a videokeratoscope showed that the topographer is as precise as standard instruments used in clinical praxis. The measurements on human corneas demonstrated the importance of a Z-tracker module for the correct placement of the corneal surface. To enhance the accuracy of the topography system, a better tracking of the corneal position is necessary to compensate for the axial eye movements during the examination that strongly affect the measurements. Additionally, more clinical studies are necessary to test the topographer on human cornea and to give an evidence for the clinical acceptance of the instrument

Ohio State University Bulletin

Classes available for students to enroll in during the 1923-1924 academic year for The Ohio State University

Topographic analysis of early changes in corneal astigmatism after manual small incision cataract surgery without suture and with single radial suture using computerized videokeratography

The eyes with single radial anchoring suture tied over sclerocorneal tunnel incision demonstrated mainly with the rule type of astigmatism in early postoperative period, that is steepening in the meridian that intersects the incision. The eyes with sclero-corneal tunnel incision left without suture demonstrated mainly against the rule type of astigmatism in early postoperative period, that is flattening in the meridian that intersects the incision. Both the Groups with sclero-corneal tunnel incision showed a little induced astigmatism with Mean <1 Dioptre. Though mean induced cylinder in sutured eyes was little greater than no stitch group, the differences in amplitude of induced cylinder between two groups were not found to be statistically significant. In case of preexisting significant cylinder, placement of tunnel incision at the steeper meridian causes some amount of decrease in postoperative cylinder by causing flattening in the meridian that intersects the incision only in no stitch group eyes. No cases developed wound leaks or iris prolapse or postoperative endophthalmitis. The eyes left without suture demonstrated physical stability as did those eyes with suture closure. Thus we finally arrived at a conclusion that, properly performed No Stitch Corneoscleral valve incisions give rise to no postoperative complications like would leaks or postoperative iris prolapse and give rise to minimal induced astigmatism, the amplitude of cylinder being indistinguishable from sutured incision. I am following the patients to assess the long term topographic astigmatic changes

Evaluation, prevention and surgical treatment of post-keratoplasty astigmatism with the use of computer assisted videokeratography.

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