[Influence of body position on ocular cycloposition in patients without binocular vision]. / Lageabhängigkeit der Augenstellung in der torsionalen Ebene bei Patienten ohne Binokularsehen.

PURPOSE: Positionally induced cyclotorsion could be an important factor concerning correction of astigmatism in refractive surgery. Previous studies have shown no influence of body position on cycloposition in healthy subjects with normal binocular vision. METHODS: 10 subjects (median value of age 44.2 years) without binocular vision due to an organic eye disease or to strabismus were examined using three-dimensional video-oculography (3D-VOG). This non-invasive method can record changes in the position of both eyes simultaneously in the x-, y- and z-axes. The cycloposition of the eyes was recorded first in a seated position with both eyes open (test 1), then in a supine position with the right eye closed (test 2), then in a supine position with occlusion of both eyes (test 3), and then in a supine position with both eyes open (test 4). In each of these 4 situations, the eyes were recorded for 1 minute. Cyclovergence was calculated as the difference between the right and the left eye positions. RESULTS: The range of cycloposition of the right and left eye in all 4 tests was very small. 95 % confidence intervals for cycloposition of the right and left eyes and for cyclovergence: cycloposition right eye/cycloposition left eye/cyclovergence: 0.72;0.76/- 0.07;0.01/0.71;0.79 (test 1), 0.23;0.29/0.19;0.33/- 0.81;- 0.63 (test 2), - 0.92;0.7/- 0.51;- 0.37/- 0.79;- 0.45 (test 3), 0.14;0.52/- 0.07;0.31/0.59;0.21 (test 4). There was no statistically significant difference of the cycloposition between the 4 test situations. CONCLUSIONS: The cycloposition of the eyes does not significantly change between seated and supine positions of the body, either in subjects with, or without binocular vision. This means for refractive surgery that a correction of astigmatism, to be performed in the supine position of the patient, can be based on a measurement of the axis of astigmatism obtained in the seated position.

Use of preoperative assessment of positionally induced cyclotorsion: a video-oculographic study.

PURPOSE: Positionally induced cyclotorsion could be an important factor concerning correction of astigmatism in refractive surgery. The method of binocular three dimensional infrared video-oculography (3D-VOG) was used to determine a possible influence of body position on cyclotorsion. METHODS: 38 eyes (19 healthy subjects, median value of age 25.5) with normal binocular vision were examined using 3D-VOG. This method records ocular motions and positions of both eyes simultaneously in the x, y, and z axis. Cycloposition of the eyes was recorded first in a seated position (both eyes open, test 1), then in a supine position (right eye closed, test 2), occlusion of both eyes (test 3), both eyes open (test 4). Cyclovergence was calculated as the difference between the right and the left eye positions. RESULTS: The range of cyclotorsion of the right and left eye in all four tests was between 1.13 degrees excyclotorsion and 0.34 degrees incyclotorsion. There was no statistically significant difference of the median values for torsion for the four test situations. Concerning the influence of body position on cyclotorsion, a statistically significant difference between the different test positions and settings did not exist. Median values for right/left torsion/cyclovergence were: 0.17/0.04/0.02 (test 1), -0.31/-0.71/-0.16 (test 2), -1.09/-0.60/0.82 (test 3), 0.28/0.28/-0.82 (test 4). CONCLUSIONS: Cyclotorsion does not significantly change between seated and supine position in subjects with normal binocular vision and stable fixation. In these subjects, an erroneous refractive surgery due to incorrect measurement of the axis of astigmatism in the seated position and performing the refractive surgery in the supine position, is very unlikely.

Critical perimetry - functioning methods.

Visual field defects without any organic correlate require critical control to avoid inadequate management of psychogenic defects. Which methods are promising to detect psychogenic visual field defects? Twenty ophthalmologically trained volunteers motivated to pretend a concentric visual field loss were tested by manual perimetry with centripetal and centrifugal movement of the stimulus, by evoking saccadic eye movements towards a stimulus outside the subjectively claimed visual field and by observation of the volunteers' strategy searching a stimulus beyond the subjectively claimed borders. Malingering could be proven in 16 persons. The most favourable procedure is to evoke eye movements towards a peripheral stimulus. These movements yield information about the visual field outside the subjectively stated limits.

[An ophthalmologic image databank on the Internet]. / Eine ophthalmologische Bilddatenbank im Internet.

The Internet has become a powerful, international source for information, and it has shown an exponential growth because of the ease of access and the immediate availability of information. We introduced a new ophthalmological atlas including ICD coding on the World Wide Web. So far, more than 500 lantern slides of typical and interesting ophthalmological findings have been selected and digitized. These pictures were integrated in a data base, which was arranged for ease and speed of search and retrieval. In its background, the data base contains a list of over 4700 ICD-encoded diagnoses to which the picture-documented findings are linked. Comments on pictures can be added by the author or by users. The data base contains several lists, such as a list of ICD codes and diagnoses, a list of all pictures with corresponding diagnoses, a list of all diagnoses and number of pictures, a list of those diagnoses for which the corresponding picture is available, as well as a list of comments on each picture. Special program scripts handle the user's search key words for diagnoses and extract the required information out of the data base, using Windows NT. Search results are presented on an automatically built-up webpage. To provide fast speed of search all pictures initially are shown in a small format (thumbnails) with little amount of data. The related full-size picture is retrieved by a single mouse click. Moreover, the name and institution of the author, diagnostical hints and comments on pictures by the author or by users are offered for each diagnosis available. The Giessen Ophthalmological Picture Atlas can be reached under www.med.unigiessen.de in the Internet. It allows a fast search free of charge from all over the world and, therefore, offers an additional option to obtain specific ophthalmological information for various purposes.

[A new site-independent tonometer (ProTon) in comparison with the Goldmann applanation tonometer]. / Ein neues lageunabhängiges Tonometer (ProTon) im Vergleich mit dem Goldmann-Applanationstonometer.

BACKGROUND: A new position-independent and portable Mackay-Marg-tonometer in miniature, the so-called ProTon (PT), was compared with reference to its clinical usefulness with the Goldmann applanation tonometer (GAT), being a commonly accepted reference. METHODS: The intraocular pressure (IOP) in 164 eyes of 85 adults (patients and volunteers without ocular disease) was measured using the sequence GAT, PT and again GAT--each three times in a row-by three different investigators in a randomized scheme. In an attempt to detect any systemic influence, the difference obtained by subtracting the value measured using PT from the value attained using GAT was compared to the central corneal thickness and radius. Moreover, the central IOP readings were compared with the peripheral IOP in 60 eyes of 30 volunteers measured by PT, to detect any possible influence of the locality of measurement. Dependence of measurement on individual influences was examined by comparing PT-values obtained by each investigator. RESULTS: Linear regression analysis between PT (y-axis) and GAT (x-axis) for an IOP range of 0 to 62 mm Hg resulted in the following equation: PT = 1.036 x GAT -2.00 with a PT value standard deviation of 1.65 mm Hg (r = 0.988; p < 0.0001). Reproducibility of each of the three PT-values (mean pair difference of 1.1 mm Hg) corresponded to the analogous first two GAT-values (differences 1.0 up to 1.2 mm Hg). The mean IOP-value of 1) the GAT measurements (1 to 3) was 18.35 mm Hg, 2) of the last three GAT measurements, 17.15 mm Hg and 3) of all PT-measurements, 16.40 mm Hg. No statistical difference was found between the IOP measured centrally and peripherally. A clinically nonsignificant dependency for PT-readings on the examiner was verified. CONCLUSION: Due to the high reproducibility, independency on examiner and acceptable correspondence of PT with GAT values, the PT appears to be a promising new development for use in measuring intraocular pressure. It will be necessary to modify the calibration of PT since IOP measured systematically about 2 mm Hg too low.