Heinz Rosskothen

Measurement of intraocular lens decentration and tilt in vivo

ABSTRACT A method for measuring the tilt and decentration of intraocular lenses (IOLs) in the static eye using the Purkinje image locations is presented. The patient fixates on a target that is coaxial with the camera or is at a predetermined angle with the camera axis. A telecentric stop is introduced in the camera so the positions of the Purkinje images on the film are independent of their distance from the camera. Measurements of the image locations on the film are used with anterior chamber depth and corneal curvature measurement to calculate the tilt and decentration of the IOL. In a group of 14 randomly selected patients with posterior chamber IOLs, 13 gave Purkinje images that could be measured. The average tilt was 7.8 degrees and the average decentration was 0.7 mm.

Transport of fluid by lens epithelium

We report for the first time that cultured lens epithelial cell layers and rabbit lenses in vitro transport fluid. Layers of the alphaTN4 mouse cell line and bovine cell cultures were grown to confluence on permeable membrane inserts. Fluid movement across cultured layers and excised rabbit lenses was determined by volume clamp (37 degrees C). Cultured layers transported fluid from their basal to their apical sides against a pressure head of 3 cmH2O. Rates were (in microliter. h-1. cm-2) 3.3 +/- 0.3 for alphaTN4 cells (n = 27) and 4.7 +/- 1.0 for bovine layers (n = 6). Quinidine, a blocker of K+ channels, and p-chloromercuribenzenesulfonate and HgCl2, inhibitors of aquaporins, inhibited fluid transport. Rabbit lenses transported fluid from their anterior to their posterior sides against a 2.5-cmH2O pressure head at 10.3 +/- 0.62 microliter. h-1. lens-1 (n = 5) and along the same pressure head at 12.5 +/- 1.1 microliter. h-1. lens-1 (n = 6). We calculate that this flow could wash the lens extracellular space by convection about once every 2 h and therefore might contribute to lens homeostasis and transparency.We report for the first time that cultured lens epithelial cell layers and rabbit lenses in vitro transport fluid. Layers of the αTN4 mouse cell line and bovine cell cultures were grown to confluence on permeable membrane inserts. Fluid movement across cultured layers and excised rabbit lenses was determined by volume clamp (37°C). Cultured layers transported fluid from their basal to their apical sides against a pressure head of 3 cmH2O. Rates were (in μl ⋅ h-1 ⋅ cm-2) 3.3 ± 0.3 for αTN4 cells ( n = 27) and 4.7 ± 1.0 for bovine layers ( n = 6). Quinidine, a blocker of K+ channels, and p-chloromercuribenzenesulfonate and HgCl2, inhibitors of aquaporins, inhibited fluid transport. Rabbit lenses transported fluid from their anterior to their posterior sides against a 2.5-cmH2O pressure head at 10.3 ± 0.62 μl ⋅ h-1 ⋅ lens-1( n = 5) and along the same pressure head at 12.5 ± 1.1 μl ⋅ h-1 ⋅ lens-1( n = 6). We calculate that this flow could wash the lens extracellular space by convection about once every 2 h and therefore might contribute to lens homeostasis and transparency.

Incident light optical sectioning microscope for visualization of cellular structures in the inner ear

An optical sectioning microscope of the scanning slit type has proved useful for visualizing details within the cochleas of guinea pigs. The modifications include specially designed dipping cones to facilitate access to the cochlea

Clinical microscopy of the cornea utilizing optical sectioning and a high-numerical-aperture objective

A doublet contact element was added to a long-working-distance objective to increase the numerical aperture to 0.75 and to maintain the focus during in vivo examination of the eye. Optical sectioning by use of confocal slits permits visualization of weakly scattering structures within the cornea. With photographic film and a 1/60-s exposure time to limit the effect of eye movement, an effective optical section half-thickness of approximately 20 microns was realized. Structures observed in the cornea include epithelial cells (surface, wing, and basal cells), nerve-fiber bundles in the subepithelial region, keratocytes and inflammatory cells in the stroma, and endothelial cells.

Noninvasive optical system for the study of the function of inner ear in living animals

The Hearing Organ has a coiled structure in which the basic geometrical arrangement of the different types of cells is repeated throughout the organ. Hearing organs of different mammalian species also utilize the same arrangement of cells. In order to understand the significance of this arrangement in processing the auditory stimuli it is essential to measure the cellular function in an intact organ of a living animal. The sensory cells in the intact inner ear of a living animal can be visualized in the basal turn of the cochlea through the round window membrane. To achieve this an imaging system is needed to detect the weak reflections from the sensory cells in the inner ear while rejecting strong reflections from structures below and above the region of interest, particularly the round window membrane itself. A confocal microscope/interferometer was developed and built to visualize the sensory cells and to measure their vibration in response to sound applied to the ear. The measuring system and some of its performance characteristics are described.

Confocal slit divided-aperture microscope: applications in ear research.

A confocal, scanning slit microscope that uses separate portions of the objective aperture for illumination and imaging rays achieves a high degree of optical sectioning. This capability permits visualization of individual cells within the intact inner ear in guinea pigs and cats, and it facilitates directing a laser heterodyne interferometer beam so that vibration of selected cells can be measured. A concentric singlet lens is added to the front of a long-working-distance microscope objective to increase the numerical aperture from 0.4 to 0.53 while retaining a working distance of 6 mm. The measured optical-sectioning capability is compared with the theoretical performance and with the calculated curve for a full-aperture pinhole confocal system.