Biomedical subjects
Publications and source records attributed to H Littmann.
In a preceding paper with the same title the result was represented by curves which enable factors used in calculating the true diameter to be determined. Instead of the curves a quadratic equation is used to produce the same factors. The data for the equation are given in two tables.
A method is described which allows the real diameter of an object on the fundus to be determined by means of a system of curves which are the result of trigonometrical calculations and which give an approximate value; only a photograph of the fundus, a measurement of the ametropia and of the radius of the anterior surface of the cornea are required. The results can be corrected with a second graph, which makes use of the length of the optical axis of the eye.
As the measurements of the peripheral refraction of the living human eye published till now point out a confusing abundance of variants but no clear results, the peripheral refraction of fictitious model eyes is computed to find out which components influence the refraction and how they do it. Then for some special selected representative eyes the peripheral refraction and the astigmatism are computed and the results analyzed. The result consists in three typical refractioncurves which can be reduced to simple rules. This paper intends to stimulate future experiments on exactly defined conditions.
The new Zeiss Xenon-photocoagulator has considerable advantages. The possibility of converging the light beam allows coagulating even prominent areas (folds) in lensless eyes without difficulty. From our experience Xenon coagulation with individually adapted coagulation offers advantages over argon-laser coagulation with relatively short coagulation times.
Explore the source record for details and available documents.
Based on the anatomical section of an emmetropic eye a spherical or circular fundus is developed by application of a mathematical-statistical method resulting in an optimal approach to the anatomy. The same method is applied to a fundus which is derived by mere computation exclusively from the data of the schematic eye. The results of both methods coincide remarkably well. In this way a schematic fundus is defined as circle with 11.6 mm radius. Its center has a distance of 12.8 mm from the anterior corneal vertex. The applicability of this fundus is discussed.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.