Diurnal fluctuation of higher order ocular aberrations: correlation with intraocular pressure and corneal thickness.

Purpose: Optimal wavefront-guided refractive corneal laser surgery requires sufficiently exact data of optical higher order aberrations. We investigated whether these aberrations had a systematic during-the-day variation, studied the range of variation, and changes in intraocular pressure and central corneal thickness.

Methods: In 22 eyes of 22 young volunteers the optical aberrations of higher order were measured by means of a Tscherning-type ocular aberrometer three times during one day (7 AM, 12 noon, 4 PM).

Ocular optical aberrometer for clinical use.

Higher-order optical errors of the human eye are often responsible for reduced visual acuity in spite of an optimal spherical or cylindrical refraction. These optical aberrations are of natural origin or can result from operations in the eye that involve optical structures. The ocular aberrometer presented is based on Tscherning's aberroscope.

Clinical experience with the Tscherning aberrometer.

Purpose: With the aberrometer based on Tscherning's principle, measurements of wavefront aberrations of human eyes with high accuracy and reproducibility are available for standard diagnostic investigations.

Methods: During investigational and clinical trials, wavefront-aberrations of about 300 human eyes were measured and evaluated within the last few years.

Results: measurements are presented in terms of Zernike coefficients and as height maps that can be converted directly to ablation profiles for wavefront-guided laser treatments.

Principles of Tscherning aberrometry.

Higher-order optical errors of the human eye are often responsible for reduced visual acuity in spite of an optimal spherical or cylindrical refraction. These optical aberrations are of natural origin or can result from operations on the eye involving optical structures. The presented wavefront analyzer is based on Tscherning's aberroscope.

A new perfusion cell chamber system for determination of heat shock effects by means of video-enhanced microscopy.

A user friendly microscope perfusion chamber which allows real-time observation of individual cells at high magnification has been designed. An integrated multisensor was used to monitor the cell culture conditions. To prove the potential of the system heat shock experiments were performed.

Ocular optical aberrations after photorefractive keratectomy for myopia and myopic astigmatism.

Objectives: To study the effects of photorefractive keratectomy on ocular optical aberrations and to establish correlations with glare vision and low-contrast vision.

Methods: Preoperative ocular aberroscopy of 15 eyes undergoing photorefractive keratectomy was compared with aberroscopy at 3 months postoperatively by means of a newly developed automated aberroscope of the Tscherning type. The correlation of the wavefront errors with best spectacle-corrected visual acuity, low-contrast visual acuity, and visual acuity under glare conditions was analyzed.

Effects of photorefractive keratectomy and cataract surgery on ocular optical errors of higher order.

Background: This pilot study was carried out to assess the effects of photorefractive keratectomy (PRK) for myopia and myopic astigmatism and cataract surgery on the ocular optical aberrations of higher degrees.

Methods: The optical aberrations were measured in 12 patients before and after PRK and in 10 patients after cataract surgery with a video aberroscope for clinical use (based on Tscherning's aberroscope) designed by the authors. To characterize the optical performance of the eye the deviation of the wavefront of a foveal image point from its ideal (spherical) shape (wavefront aberration) was determined.

Effects of heat shock on the functional morphology of cell organelles observed by video-enhanced microscopy.

In living astrocytes and MDCK cells we observed morphological phenomena during and after heat shock (HS) utilizing our new perfusable microchamber system, which monitors pH, pO(2), pCO(2), and temperature. By means of electronic light microscopy and confocal laser scanning microscopy, mitochondria were demonstrated to swell and to reduce their motility. The specific fluorescent probe MitoTracker Green revealed that the mitochondrial morphology changed from a rodlike into an annular shape with a central vacuole-findings which were corroborated by transmission electron microscopy.

[Measuring device for determining monochromatic aberration of the human eye].

Background: After refractive or cataract surgery, ocular optical errors can occur that are not correctable with spherical or astigmatic lenses and are probably responsible for the fact that in many cases the best possible (retinal) acuity is not achieved in spite of an optimum refraction. Assessment of these aberrations in the clinical routine is an important first step towards documentation and correction of these errors with modern photorefractive methods. PRINCIPLE OF MEASURING: Ocular optical errors are assessed from the viewpoint of the wave property of light as an aberration of the real wavefront of a central retinal image point from the ideal spherical from (wavefront aberration).

Real time recognition of complete atrioventricular blocks.

Common heart arrhythmia monitors are limited to the electrical activity of the ventricles. Severe cardiac malfunctions exhibit typical defects of atrioventricular conduction which often can be efficiently treated with medicine or electrotherapy. The method described here enables the detection of complete atrioventricular blocks and may be used for the improvement of arrhythmia monitoring.